I am done with screwdriver starts!!! Is one or the other better,a bosch relay or a ford solenoid? Looks like a bosch relay is cleaner with the battery cable not needing to go to the relay? I just want to be done with this issue. Thanks.

http://novaresource.org/images/solenoid04.gif

Hook it up like this.

Is there a part number,or do I just ask the kid at the counter for a 30A bosch relay.

Just ask for a Bosch relay. It's a standard item at any auto parts store, car stereo place, Radio Shack, etc. You might not get an actual Bosch™ relay, but the generic ones will work, too.

You can always install a permanent magnet starter and not have to deal with the additional wiring...

I don't see how a bosch relay will help a hot start or heat soak problem. The trouble is with the starter solenoid itself. Putting a bosch relay in series does nothing to alleviate the problem. A bosh relay only handles 30 or 40A.

The Ford solenoid is build to handle the full load of the starter. When you install the ford solenoid, you essentially short out the build in solenoid contactor with the ford solenoid's contactor.

Dennis,I really like the sound of no extra wiring...has your starter been problem free?

So far so good, I have put many starts on it but only had one occasion where the conditions were right for the no starts I was geting since installing it. It worked then so I'm happy so far...

I don't see how a bosch relay will help a hot start or heat soak problem. The trouble is with the starter solenoid itself. Putting a bosch relay in series does nothing to alleviate the problem. A bosh relay only handles 30 or 40A.

The Ford solenoid is build to handle the full load of the starter. When you install the ford solenoid, you essentially short out the build in solenoid contactor with the ford solenoid's contactor.

The starter solenoid itself only requires about 8 amps to fully engage. A 30 amp relay is quite capable of handling this current.
The 'heat soak' problem stems from the deterioration of the original wiring to the starter solenoid, and the fact that the copper solenoid coil has a positive temperature coefficient of about +0.393 percent per degree C.
A Ford 'solenoid' isn't really a solenoid, it's just a heavy duty relay. The solenoid is the magnetic mechanism that pulls the starter gear into the flywheel.

The starter solenoid itself only requires about 8 amps to fully engage. A 30 amp relay is quite capable of handling this current.
The 'heat soak' problem stems from the deterioration of the original wiring to the starter solenoid, and the fact that the copper solenoid coil has a positive temperature coefficient of about +0.393 percent per degree C.
A Ford 'solenoid' isn't really a solenoid, it's just a heavy duty relay. The solenoid is the magnetic mechanism that pulls the starter gear into the flywheel.

I don't dispute the points you've made here, but I'm still not convinced that a relay will help with a heat soak problem. The ignition switch can handle the 8amps just as well as a bosch relay can. The heat soak issue is caused by a couple of things. First the solenoid windings build up enough resistance that it won't engage and second, the contactor in the soiloid won't provide a good enough connection to handle the starter current. The ford solenoid (a.k.a contactor a.k.a relay) will partially address the first issue and fully addresses the second issue. The bosch relay won't address either.

I don't dispute the points you've made here, but I'm still not convinced that a relay will help with a heat soak problem. The ignition switch can handle the 8amps just as well as a bosch relay can. The heat soak issue is caused by a couple of things. First the solenoid windings build up enough resistance that it won't engage and second, the contactor in the soiloid won't provide a good enough connection to handle the starter current. The ford solenoid (a.k.a contactor a.k.a relay) will partially address the first issue and fully addresses the second issue. The bosch relay won't address either.

Could you put your theory into electrical terms? What does the Ford relay accomplish that the Bosch relay doesn't? What do you suppose the difference in contact resistance is at 8 amps?

It's not only the ignition switch in the circuit, there are several connections and a neutral safety switch. Each connection will deteriorate over time as they are not gas tight. They corrode and get loose..
Since you are switching an inductive load, each time you break the ignition switch you get an arc. After several years of arcing, the resistance of the ignition switch contacts increases. How much would you calculate that it needs to rise to significantly affect the circuit?
Let's say your solenoid coil has a resistance of 1.3Ω and the rest of the circuit is about 0.3Ω. How much would the circuit resistance have to increase to drop the current to 6 amps @ 12v.? If the solenoid temperature goes up from 25°C to 100°C how much does the coil resistance change?

You can always install a permanent magnet starter and not have to deal with the additional wiring...

Ditto on that. I had the same issue, no hot start. I know my wiring is old but it is in great shape and all the terminations have been cleaned since I bought it, it was a heat issue I'm sure. I did not want a bunch of wiring that didn't belong in there either, plus I have 11.5:1 compression and a locked out distributor, so I was taxing my starter to begin with.
I went with a powermaster "ultra torque" series, it's small, starts every single time effortlessly, plus it only weighs 8.5 pounds. I highly reccomend one :thumbsup:

I don't see how anybody has problems with heat soak. I have never had a problem with my car not starting when it gets hot. It has headers and it starts everytime even on 100* days. I have never had to replace my alternator because the solenoid gave out and I don't have a heat shield on the starter either. I have had the car for around 8-9 years now and I drive it damn near everyday, Hot or cold, and it has never left me stranded due to solenoid failier.

The Ford relay is not a relay, it is a solenoid. Relays and solenoids are designed to handle different load amounts.

The Ford relay is not a relay, it is a solenoid. Relays and solenoids are designed to handle different load amounts.

A solenoid is a coil of insulated or enameled wire wound on a rod-shaped form made of solid iron, solid steel, or powdered iron. Devices of this kind can be used as electromagnets, as inductors in electronic circuits, and as miniature wireless receiving antennas.

In a solenoid, the core material is ferromagnetic, meaning that it concentrates magnetic lines of flux. This increases the inductance of the coil far beyond the inductance obtainable with an air-core coil of the same dimensions and the same number of turns. When current flows in the coil, most of the resulting magnetic flux exists within the core material. Some flux appears outside the coil near the ends of the core; a small amount of flux also appears outside the coil and off to the side.

A relay is an electrical switch that allows a low power to control a higher one. A small current energizes the relay, which closes a gate, allowing a large current to flow through.

The large coil of wire on the side of your starter that pulls in a ferrous rod to engage the starter gear is a solenoid.

The Ford part used to switch a large amount of current through a set of contacts by using a small amount of current in the coil is a relay. It is functionally the same a Bosch relay, just capable of handling more current.

I don't see how running the purple 'S' wire through a relay can help. Isn't the solenoid like a relay in the fact it is on or off?

Basics: How are your battery cables? What size are they? How are your grounds? How is the battery (and your charging system)? How is the starter?

This is confusing...my old 69 never had a hot start problem...but this 68 sure does.The battery and alternator are new,the cables are new,the grounds have star washers...it just heat soaks.I have put two new solenoids on it and still the same thing.I have not changed the starter because when this occurs there is nothing no click nothing,when I let it cool for a 1/2 hour it starts right up.Think I am going to order the starter Dennis used for 75.00 its cheap.Thanks all.

I don't see how running the purple 'S' wire through a relay can help. Isn't the solenoid like a relay in the fact it is on or off?

Basics: How are your battery cables? What size are they? How are your grounds? How is the battery (and your charging system)? How is the starter?

The problem stems from the external circuit resistance compared to the resistance of the solenoid coil. The coil is a low impedance device that requires about 8 amps to get it to work reliably. The current for the solenoid coil is provided by a circuit that goes from the battery to the ignition switch, the neutral safety switch, and to the starter. Over time, the contacts are degraded and the connections deteriorate. The Bosch relay requires a lot less current to activate it, so the external wiring has very little effect as it only has to provide about 60 milliamps.

