Well guys, I've been looking through past posts about drilling the holes into the thermostat to allow water.. air to flow through the engine during warm up to help with air lock problems.
I've been dealing with this heating issue when I put the car under load, either by heavy foot, pulling a hill, or highway driving. During town driving it runs around 185 deg, in the other situations it will heat to 200 deg, and usually remain in that temp range.
My car has a stock water pump, 180 deg thermostat, stock shroud, flex fan, secondary 13" Spal electric fan, automatic transmission with cooler in radiator tank.
With the temp at the 200 deg range, I switch on the electric fan, and doesn't drive the temperature down, so thinking it's not an air flow issue.
Seem to have decent water flow in the radiator when veiwing with the car running and cap off.

A friend suggested seperating the transmission cooling and engine cooling systems and the problem should go away. So I ordered the B&M cooler last night.

What's the advice from the experts? Should I first drill the thermostat, and drive a couple of times to see if I have a vapor lock issue? Thanks for any help. :yes:

Drilling holes may help. Using a high flow thermostat, simular to MRG-4864(?), might help also. Having a larger crankshaft pulley to overspeed the w/pump by 30% might help also.

Advancing timing, say running full time vacuum to the vacuum cannister, would help.
However, later model vehicle of any type have a higher thermostat, 195°F, to run hotter since you didn't give year of vehicle, tend to run hotter.

A closed leak-free coolant system is the key, tight upper rad hose will tell this, hard to squeeze, may be ahigher rad cap, 18-20 PSi cap to prevent boilover when engine is stopped after a run will help.

200 deg. is not HOT. Is your gauge accurate? Does the car boil over?
Dale

Sorry about not giving more details on year and engine. It is a 67 with mild 327 engine, TH350 transmission, 12 bolt eaton posi running 342 gear.
I think the temp gauge is somewhat correct since it did boil over at 200 deg. I also ordered new autometer gauges that should be here soon with the trans cooler.
I know its not a complete waste of money on the trans cooler since it will benifit trans life, but will it help the heat issue?

Like all the above,
Also you should drill the 2-small holes in the T-stat, but also check it in a pot of water to check when it starts to open... Like Everette said timing advance curve, what ignition do you have and how is it set up with initial and cruze and total timing.

Idon't think the oil cooler in the rad will be detrimental as coolers have been in radiators for a long time. However, a looser than stock convertor will heat up the oil in a heartbeat and contribute to engine coolant temp.

When you do get the cooler, you can add it in series with the OE cooler, tap off the top line from rad to the bottom tube of the add-on cooler. This hookup fills the add-on cooler from the bottom to eliminate air pockets in the cooler itself. Only item is this is adding the add-on cooler after the OE cooler, so there won't be any additional reduction of heat to engine coolant, unless you hook the add-on cooler by itself or before the OE cooler.

If boilover is occurring at 200°F, then another problem is present, at least you need a higher pressure cap, OE spec is 15-16 PSI. Or the gauge is incorrect, shoot the thermo housing for a better read of coolant temp, won't be exact , but give an idea. Maybe have the rad cleaned because most every V8, 327 & 350 did not overheat with 180°F stat and even with a 6-cyl radiator.

Thermostat working good? You should feel the 'heat' when it opens from both the upper rad hose and the air being pulled through the radiator, this gives a mental idea of gauge calibration if the thermo is working. In fact, you might even pull the stat and boil it in a pan of water just to make sure. Starts to open at its factory setting and be completely open 10° F later. Meat thermometer & A/C thermometer are good gauges kindda, don't let the tip touch the bottom of the pan, keep it in the water.

Do you see any bubbles in the coolant as it is running? This is a sign of combustion gases from a leaky head gasket. The cleanest spark plug will be the culprit cylinder, might have a green tint to the porclein.

Fan belt tight and not slipping?
Fan blades within a 1/2" of the shroud?
No dirt/trash/rocks in the rad fins? Radiator fins straight? Use a rad fin comb to straighten or get alot of patience and use a small screwdriver to straighten them out.
Timing advanced? Retarded timing will tend to run hotter.
Lean fuel mixture will run a little hotter.
Does engine temp reduce some with max heat selected? Too small radiator or partial plugged.

Thank you guys for the help!
I am running the MSD Ready to Run Billet distributor with vacuum advance. All the shipped with timing springs are currently installed. Just stuck it in and went. The initial timing is set at 10 BTDC. Not really clear on how to check the total timing..
The radiator cap is a new one with 16# setting, radiator is new also.

