Today I installed an Accel Super Coil, 8mm wires, platinum plugs, and new cap into my 77RS. When I gave it a test drive I noticed a nice performance increase (mostly due to getting rid of the old cap I had on before) but I also noticed that the car idles horribly at 600 RPMs now. About once a second the engine will feel like it kicks and the car will vibrate. The tach will drop down 100 or 200 RPMs then bounce back up until the next kick. If I take it out of gear the tach will rise to 900 RPMs and the problem goes away.

I don't know if this is related so I'll add it anyway: I installed an Aluminum Manifold & 600CFM Edelbrock carb a couple of months ago and have had a similiar vibration at freeway speeds since altough much less pronounced. (It actually sounds more like the warp drive on star trek).

Any ideas on what I did wrong?

Thanks in advance,
Steve

Basic first thought, check the firing order. Most common mistake is 5/7 swap. Just the first step.

Well I checked the order, verified that all of the wires were on tight and didn't come up with anything. I did notice something today though. It only does this when the temp goes above 190 degrees. Givin this last piece of information I'm starting to wonder if it is related to the new coil or not. Ideas??

Thanks in advance,
Steve

I think I can help you. I had the same exact thing happen to me in my 67 SS350. It's the plugs. I was replacing my spark plugs and decided to go with Bosch Platinums. Put them in and the car seemed to get a small boost initially. But, when the engine reached operating temperature, the idle went all to hell and the car hesitated, sputtered, puked, etc like crazy. Since I had only replaced one thing, the plugs, I knew it had to be them. So I took the platinums out and put new AC Delcos back in. Sure enough, the car ran great (better than it ever had before, I might add). So I took the platinum plugs back to Auto Zone and a different guy than the one who sold them to me told me, "I have no idea why he told you the platinum plugs would work in your car. You can't put platinums in older small block chevys, the sparks aren't big enough or hot enough to ignite the larger quantities of gas." Makes sense to me, considering the minute size of the electrodes on those platinum plugs. Give it a try....replace your plugs with AC Delco and I'd be willing to bet you'll be pleasantly surprised. Well, maybe not pleasantly, since you shelled out $5 a pop for useless platinum plugs.

A couple of more things to consider:

There may be a need for a plate under the carb, depending on just which intake/carb setup you have. Edelbrock performer mainfolds are made for Q0jets, Performer RPMs for square flange carbs. I have seen the RPM mianifolds need the plate as well, to cover up small places that don't close on the carb to manifold mating up. Gives a slight vacuum leak.

Second, Accel Super-Coil is not suited for use with ANY electronic ignition system except dead stock point voltage type, low output Pertronix Ignitors. Unilite systems don't even like them. The coil comes with a separate ballast resistor, and needs to be used with any other resistor to perform right. These coils do nothing but give trouble with larger output HEI or CD ignition systems, and are simply useless in my book.

I use the round Super-Stock coils, without resister, for HEI and CD use without problems, and with stock vehicle point system resistor only for point systems.

The Super-Coil was designed for use with point systems only, should be run that way.

I planed on checking for vacum leaks later on today. So I'll let you guys know.

The carb/manifold combo is a Edelbrock 600CFM Square Bore #1406
Edelbrock Perfromer #3701

The plugs I used are AutoLite Platinum's which I haven't had problems with in the past, I'm thinking I might want to inspect & reseat the plugs.

On the coil side of things... I'm under the impression that the stock ignition system on a my camaro does not need it. I'll check coil positive to make sure it's between 8 & 10 volts.

Thanks for the advice,
Steve

IgnitionMan,

Curious to understand more why the Accel coil is not a very good unit to use with electronic ignitions. I'm not going to approach you with "...well, I'm using a MSD 6 series box and I have no problems, so you're full of it...", because sometimes a component can have a marginal failure condition which may be apparent on one setup and not another.

For some reason (perhaps I was feeling frugal at the time) I opted for this coil, even though the rest of my ignition system is MSD (box, distributor, wires). Since I have only used this coil, I cannot say that I've had a performance delta of any kind.

One interesting problem that I've noticed, only during the past 1k miles or so with a setup that has not changed, is (or what appears to be) vapor lock. Have you ever seen the electrical characteristics of the Accel coil change dramatically as a function of heat?




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http://www.geocities.com/dmdirks/Automotive.html

RacerX, sure have. they get internal windings layer shorts, making them change the amount of delivered voltage and signal to make the things continue to work.

Worst case scenario is where the coil gets a jolt of serious voltage from a spike, then layer shorts, makes the module overwork to keep up with the damaged coil's requirements to do its job, module failure becomes cronic and then peolpe hear how bad this or that system is, when all the time it was a damaged coil settin the entire system into chaos.

The Super Stock round series coils from Accel are OK for Cd and HEI useage, wound to work with both ballast resistor for point and low output stock replacement ignitions, like Pertronix and Unilite, unresisted HEI, MSD, other CD systems.

Super Coil is only inte4nded to be used for point and maybe Pertronix, Unilite WITH the reisitor in place, and in some apps, the added resistor sent with the Super Coil also.