Wiring in a relay with short wires and no switches will provide the solenoid coil with a much more reliable supply of current. There is a post running now about putting relays in the headlight circuit, and folks seem to understand this concept. A headlight relay is exactly the same effect as putting a relay in the solenoid coil circuit. More current for better operation.

The solenoid functions as a relay as it has a set of high current contacts that engage when the solenoid pulls in. These high current contacts control the current to the starter motor.

Could you put your theory into electrical terms? What does the Ford relay accomplish that the Bosch relay doesn't? What do you suppose the difference in contact resistance is at 8 amps?


Don't forget that when you install a ford relay, you short out the starter solenoid's contactor. So the ford relay handles the full starter amperage (more than 100Amps) while the bosch relay setup is only handling the starter solenoid current (8amps). The ford relay and bosch relay setups are not the same. And as I've said before, the bosch relay won't buy you much.

Don't forget that when you install a ford relay, you short out the starter solenoid's contactor. So the ford relay handles the full starter amperage (more than 100Amps) while the bosch relay setup is only handling the starter solenoid current (8amps). The ford relay and bosch relay setups are not the same. And as I've said before, the bosch relay won't buy you much.

A relay is a relay, you can and should use the Ford relay exactly like the Bosch relay. No need to introduce other problems into the circuitry by shorting the solenoid to the battery cable.

IMHO go with the ford remote solonoid. I used one for years on a 12.8 to 1 motor with 1 7/8 headers that hugged the starter. So with that said I am wondering if you have checked the basics? Is you timing too far advanced? This would cause you load to go through the roof. I am confuded about the extra wiring. Its really just one extra cable and a jumper in the starter.

A relay is a relay, you can and should use the Ford relay exactly like the Bosch relay. No need to introduce other problems into the circuitry by shorting the solenoid to the battery cable.

Sorry onovakind. You got some bad info there. Perhaps you're getting annoyed with this thread as I am, but your statement is incorrect.

Edit: I decided I should support my argument with examples. I found there are lots of inaccurate posts out there that don't show the shunt that bypasses the solenoid contactor. Here is a "correct" version:
http://www.1badriv.com/Ford-Solenoid.jpg

At first I had quoted the chevelles.com site as a correct version, but upon looking closer, it is incorrect.
http://www.chevelles.com/techref/tecref4.html

Also, I know there are lots of MadElectrical fans out there. If you look at there advertisement they give you just a peak at the schematic. It doesn't clearly show the shunt. But if you look in the upper right corner of the picture, you'll see a metal strap that is the shunting bar.
http://www.madelectrical.com/catalog/st-1.shtml

That's the trouble with getting an electrical engineer involved in an electrical thread. He tends to know how electrical things work, and has a propensity to call a relay a relay. He probably also knows how a Ford starter works, and what the Ford relay actually does in the Ford, and why there's no solenoid used on a Ford.

There's a problem with connecting the solenoid coil to the battery terminal, the 'shunt' as you call it. If the starter motor retains some magnetism or is a permanent magnet starter, it will act as a generator and cause the starter motor to remain engaged for a time after you release the key. This problem is described pretty well by Powermaster in their FAQ section.
http://www.powermastermotorsports.com/faq-starter.html

There is no reason to run the entire starting current through more than one set of contacts unless it is dictated by the rules you are racing under. Here's another schematic that uses the Ford relay to provide the solenoid with full battery voltage. This is the way I do it.

http://home.comcast.net/~onovakind67/starterrelay.GIF

...There's a problem with connecting the solenoid coil to the battery terminal, the 'shunt' as you call it. If the starter motor retains some magnetism or is a permanent magnet starter, it will act as a generator and cause the starter motor to remain engaged for a time after you release the key. This problem is described pretty well by Powermaster in their FAQ section.
http://www.powermastermotorsports.com/faq-starter.html

...Here's another schematic that uses the Ford relay to provide the solenoid with full battery voltage. This is the way I do it.



Good point about the starter acting as a generator. I could see that happening.

In the schematic you've posted however, thats no different than the relay that started this thread. You've got a 200A contactor relay handling an 8A load. I'm sure it works quite dandy, and may even look cool, but it's overkill. Unless the ford contactor carries the starter current, it ain't buyin you much. It certainly won't cure any heat-soak problems though it may mask an ignition switch issue or other wiring problems that impead current flow on the start wire.

the ford solenoid uses a ferrous rod to force a conductive bar across 2 contacts inside the body of the unit, therefore it is actually a solenoid...it is however much more compact, and requires less amperage to engage...the heatsoak issue is due to increased resistance in the coil of the chev solenoid...basically, it can pull the bendix into the flexplate/flywheel, but cant pull hard enough to make a good contact between the batt and starter contacts...therefore you here a click and maybe a slow turn, but no start...the addition of the ford solenoid utilizes the chev solenoid to pull the bendix into the flexplate, and the ford solenoid to carry current to the starter motor...i`ve never seen a bosch relay setup work, and cant see how it would being it cant carry the 130 or more amps req`d to spin the satrter over, but i`ve been wrong before...if i am, educate me...(no digs meant)

Ok, since this thread is still going here is my hot start experience. I have a 68 327/210 hp base engine with factory manifolds and I use to experience the hot start problem. I added a shield, then replace starters, solenoid, ignition switch, etc and still if I had to turn it off when it was hot I usually heard the click, click, click. At least twice I was towed home and as soon as it was unhooked from the wrecker it would start. I then remembered an old hot rod magazine article I read back in the 70's so I installed the Ford Solenoid (mounted on the inner wheelwell) as per the previous thread and I have never ever had the hot start problem again. I think moving the wiring and the solenoid away from the exhaust manifold heat is what did the trick. So my vote would be for the Ford Solenoid. But I have to tell you it killed me having a Ford part on my Camaro so during my current restoration I am going back to the old set up and hopefully I will have fixed the problem with new exhaust manifolds and repaired wiring.

Mike

Good point about the starter acting as a generator. I could see that happening.

In the schematic you've posted however, thats no different than the relay that started this thread. You've got a 200A contactor relay handling an 8A load. I'm sure it works quite dandy, and may even look cool, but it's overkill. Unless the ford contactor carries the starter current, it ain't buyin you much. It certainly won't cure any heat-soak problems though it may mask an ignition switch issue or other wiring problems that impead current flow on the start wire.

You're exactly right, the two circuits are electrically the same. When I can go to the boneyard and come out with a 200A relay for $1.50 with everything I need on it, I'll take it. You may know that some older cars need an auxiliary contact on the starter to bypass the ignition ballast resistor. Most Ford relays have this provision included in the $1.50, while you'd have to have a DPST Bosch to get the same isolation.

A 200A relay will handle the 8 amps with no problem, the contact resistance is even lower than the Bosch relay. If you understand contact resistance, you know that less is better. What it really buys me is a direct line to the battery that will provide the most voltage to the starter solenoid.

High impedance circuits 'mask' all kinds of problems. Reducing the circuit current to less than 10% of the design current has a real soothing effect on the circuitry and the mask will probably outlast the car.

How about this quote from the Mad Electrical site:

This is the type of problem, which will be cured with installation of the START'M UP kit. The problem occurs because the large solenoid on the GM starter draws 40 to 50 amps at the moment the key is turned to "START." And that large amount of current must flow through a very lengthy circuit, from the battery to the dash area. Through dash wiring and switches, back out through the under-hood wiring, finally to the starter.
http://www.madelectrical.com/catalog/st-1.shtml

Where in any electrical book would you learn that the initial current in an almost purely inductive circuit would be more than the steady-state current? Ol' Joe Henry would be rolling over in his grave...

the ford solenoid uses a ferrous rod to force a conductive bar across 2 contacts inside the body of the unit, therefore it is actually a solenoid...it is however much more compact, and requires less amperage to engage...

In the same sentence you could call the GM solenoid a relay because it uses a small amount of current to control a large amount of current through a set of contacts.


...the addition of the ford solenoid utilizes the chev solenoid to pull the bendix into the flexplate, and the ford solenoid to carry current to the starter motor...

The GM solenoid acts just like it always does, it carries all the starter motor current through its contacts. Depending on how you wire it, the Ford relay can carry all the GM solenoid current and all the starter current, or just the GM solenoid current. I don't know any electrical designers who would run the entire starting motor current through two sets of contacts.

i`ve never seen a bosch relay setup work, and cant see how it would being it cant carry the 130 or more amps req`d to spin the satrter over, but i`ve been wrong before...if i am, educate me...(no digs meant)

The Bosch relay doesn't carry 130 amps, just the roughly 8 amps of GM solenoid coil current. It is only used to actuate the solenoid, the starter motor current goes the regular route through the high current contacts at the bottom of the solenoid.

I say you bypass the 3 items it could be 1 at atime and replace the worn part when found.
Can you bypass the ignition switch contacts? Jumper wire?
Bypass the neutral safety switch (safely) Make sure its in park!
I have seen wires corroded at the firewall junction block before. Pull the block and inspect.
You say the screwdriver method works. This tells me it would have to be somewhere from the ignition switch to the starter. You bypassed all these items with a screwdriver.
I have seen hot start problems due to other things as well.
Ignition timing, to small of a +battery cable. I now use welding cable.
Good luck!

when hooking up a ford solenoid to cure the hot start problem, i relieve the chevy solenoid from its duty of making connection to the starter motor...a wire is connected between the starter motor lug on the chev solenoid and the starter motor lug of the ford solenoid...this eleviates the 2 sets of contact issue, as there could be potential for twice the potential for a set of contacts to fail...i referenced your post to state that the ford solenoid is actually a solenoid as per your own description...i realize that the bosch relay is only carrying enough load to engage the chev solenoid...my point is that at a point of heat soak, i dont believe there can be enough current put to the chev solenoid to make a strong connection in addition to overcoming the bendix and spring...whatever...if you use a ministarter, you wont get this problem anyway, and they`re 130.00 in jegs...problem solved...lol...

Bypassing the GM solenoid high current contacts can be detrimental to your flywheel. The reason for the high current contacts at the end of the GM solenoid travel is to allow for the Dyer drive to engage the flywheel before the motor starts rotating. You don't want the motor running before you engage the gear. Pulling the solenoid to the point of contact takes very little more current than simply engaging the gear.
If the resistance of a typical GM solenoid is 1.3 ohms @ 70°F, what is the resistance of the solenoid at 250°F?

i cant calculate that with the information given. how do you know what the resistance will be if there are more windings with a smaller guage wite, or less windings with a larger guage wire and so forth???not sure, but a 22 guage wire will carry less load at 250 deg than a 14 guage wire, right???and the starter motor is fluted at the bendix gear end to help facilitate gear engagement...if you bench test a starter and hook up to the starter motor lug directly, the torque of the motor will "throw" the bendix out, if only for a second...it returns in due to the spring in the solenoid, but if applying power to both at the same time, the motor doesnt have to overcome the spring tension...in fact, this is how all the sbc/bbc ministarters i`ve used work...they even state in the instructions that the bendix will stay engaged in the flywheel until the motor starts and spins fast enough to "throw" the bendix back out of the starter...all this back and forth junk isnt helping sc42 with his question...its only clouding the answer, so i think you should get a mini, or use a ford SOLENOID...dennis says he has good luck with the perm mag motors, and thats prolly good advice also...onovakind says just adding a relay to the momentary side of the solenoid is all ya need...i`ve never used this meathod, but he`s a smart guy, so this may very well be all ya need...

You can calculate the increase in resistance very easily. It makes no difference what the wire size is or how many coils there are, all you need to know is the temperature coefficient of copper - it's 0.393%/°C. 70°F to 250°F is a change of 180°F or 100°C. 100 x 0.00393 x 1.3 = .51 ohms increase for a total of 1.81 ohms @ 250°F. If you apply the same 12v in each situation, you will have 9.23 amps to the cold coil and 6.63 amps to the hot coil, a 29% reduction in current.

So there you have it. Install a B&S recoil starter on the h/bal with compression release and problem is solved!

I've instaled both alternatives on several ocations, with the best results obtained from the ford starter relay by-passing the starter's internal contacts. I make the jumper from the "S" terminal to the starter terminal with a piece of 1/2 copper pipe. In my experience, the Bosch relay tends to reduce the annoying "click" like in 60% of the times. If you don't like the tipical ford relay design, you can ask for a later model ford starter relay. My brother bought one I instaled in his wife's 93 Toyota Corolla, which always failed in the least opportune situations by the way. Something ± like this one.
http://www.raskcycle.com/harley/electric/40110.jpg

I had no idea I was gonna start this....I ordered the Quality Power starter that Dennis recommended.Thanks everybody for all the help.With all that I learned now I just wonder what I lost. Lol

unfortunately, you asked for the time, and found out how to build a clock...lmao...

I am done with screwdriver starts!!! Is one or the other better,a bosch relay or a ford solenoid? Looks like a bosch relay is cleaner with the battery cable not needing to go to the relay? I just want to be done with this issue. Thanks.

I am done with screwdriver starts!!! Is one or the other better,a bosch relay or a ford solenoid? Looks like a bosch relay is cleaner with the battery cable not needing to go to the relay? I just want to be done with this issue. Thanks.

It depends on what you're trying to accomplish onavakind. If it's hot starts you're dealing with, I don't think the bosch relay will solve your problem. A ford solenoid will IF you shunt the motor feed to the solenoid B+ terminal. But as you've read, there are risks to that approach as well.

So perhaps the bosch vs ford relay discussion has come full circle - don't do either one. Get a better starter. That would be by far the cleanest and most fool-proof way to go. Personally, I use an aluminum heat sheild around mine and it works just fine.

It depends on what you're trying to accomplish onavakind. If it's hot starts you're dealing with, I don't think the bosch relay will solve your problem. A ford solenoid will IF you shunt the motor feed to the solenoid B+ terminal. But as you've read, there are risks to that approach as well.

So perhaps the bosch vs ford relay discussion has come full circle - don't do either one. Get a better starter. That would be by far the cleanest and most fool-proof way to go. Personally, I use an aluminum heat sheild around mine and it works just fine.