Over the years, many parts people have started many wive's tales about useages of some parts, and this has even trickled back to some tach lines within manufacturer's houses, making the tale into fact, only it doesn't work that way, most situations.

Super Coils are also super sensitive to temperature rising, heat well-up and resistance within their electronic environment, and can do some strange things when allowed to get overheated. Some things colis do just make engines run crappy, not all coils go away and stop the car. They can simply produce some strange symptoms, like carburetion off, strange timing curve changes, overheating, and more.

Super coils like being mounted nose up, like all other oil filled coils, to ensure the windings are fully covered with heat transfering oil they are filled with. Mounting the coil on its side or nose dwon,can expose the windings partially to the air vloume inside them, coil and system (module) overheating and failure may well result from this incorrect mounting.

IgnitionMan

What is the part number of the plate that you spoke of. It's not the insulator type is it and what is your thoughts on the direct replacement accel for the factory HEI dist. ?

71 Camairo

Hmmmm...

IgnitionMan, your theory is intriguing me, especially since my coil is has always been mounted sideways. Since I do not have another coil laying around the garage, I believe I will purchase the proper coil from MSD. This will also ensure that I don't get caught in a situation where the manufacturer won't touch a technical issue unless all the components are theirs.

Thanks for the advice.



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http://www.geocities.com/dmdirks/Automotive.html

71camaro, post your e/mail address and I will send you information on another HEI alternative you might be interested in.

RacerX, might be that the coil is coming into its dieing time, some take longer than others to go away. I have seen lots of Super Coils on their sides, and most of them ran super hotter than mounted in an upright position. some lived long, some went away fgairly soon, just dependfs on the coil, I guess. Really don't have a concrete answer on this event.

Just my observations.

[This message has been edited by IgnitionMan (edited 05-01-2000).]

IgnitionMan


Any help is appreciated. Ignition systems is one of my weak points and definately need some in put. Thanks


71 Camairo

I have seen that the quality control must be lacking on the Accel coils. I have sold some that people have loved and then again I have sold some that come back in a week for some type of problem. Mostly leaking oil or some that have cracked.
I also know that I have sold a few MSD Blaster coils that have never come back.
I use a Crane PS-91 coil with a HI6 and an XR700 electronic conversion setup. Great stuff.

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Tim (http://www.geocities.com/sixt7ssrs/CAR2.jpg)
67 ss/rs (http://www.geocities.com/sixt7ssrs2/Mvc-562f.jpg), MODIFIED (http://www.geocities.com/sixt7ssrs/main.html)
Tim's Homepage (http://www.geocities.com/sixt7ssrs)
AOL-IM = sixtsevnss

I use the Accel Super-Stock series round coils, 8140, 8140C (never the Super Coil), same construction as MSD 8200, 8282 Blaster II, III coils, most places, cost less.

Make surre the coil is wired correctly. The car will still run if positive is hooked up to negative at the coil but it will not run very well.

Raymond's dead right. Funny to see spark travel from the ground to the center electrode, backwards.

IgnitionMan - I'm running a Unilite distributor and matching coil, MSD 6AL box and wires. I've had some weird symptoms like you and others have mentioned. After trying numerous other things I'm about ready to switch to a different coil and distributor. I like the MSD stuff but it's pricy - what's your recommendation?

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Scott
'69 400SB, Richmond 5-speed; '99 HD Road King Classic
www.geocities.com/sdenning1 (http://www.geocities.com/sdenning1)

Nothing really wrong with your system, please post all the symptoms so we can get right to diagnosis and fix.

I'nm getting misses - most notably under hard acceleration and around 3 - 4k RPM. It's worse in 1st gear and better somewhat in the remaining gears. Sometimes (not often in 1st) it will revive or pull through the miss - other times it's as if you hit the rev limiter. I've also had some difficulty holding an idle - it tends to wander around and wants to be either at 600 or 1200 - but not 900. I was fouling plugs quite a bit prior to the MSD box but that seems to have gone away now.

The motor is a 400 SB, 10-1, Comp Cams 274 Extreme Energy cam (230/236 at .050), RPM intake, heads, and 750 (or 600) carb.

It's worth noting that there is a weird mechanical tapping sort of sound from the #2 cylinder head area that comes and goes. My (brother-in-law) mechanic believes it's a piston just barely touching the head. I suppose if this is correct it could certainly spoil things during acceleration and might show up as a strong "miss"? I'll pop the valve cover and the head soon to try to figure this out.

Nevertheless, even with a previous motor I was getting a miss on acceleration. I've changed motors, carbs, wires, etc. - just about everything but the distributor and coil. After seeing the various posts on Unilites and coil problems I wondered if I shouldn't go ahead and swap. These units are probably a good 10 - 12 years old but spent the vast majority of that time waiting thru 2 restoration efforts.

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Scott
'69 400SB, Richmond 5-speed; '99 HD Road King Classic
www.geocities.com/sdenning1 (http://www.geocities.com/sdenning1)

Might try substututing a coil of known good performance first. If that isn't a help, tune the Unilite up, and have the curve checked.

Thanks! I'll give it a try.