I'll agree that a good permanent magnet gear reduction starter would be the best way to go. I don't agree with the voodoo electrical theory based on old wives tales. Perhaps you can show some sound circuit analysis showing exactly why a Bosch relay isn't capable of passing sufficient current to operate the solenoid on the starter.
Assume the following:
The battery voltage is a constant 12v under all conditions at the battery terminals.
The battery cable is 1 gauge cable 5' long from the battery to the starter, including any intervening connections.
Connections are perfect.
The Ford contacts have 0.002 ohms of resistance each, and there are 2 contacts in the unit.
The Bosch relay has 0.02 ohms of contact resistance for the single contact.
The starter draws 125 amps
The solenoid draws 8 amps
The solenoid wiring is 12 gauge wire 5' long except where it is jumped.

Which method of wiring will provide the most voltage to the solenoid?

1. A Bosch relay as shown in the second post?
2. A Ford relay as shown in this link http://www.1badriv.com/Ford-Solenoid.jpg
3. A Ford relay connected as per the 23rd post?

hrmmm... so the real heat soak problem is the lack of current due to increased resistance in the coil of the solenoid? Is a EE still around this thread? How hard would it be to make a current-limiting circuit to drive the S terminal of the solenoid, such that this circuit will bump the voltage up to achieve the desired current to actuate the solenoid? Or somehow dump the charge from a capacitor to give the solenoid a swift kick when you apply power?

How hard would it be to make a current-limiting circuit to drive the S terminal of the solenoid, such that this circuit will bump the voltage up to achieve the desired current to actuate the solenoid? Or somehow dump the charge from a capacitor to give the solenoid a swift kick when you apply power?Ain't gonna happen, if you need more power out, you're still gonna need even more power in than out.

A capacitor does store energy, but its discharge time, 90% fall time, is measured in milliseconds, depending upon the resistance within the circuit. The only capacitor delivering power for the amount of time needed is the battery.

hrmmm... so the real heat soak problem is the lack of current due to increased resistance in the coil of the solenoid? Is a EE still around this thread? How hard would it be to make a current-limiting circuit to drive the S terminal of the solenoid, such that this circuit will bump the voltage up to achieve the desired current to actuate the solenoid? Or somehow dump the charge from a capacitor to give the solenoid a swift kick when you apply power?

The increased resistance of the solenoid coil is just one element of the problem. The degradation of the external wiring is another. You have many chances for bad connections in the circuit that includes several connectors, the neutral safety switch and the ignition switch. Another contributor is the inductive kick of the coil, when you release the ignition switch the collapsing magnetic field will cause an arc across your ignition switch, resulting in pitted contacts and higher contact resistance. Over the years it adds up.
Because the solenoid coil has a relatively low resistance, the effect of a small change in resistance in the external circuit will have a great effect on the operation. Another thing that usually happens during the later years of these cars lives is the addition of a tubular exhaust system that presents more heat directly to the solenoid, so you are losing on both ends, more heat and more series resistance.
Adding an auxiliary relay to switch the solenoid current has two immediate effects. First, it increases the impedance of the load on the ignition circuit as the coil of the auxiliary relay will have an impedance much higher than the solenoid, resulting in a greatly reduced current in the ignition circuit and a lesser consequence of faulty connections. In addition, it will provide the maximum possible current to the solenoid for its operation by eliminating the large external circuit in series with the solenoid.
A voltage doubler. as previously noted, would be a costly solution. Easier solutions would be to use a heat shield, an auxiliary relay and a more modern starter.

Deleted a misdirected rant.

dave, i did that this morning...lmmfao...

I had no idea I was gonna start this....I ordered the Quality Power starter that Dennis recommended.Thanks everybody for all the help.With all that I learned now I just wonder what I lost. Lol

I solved my heat soaked solenoid problems very simply. I believe my problem had nothing to do with E over I*R (not voltage or current related), but was related to a mechanical bind between the plunger and the cylinder it slides in. As the temperature of the solenoid is heated due to exhaust manifold heat transfer, the plunger would bind. I simply installed a hi temp solenoid sold at various outlets. I used MCCP at 815-648-1700 Ron Normann will set you up. Quick simple and inexpensive.

It solve that problem on three cars I have owned...
Good luck

That's some interesting physics. You've got a ferrous slug in a ferrous cylinder with about 0.015" of clearance at room temperature. If I heat the cylinder up, does the bore size increase or decrease?

If the slug is 1" in diameter at 75°F, how hot would you have to get it to expand 0.015" if the COE of the slug is 6 micro-inches per inch per degree F?

and to think I never looked at this thread because I just thought (from the title) that it was someone telling us how he solved his heat soak problem.

I shore did miss some fun times.

onovakind, if you post in this thread again, you will get a vacation.

That's some interesting physics. You've got a ferrous slug in a ferrous cylinder with about 0.015" of clearance at room temperature. If I heat the cylinder up, does the bore size increase or decrease?

If the slug is 1" in diameter at 75°F, how hot would you have to get it to expand 0.015" if the COE of the slug is 6 micro-inches per inch per degree F?

You can try to make it as complicated as you want. I am not trying to impress anyone, you believe its current drop due to an increase in temperature/resistance and I don't based on my experience using hi temp solenoid. It is my understanding that on hitemp solenoids they opened the bore tolerance. Possibly in may have something to do with the coil/field they use. No I did not check to see if the coil resistance or number of windings was different between a standard and a hi temp.

I only replaced the solenoid and amazing all my voltage drops (your theory) disappeared.

I also understand the physics behind larger diameters expanding more than smaller diameter so yes if they are made of the same it should never bind regardless of heat applied. However are you sure these ferrous materials have the same expansion coefficient.

Finally, I was simply suggesting something simple that has had practical success when I experienced a similar problem.

You don't have to have the same coefficient of expansion. If I put a 4" diameter aluminum piston in a 4.005" bore cast iron cylinder at 70°F, how hot could they get before they seized up? The COE of iron is 6 x 10-6 in/in/°F and the COE of aluminum is 12 x 10-6 in/in/°F. Could I still slide the aluminum piston up and down in the cylinder if the cylinder and piston temperature was 270°F? At what point would they seize?
The increase in the coil resistance when the coil is heated isn't a theory, it's physics. Copper has a positive temperature coefficient and when you heat it, the resistance goes up.
I hope all your voltage drops didn't disappear. You can't operate without them. If E = zero, there is no I. P = IE and if there is no E there is no P.

so those who cant do teach???college educated people are better at fixing these problems than highschool educated people???physics books are a great tool, and have a place in the industry, but these are real world parts that dont have the exacting tolerances all the time that your book is speaking of...in addition, trying to make everyone feel stupid by throwing string theory out there will only alienate the person doing the "teaching"...i`ve already discounted some of the stuff you said with your own examples!!!you are obviously a very educated guy, but the reason i kee[p coming back to this thread is because you done seem to be much smarter than alot of us on real world stuff, and you like to present yourself as god,super tech of camaroverse...sorry for the rant, and no offence ment onovakind, but chill out a little!!!

You don't have to have the same coefficient of expansion. If I put a 4" diameter aluminum piston in a 4.005" bore cast iron cylinder at 70°F, how hot could they get before they seized up? The COE of iron is 6 x 10-6 in/in/°F and the COE of aluminum is 12 x 10-6 in/in/°F. Could I still slide the aluminum piston up and down in the cylinder if the cylinder and piston temperature was 270°F? At what point would they seize?
The increase in the coil resistance when the coil is heated isn't a theory, it's physics. Copper has a positive temperature coefficient and when you heat it, the resistance goes up.
I hope all your voltage drops didn't disappear. You can't operate without them. If E = zero, there is no I. P = IE and if there is no E there is no P.

OK, let me make it clear... The root cause of my problem was solved with a hi temp solenoid. Every car solenoid has a reduction in power( E x I) when heated, yet 99.999 don't have problems. I bet those design engineers kinda took the heat factor and losses into consideration. Now my suggestion is simple, reinventing the wheel as you previously sugested with different motors, relays and such is NOT required. If you want a simple low cost solution that works (NOT JUST IN THEORY) give the solenoid made specifically for this hitemp (application) a try. The theory I was questioning was YOUR theory on why the solenoid would not activate. Hands on practical solutions are what work for me, I'll leave reinventing the wheel to other such as yourself.

Wow, what a debate! It looks like there are five types of people reading this post:
1-Those who want to know if the Bosch relay is good enough or if the Ford relay (“solenoid”) is needed. (Or if the heavy duty solenoid alone will help.)
2-Those who are convinced the Ford part is required. (And just don’t want group 1 wasting their time on other options that won’t work.)
3-Those who are convinced the Bosch relay will solve the problem. (And just don’t want group 1 wasting their time on options that are overkill or don’t work.)
4-Those who believe that the heavy duty solenoid is all that is needed. (And just don’t want group 1 wasting their time on options that are overkill.)
5-Those who are just enjoying (or frustrated by) watching groups 2 and 3 argue their points, knowing each opposing group isn't really listening to the other.

Here are my 2 cents.

Let’s start with some facts:

Let’s review the circuits involved here. With the stock setup there are only two circuits involved:
1 - The solenoid activation circuit that goes from the battery through the ignition switch and any safety switches and then to the solenoid. Closing all switches completes the circuit to the solenoid.
2 - The starter motor circuit that goes from the battery along the battery cable to the external starter lug and through the switch inside the solenoid then to the starter motor.
(When the solenoid is activated, its internal switch then completes the starter motor circuit and activates the starter motor.)

With either the bosch or ford relay setup there are actually three circuits:
1 – The relay activation circuit. (Most of the original solenoid activation circuit becomes this circuit.) This circuit goes from the battery through the ignition switch and any safety switches and then to the relay.
2 – The Solenoid activation circuit. This circuit now goes from the battery through the new relay and to the solenoid.
3 – The starter motor circuit.
3a - With the bosch relay, this circuit is just like stock and goes from the battery along the battery cable to the external starter lug and through the switch inside the stock solenoid and then to the starter.
3b - With the ford relay this circuit still goes through the same route, except now there is a new switch along the path, the ford relay.
(Now when all the switches on the relay activation circuit are closed, the relay is activated which then closes the solenoid circuit, which activates the solenoid, which then closes the starter circuit and activates the starter motor.)

Let's isolate the starter and solenoid circuits and look at them separately with the two relay options.

First, the solenoid circuit:
With the bosch setup, the solenoid circuit now goes from the battery through the bosch relay and to the solenoid.
With the ford setup, the solenoid circuit now goes from the battery through the ford relay and to the solenoid.
Both of these options create a solenoid circuit with less resistance than the stock circuit wiring and these circuits can provide more current flow to the solenoid.
(With both of these options, the original solenoid circuit becomes a relay activation circuit that requires much less current flow.)

Now, the starter circuit:
The Ford relay is NOT giving the starter more current as some claim. Let’s compare the two setups. In the bosch setup, there is a battery cable directly from the battery to the starter. In the Ford setup, there is a battery cable that goes to the Ford relay and then to the starter. If anything, the starter gets very slightly less current with the Ford relay due to the resistance of the two extra connections and the contacts inside the ford relay. I know group 2 is now saying no, you are missing the fact that the relay also controls the starter, not just the solenoid, and gives the starter more current too. No, it doesn't. Just think about it. The stock solenoid still has to get the current from the external starter lug to the starter wiring. In either setup, a large battery cable connects to the external lug of the starter. This lug connects to nothing inside the starter until the solenoid is activated. The only difference is that with the Ford setup, the only time there is current at this lug is when there is also current at the solenoid.

The only difference in the starter circuit with the two setups is that with the ford setup the starter circuit also goes through the ford relay. The bosch setup only has one switch in the starter circuit, which is the switch inside the stock solenoid. The ford setup has two switches in the starter circuit, the switch in the stock solenoid and the new ford relay. With the Bosch setup, the starter lug is always hot. With the ford setup the starter lug is only hot when the relay is activated.

The shunt between the starter lug and the solenoid lug is NOT relieving the stock solenoid from making the connection to the starter motor as one post stated, and it is NOT bypassing the internal stock solenoid contacts as another post stated. The shunt does NOT change the starter circuit at all. The shunt only changes the solenoid circuit. With the shunt there is no need for a separate wire from the relay to the solenoid lug. With this setup, the battery cable from the relay to the starter lug is part of both the starter and solenoid circuits. Repeat – changing the solenoid circuit is the only thing shunt does, it doesn’t change the starter circuit at all.

With the ford setup, the switch inside the stock solenoid still has to route the current from the external starter lug through its internal contacts to the starter motor windings to make it turn. Think about it, current to the starter lug was never the issue to begin with. If it was, then using a screwdriver to short this lug to the solenoid would never have worked to solve the hot start problem.

The above are all simple statements of fact as far as I know. I don’t think anyone can argue with these. Take this for what you may. I hope these facts will help lessen the confusion of this whole debate for group 1.

Now for some opinions (Feel free to argue with these.):

I believe the ford setup is slightly superior to the bosch setup, but not for the reasons that group 2 has claimed. The advantage has nothing to do with the starter circuit or bypassing the stock solenoid contacts, as I’ve explained above, this doesn’t happen, and actually the starter motor circuit could have slightly more resistance with the ford setup. (But the starter circuit was never the problem.) The small advantage of the ford setup is that it will have less resistance in the solenoid circuit than the bosch setup will, period. The ford setup will have less resistance on the solenoid circuit simply because almost the entire circuit is made up of large battery cable. The only other part is the very short shunt wire. Some will argue that with the bosch setup the solenoid circuit only has a slightly longer small wire from the relay to the solenoid lug and that shouldn’t create much more resistance. But, there is also the wiring from the battery to the bosch relay. This wiring is smaller than battery cable and could be quite long depending on how it is setup. I think the key to a successful bosch relay install is to make sure that the wire from the battery to the relay isn’t too long and has good connections and isn’t too small. If these points are addressed, then I think the bosch setup will work fine and the difference in resistance of the two setups will only rarely come into play. (If the 3 gallon bucket holds all the water, does the 5 gallon bucket hold it any better? - Sometimes, on the rare occasion that you unexpectedly need 4 gallons instead of 3.)

Someone suggested using the Ford relay, but wiring it like the bosch setup would work just as well as wiring it the Ford way or using the Bosch relay. I would say this setup would fall in that very, very, very narrow range between the Bosch setup and the full Ford setup. The only aspect of this that matters is the slight change in the resistance of the solenoid circuit. To restate from above, having the relay control the starter circuit is no real advantage. If you ran battery cable to the input side of the relay and small wire to the solenoid lug, this setup would have slightly more resistance in the solenoid circuit than the normal ford setup because a longer section of the solenoid circuit now goes through a smaller wire just like the bosch setup. It would have slightly less resistance than the Bosch setup because there is still battery cable for the part of the circuit before the relay. If you ran smaller wire to the input side of the relay, like with the bosch setup, then it would have pretty much the same resistance in the solenoid circuit as the bosch setup and work about the same.

I personally use a Ford relay for several reasons, but not because I think it works much better than the bosch.
- I like the idea of not having a live connection at the starter when working under the car with metal tools. Ever accidentally touch a tool to this terminal and a ground? (I don’t even have to disconnect the battery to change the starter.)
- I rewired my whole car during a rebuild and just made this part of the plan. So changes to the stock wiring weren’t an issue for me.
- I use the input lug of the ford relay to attach other power feeds, such as my EFI power and power for extra fuse centers. This is much cleaner than having these go to the starter lug. (My battery is in the trunk, so going straight to the battery isn’t a good option.)
- There is only one wire going to the starter, which is slightly cleaner than two.

Okay so both relay options reduce the resistance of the solenoid circuit and provide more current to the solenoid and seem to solve the hot start problem. But why do we need the extra current during hot start?
Is it because the stock solenoid circuit has more resistance during the hot start than normal due to the heat? Or is it possibly a mechanical issue in the solenoid due to the heat that causes it to require more force to activate the solenoid and therefore more current? If it is a mechanical issue in the solenoid, that would explain why a heavy duty solenoid can sometimes also solve the problem. Also, why would a heat shield sometimes solve the problem of if it was only due to the heat causing extra resistance in the circuit? This shield would keep the solenoid cooler, but not the rest of the wiring. I really don’t know the answer to this question, my guess is that both of these come into play, sometimes one more than the other.

Oh wait, I forgot about the argument about the ford part being a solenoid or a relay.

A relay is a switch that controls one electrical circuit with another circuit using some type of internal electromagnetic switch.
A solenoid uses an electromagnet to create linear motion of the core.

The Ford part is actually a relay that just happens to contain a solenoid as its internal switch. The linear motion of the solenoid in this case causes two other contacts to be connected. The fact that this is one circuit controlling the opening and closing of another circuit makes the whole ford part a relay.

The reason some claim it isn’t a solenoid, is that a solenoid usually causes linear movement (like when your power door locks move or when the GM solenoid moves the starter gear). but with the ford relay there is no external movement, so as a whole it isn’t really a solenoid, it’s a relay. But as described above, there is a solenoid inside the assembly and the movement happens internally.

Actually, the only real difference between the ford relay and the bosch, other than the size and current capacity, is in the way the controlling circuit activates the controlled circuit. With the ford relay it is activated via contacts controlled by an internal solenoid. With the bosch relay, the controlled circuit is activated with some other type of electromagnet switch that also moves a set of contacts, but in a slightly different way.

Thoughts to ponder: Why do newer starter also solve the problem? Do they just require less current to activate the solenoid? Are their solenoids just less affected by the heat? Someone else can tackle this one.

Whew. I think I’ll go soak my fingers in some ice water.

Ray

PS: Most of the above was alluded to in various other posts before in this thread. And I don’t think for a minute I’m the only one that understands this. I think there is just a lot of frustration trying to convey this stuff in writing. Onofakind67 stated the basic concepts above in one of his posts in a quick and to the point format. But sometimes quick and to the point just doesn’t work. (And I think that by that post the group 2 folks weren’t listening to him much.) (I disagree with him on the thought that there is no way that heat in the solenoid could be causing a mechanical bind that contributes to the problem. I don’t know that it does, but there seems to be some evidence that this could be a contributing factor, and I can’t just dismiss it as a possibility. And maybe it isn’t a mechanical issue, but a wiring resistance issue in the solenoid that the heavy duty solenoid doesn’t suffer from.) (But I’m not an engineer or anything. All of the above is just based on simple logic.)

Wow, what a debate! It looks like there are five types of people reading this post:
1-Those who want to know if the Bosch relay is good enough or if the Ford relay (“solenoid”) is needed. (Or if the heavy duty solenoid alone will help.)
2-Those who are convinced the Ford part is required. (And just don’t want group 1 wasting their time on other options that won’t work.)
3-Those who are convinced the Bosch relay will solve the problem. (And just don’t want group 1 wasting their time on options that are overkill or don’t work.)
4-Those who believe that the heavy duty solenoid is all that is needed. (And just don’t want group 1 wasting their time on options that are overkill.)
5-Those who are just enjoying (or frustrated by) watching groups 2 and 3 argue their points, knowing each opposing group isn't really listening to the other.

Here are my 2 cents.

Let’s start with some facts:

Let’s review the circuits involved here. With the stock setup there are only two circuits involved:
1 - The solenoid activation circuit that goes from the battery through the ignition switch and any safety switches and then to the solenoid. Closing all switches completes the circuit to the solenoid.
2 - The starter motor circuit that goes from the battery along the battery cable to the external starter lug and through the switch inside the solenoid then to the starter motor.
(When the solenoid is activated, its internal switch then completes the starter motor circuit and activates the starter motor.)

With either the bosch or ford relay setup there are actually three circuits:
1 – The relay activation circuit. (Most of the original solenoid activation circuit becomes this circuit.) This circuit goes from the battery through the ignition switch and any safety switches and then to the relay.
2 – The Solenoid activation circuit. This circuit now goes from the battery through the new relay and to the solenoid.
3 – The starter motor circuit.
3a - With the bosch relay, this circuit is just like stock and goes from the battery along the battery cable to the external starter lug and through the switch inside the stock solenoid and then to the starter.
3b - With the ford relay this circuit still goes through the same route, except now there is a new switch along the path, the ford relay.
(Now when all the switches on the relay activation circuit are closed, the relay is activated which then closes the solenoid circuit, which activates the solenoid, which then closes the starter circuit and activates the starter motor.)

Let's isolate the starter and solenoid circuits and look at them separately with the two relay options.

First, the solenoid circuit:
With the bosch setup, the solenoid circuit now goes from the battery through the bosch relay and to the solenoid.
With the ford setup, the solenoid circuit now goes from the battery through the ford relay and to the solenoid.
Both of these options create a solenoid circuit with less resistance than the stock circuit wiring and these circuits can provide more current flow to the solenoid.
(With both of these options, the original solenoid circuit becomes a relay activation circuit that requires much less current flow.)

Now, the starter circuit:
The Ford relay is NOT giving the starter more current as some claim. Let’s compare the two setups. In the bosch setup, there is a battery cable directly from the battery to the starter. In the Ford setup, there is a battery cable that goes to the Ford relay and then to the starter. If anything, the starter gets very slightly less current with the Ford relay due to the resistance of the two extra connections and the contacts inside the ford relay. I know group 2 is now saying no, you are missing the fact that the relay also controls the starter, not just the solenoid, and gives the starter more current too. No, it doesn't. Just think about it. The stock solenoid still has to get the current from the external starter lug to the starter wiring. In either setup, a large battery cable connects to the external lug of the starter. This lug connects to nothing inside the starter until the solenoid is activated. The only difference is that with the Ford setup, the only time there is current at this lug is when there is also current at the solenoid.

The only difference in the starter circuit with the two setups is that with the ford setup the starter circuit also goes through the ford relay. The bosch setup only has one switch in the starter circuit, which is the switch inside the stock solenoid. The ford setup has two switches in the starter circuit, the switch in the stock solenoid and the new ford relay. With the Bosch setup, the starter lug is always hot. With the ford setup the starter lug is only hot when the relay is activated.

The shunt between the starter lug and the solenoid lug is NOT relieving the stock solenoid from making the connection to the starter motor as one post stated, and it is NOT bypassing the internal stock solenoid contacts as another post stated. The shunt does NOT change the starter circuit at all. The shunt only changes the solenoid circuit. With the shunt there is no need for a separate wire from the relay to the solenoid lug. With this setup, the battery cable from the relay to the starter lug is part of both the starter and solenoid circuits. Repeat – changing the solenoid circuit is the only thing shunt does, it doesn’t change the starter circuit at all.

With the ford setup, the switch inside the stock solenoid still has to route the current from the external starter lug through its internal contacts to the starter motor windings to make it turn. Think about it, current to the starter lug was never the issue to begin with. If it was, then using a screwdriver to short this lug to the solenoid would never have worked to solve the hot start problem.

The above are all simple statements of fact as far as I know. I don’t think anyone can argue with these. Take this for what you may. I hope these facts will help lessen the confusion of this whole debate for group 1.

Now for some opinions (Feel free to argue with these.):

I believe the ford setup is slightly superior to the bosch setup, but not for the reasons that group 2 has claimed. The advantage has nothing to do with the starter circuit or bypassing the stock solenoid contacts, as I’ve explained above, this doesn’t happen, and actually the starter motor circuit could have slightly more resistance with the ford setup. (But the starter circuit was never the problem.) The small advantage of the ford setup is that it will have less resistance in the solenoid circuit than the bosch setup will, period. The ford setup will have less resistance on the solenoid circuit simply because almost the entire circuit is made up of large battery cable. The only other part is the very short shunt wire. Some will argue that with the bosch setup the solenoid circuit only has a slightly longer small wire from the relay to the solenoid lug and that shouldn’t create much more resistance. But, there is also the wiring from the battery to the bosch relay. This wiring is smaller than battery cable and could be quite long depending on how it is setup. I think the key to a successful bosch relay install is to make sure that the wire from the battery to the relay isn’t too long and has good connections and isn’t too small. If these points are addressed, then I think the bosch setup will work fine and the difference in resistance of the two setups will only rarely come into play. (If the 3 gallon bucket holds all the water, does the 5 gallon bucket hold it any better? - Sometimes, on the rare occasion that you unexpectedly need 4 gallons instead of 3.)

Someone suggested using the Ford relay, but wiring it like the bosch setup would work just as well as wiring it the Ford way or using the Bosch relay. I would say this setup would fall in that very, very, very narrow range between the Bosch setup and the full Ford setup. The only aspect of this that matters is the slight change in the resistance of the solenoid circuit. To restate from above, having the relay control the starter circuit is no real advantage. If you ran battery cable to the input side of the relay and small wire to the solenoid lug, this setup would have slightly more resistance in the solenoid circuit than the normal ford setup because a longer section of the solenoid circuit now goes through a smaller wire just like the bosch setup. It would have slightly less resistance than the Bosch setup because there is still battery cable for the part of the circuit before the relay. If you ran smaller wire to the input side of the relay, like with the bosch setup, then it would have pretty much the same resistance in the solenoid circuit as the bosch setup and work about the same.

I personally use a Ford relay for several reasons, but not because I think it works much better than the bosch.
- I like the idea of not having a live connection at the starter when working under the car with metal tools. Ever accidentally touch a tool to this terminal and a ground? (I don’t even have to disconnect the battery to change the starter.)
- I rewired my whole car during a rebuild and just made this part of the plan. So changes to the stock wiring weren’t an issue for me.
- I use the input lug of the ford relay to attach other power feeds, such as my EFI power and power for extra fuse centers. This is much cleaner than having these go to the starter lug. (My battery is in the trunk, so going straight to the battery isn’t a good option.)
- There is only one wire going to the starter, which is slightly cleaner than two.

Okay so both relay options reduce the resistance of the solenoid circuit and provide more current to the solenoid and seem to solve the hot start problem. But why do we need the extra current during hot start?
Is it because the stock solenoid circuit has more resistance during the hot start than normal due to the heat? Or is it possibly a mechanical issue in the solenoid due to the heat that causes it to require more force to activate the solenoid and therefore more current? If it is a mechanical issue in the solenoid, that would explain why a heavy duty solenoid can sometimes also solve the problem. Also, why would a heat shield sometimes solve the problem of if it was only due to the heat causing extra resistance in the circuit? This shield would keep the solenoid cooler, but not the rest of the wiring. I really don’t know the answer to this question, my guess is that both of these come into play, sometimes one more than the other.

Oh wait, I forgot about the argument about the ford part being a solenoid or a relay.

A relay is a switch that controls one electrical circuit with another circuit using some type of internal electromagnetic switch.
A solenoid uses an electromagnet to create linear motion of the core.

The Ford part is actually a relay that just happens to contain a solenoid as its internal switch. The linear motion of the solenoid in this case causes two other contacts to be connected. The fact that this is one circuit controlling the opening and closing of another circuit makes the whole ford part a relay.

The reason some claim it isn’t a solenoid, is that a solenoid usually causes linear movement (like when your power door locks move or when the GM solenoid moves the starter gear). but with the ford relay there is no external movement, so as a whole it isn’t really a solenoid, it’s a relay. But as described above, there is a solenoid inside the assembly and the movement happens internally.

Actually, the only real difference between the ford relay and the bosch, other than the size and current capacity, is in the way the controlling circuit activates the controlled circuit. With the ford relay it is activated via contacts controlled by an internal solenoid. With the bosch relay, the controlled circuit is activated with some other type of electromagnet switch that also moves a set of contacts, but in a slightly different way.

Thoughts to ponder: Why do newer starter also solve the problem? Do they just require less current to activate the solenoid? Are their solenoids just less affected by the heat? Someone else can tackle this one.

Whew. I think I’ll go soak my fingers in some ice water.

Ray

PS: Most of the above was alluded to in various other posts before in this thread. And I don’t think for a minute I’m the only one that understands this. I think there is just a lot of frustration trying to convey this stuff in writing. Onofakind67 stated the basic concepts above in one of his posts in a quick and to the point format. But sometimes quick and to the point just doesn’t work. (And I think that by that post the group 2 folks weren’t listening to him much.) (I disagree with him on the thought that there is no way that heat in the solenoid could be causing a mechanical bind that contributes to the problem. I don’t know that it does, but there seems to be some evidence that this could be a contributing factor, and I can’t just dismiss it as a possibility. And maybe it isn’t a mechanical issue, but a wiring resistance issue in the solenoid that the heavy duty solenoid doesn’t suffer from.) (But I’m not an engineer or anything. All of the above is just based on simple logic.)

Wow Ray, you have a lot of patience to make a long post like that...or maybe too much time on your hands :) I received a clarification on the hi temp solenoids, and mechanical issue are addresses as well as better heat insulation of the windings. To sum it up.... instead of going to the other side and using Ford parts and reinventing the wheel, just try one. I can't remember the price but it was under $25. As long as these threads are entertaining , educational and NOT insulting, I welcome them.

I found this thread yesterday and never read the earlier posts, but found out quickly this was a hornets nest. BTW would someone please try one of these, so I can prove my point:)

Ray, that was good.

So... To make the "ford solenoid" work like Dave wants it to work, we need to do the following:

Make our piece of copper bigger, and attach it to ALL THREE terminals on the solenoid. The "S" terminal, the BAT terminal, AND the bottom lug which connects to the starter motor! This setup WOULD completely bypass the stock solenoid, other than it's function of throwing the bendix into the flyweel.


Just to add a lil more to this, there were ZILLIONS of GM cars produced using this same exact starter motor and solenoid design, the same wire sizes, and the same or similar switches and connectors in the circuit.

Of these ZILLIONS of cars, a good percentage of those that are left were at some point equipped with headers, as well as modified engines.

The vast majority of these continue to start just fine.

While "heat soak" is a real problem that really exists, if you have it, then something or some combination of things in your starter circuit is BROKEN, period. This stuff was well designed and properly sized, and if it is right, it will work, every time.

If your switches are good, your connections are good, your wires are good, and your starter is good, your car will always start.

Ray, that was good.

So... To make the "ford solenoid" work like Dave wants it to work, we need to do the following:

Make our piece of copper bigger, and attach it to ALL THREE terminals on the solenoid. The "S" terminal, the BAT terminal, AND the bottom lug which connects to the starter motor! This setup WOULD completely bypass the stock solenoid, other than it's function of throwing the bendix into the flyweel.


Just to add a lil more to this, there were ZILLIONS of GM cars produced using this same exact starter motor and solenoid design, the same wire sizes, and the same or similar switches and connectors in the circuit.

Of these ZILLIONS of cars, a good percentage of those that are left were at some point equipped with headers, as well as modified engines.

The vast majority of these continue to start just fine.

While "heat soak" is a real problem that really exists, if you have it, then something or some combination of things in your starter circuit is BROKEN, period. This stuff was well designed and properly sized, and if it is right, it will work, every time.

If your switches are good, your connections are good, your wires are good, and your starter is good, your car will always start.

I agree, but just to add something, when headers are used or heatshield are discarded (big block) you may need a little help. Also solenoids do breakdown whether it be electrically (insulation) or electro mechanically (toleranced) . BTW I have only experienced this problem with big blocks. My survivor 69 L34 has never been touched and it function perfectly under any temperature condition. Yes these cars have flaws based on the technology they used back in the day, but I like the challenge of fixing them and preserving them to the best of my ability.

ray, nice post...jim too.i figure you count me in the argumentative catigory 2...not really...i much prefer the ministarter, but whatever...the solenoid/relay thing is an interesting way to see it, and if originally explained in this manor, would have been easier to accept...ofcorse, the parts stores have been calling it a solenoid since christ was a corporal, and there is a solenoid incorporated in its design...but again, symantics,whatever...the heavy duty solenoid sounds like a reasonable solution, although i`ve never used it...as shaugs, and ray, i kinda stick with what works, and for me, thats a mini...i`ve seen heat soak solved by using header wrap, shields, extra solenoids/relays, different starters,adjusting timing, adjusting fuel mixture,redesigning exhaust for less back pressure to help heat escape, and prolly more that i cant think of right now...this post has beaten the hell out of 1 dead horse for sure...lmao...

IMHO, there are all sorts of things that can cause a starter to not work correctly. I think there have been several good suggestions made here. But for some reason people think of this as a single problem with a best solution. My advice is if you have a problem with your starter motor, get out a schematic, a volt meter, and have your significant other attempt to start it while you take measurements and find the real problem. Gawd...I din't think this topic could have spun up like it has.

kustomwerker - I didn't mean the groups as insults to anyone. I actually was trying to lighten the atmosphere with a little humor. Guess I messed that up. I was also trying to convey that I felt that everyone had genuine concerns for the people in group 1 that wanted guidance and they wanted to give them the best possible advice. They were each convinced of their thoughts on the subject through their own past experiences and wanted to share that knowledge. My point was that they were all kinda right. It's just that sometimes human nature is to care about the symantics and get focused on that arguement instead of the big picture. And usually in a debate like this, there is substance to all sides and just some gray areas in the details. (And sometimes a little more focus on stating your case than listening to the other side.) And then there is the frustration when you can't make someone else see your logic, and you get hung up on that. I sure hope I didn't make any enemies here with the group thing, I really didn't mean it in a bad way. Like groups 2-4, my main concern was getting helpful information to group 1.

JimM - Yes, now that would bypass the switch inside the solenoid.

shaugs - no, not much free time on my hands. I'm now behind on work. But once I started the post it turned into a monster. I tend to over explain, but sometimes that actually helps.

dnult - I hate to say this, but I just reviewed all of your posts on this thread, and that was your first post that didn't criticize onovakind's suggestion and your most useful post yet. After reading my post with an open mind, do you still stand behind all your previous posts? (Okay kustomwerker, maybe I just made one enemy. but sometimes the truth hurts. But I really hope I didn't make an enemy, just open eyes.)

naw,man...i got thick skin...i can take it...lmao...fact is, techs find what works for them, and stay with it...point blank...cooling and heating stuff that works in arizona is different than in ct because of surrounding conditions...my problem with running a little hot in my 79 would be a much bigger problem in florida or arizona...but in ct, i can deal with it without too much fuss...daves fix obviously worked for him at some point, and onovakinds fix works for him...they`re all valid in their respective ways...i use mini`s because they dont care about heat or compression...also, we run a blown 383 locked out at 30 degrees, so the mini is the way to go for us on the nova...but in a show, it could cost you big to see a mini in there, or a ford solenoid, or even a bosch relay...therefore, shagus`s hipo solenoid may be the way to go...whatever gets your ride down the road...to tell the truth, the whole debate thing is kinda nice sometimes, cuz you get all worked up, and it really gets you thinking, and more importantly, learning...the biggest problem i have with these forums is that you cant tell someone`s demeanor from their post...sometimes i come off way harsh and really dont mean to, but i`m not a people person...i dont put things into words very well...i can sound dicky without meaning it...onovakind seems to have the ability to stir me up pretty easily too...lmao...but i dont take it to heart, and i hope he doesnt either...i dont have ill will toward anyone on the site,although i can get a little mouthy...but you put a pile of rodders,customs,bikers,and purists in the same room, and there is bound to be a little clashing here and there,right...

I like a debate as much as anyone, gets the blood moving and all.

In this case, we were trying to help someone who's car wouldn't start, one of the most frustrating and publicly embarassing afflictions an old hot rod can have.

People got carried away, arguing symantecs, possibly misunderstanding each others suggestions, and argueing for the sake of argueing.

Most of it was little help to the guy who's car wouldn't start.

JimM - Yes, now that would bypass the switch inside the solenoid.


That's the way it has worked in my case, but hasn't been needed in my Camaro yet.:D

...dnult - I hate to say this, but I just reviewed all of your posts on this thread, and that was your first post that didn't criticize onovakind's suggestion and your most useful post yet. After reading my post with an open mind, do you still stand behind all your previous posts?

I'm not sure what you mean by "that was your first post...criticizing onavakind's suggestions...". I don't recall flaming onovakind, though I am frustrated with this thread. I'm not selling anyone anything. I can't put hands on the OP's car so as usual, we speculate about the real issue. Perhaps someone has their feathers ruffled by being corrected for publishing misinformation. Was that me? I certainly hope not.