I have a hand held temperature gun, so I ran the motor to look at the temps. What was weird, the temp gauge in car got to 180 deg, the thermostat seemed to open based on the upper rad hose getting hot and flow increasing to the right side radiator tank. I had a few air bubbles but not to much. When I shot the temperatures on the motor this is what I got.
Intake manifold area near thermostat unit was 180 deg.
Left side radiator tank was 176 deg.
Right side radiator tank was 142 deg.
Thermostat housing was at 126 deg??
The 126 can't be right can it? Would this indicate an air void? :confused:

The new gauges and cooler arrive thursday, will drill the holes in the thermostat when drained for temp gauge install. Should I advance the timing up until it pings?

and held temp guns can give bad readings if your aiming at a reflective surface.
did you get the radiator backflushed at the radiator shop?
whats the radiator size 2 core or 3 core?
one thing you gotta verifiy is that the lower hose isnt collapsing when you gun the throttle!
if it is it requires a spring inside the hose to prevent that.

The initial timing is set at 10 BTDC. Not really clear on how to check the total timing..

The 126 can't be right can it? Would this indicate an air void? :confused:Bring your h/bal mark to 10° on the scale, mark the h/bal at 0° and label 10°, rotate h/bal CCW until new mark is at scale 10°, mark again at scale 0° and label 20°, rotate new 20° to scale 10°, mark h/bal again and label 30°, rotate h/bal CCW to new 30°, mark and label 40°. Now you have a makeshift 40° to 0° BTDC scale.

Disconnect vacuum advance line and run engine up every 500 rpm's and make a table of how much mechanical advance the dist makes until it stops moving, usually around 3500 rpm. Hookup vac line and take a reading of vacuum advance. Now look at table made and the last timing result is total mech timing at WOT, maybe around 34° to 38° BTDC. Mech adv will be the total taken minus initial timing. Vac advance setting will be added to mech reading at cruise, a lower rpm.

The reading of thermo housing of 126°F is bogus, as suggested, a reading from a reflective surface. Believe the intake reading of 180°F.

Some lower hoses come with a construction not needing the spring as with older hoses.

You do have good differential temp reading from the two tanks, 34°F. Engine shouldn't be running hot, at least at idle. Road travel will tell the story, more work, more heat generated. New gauges will tell.

Your present timing should be fine.

I wonder if your running a bit too lean or rich after time things get heat soaked but it takes time for that to come up.Around town you are at idle from time to time and changing loads. On the highway that constant speed will produce a different effect re heat. Also keep in mind if you have a road draft tube the radiator will spit out when hot if its filled to the top. They ride just a bit low normaly. A over flow container could be all your problem is. 200 * isnt that hot. Just some thoughts for ya

Good point about the reflective surface. It is a chrome housing.

The radiator is a 3 core and new. I appear to have decent flow across to right side tank. Don't think it's got any issues, but have been wrong before. I will be checking for a collapsing hose tonight. Thank you for the additional check.

Everett, Great read on explaining how to figure out the total timing! Even I can understand it when its put into simple text. I've read posts where people are talking about total timing, but didn't really understand how to get it. Thank you

Good point about the reflective surface. It is a chrome housing.Remove and chuck it as far as you can throw it. Replace with a known quality alum housing.

Everett, Great read on explaining how to figure out the total timing! Even I can understand it when its put into simple text. I've read posts where people are talking about total timing, but didn't really understand how to get it. Thank youYou're welcome. Mark the h/bal as such and it will put you in the ballpark and you can use your regular timing light - dun't need no stinkin' dialback timing lite........

[QUOTE=I will be checking for a collapsing hose tonight. Thank you for the additional check.
[/QUOTE]
make sure your up to temp and thermostat is open or else you wont see the hose collapse

I use a several strips of black tape on reflective surfaces such as stainless refrigeration holdover plates with my IR gun. That's a good choice with any polished surface, but like Everett said, see how far you can throw that chrome housing.

Running hot..assuming radiator, hoses thermostat and pump are good
1/ under advanced or very over advanced at highway rpms
2/leans out at highway rpms
3/Fan not positioned in shroud correct...dump flex fan use the stock
4/cracked head/blown head gasket...HC check on radiator

The trans cooler will make no difference...a 3/16 hole in thermostat may, bottom hose, just give it a squeeze if soft replace, radiator cap replace with 15lb,

Steptoe has some good advice. Definitely check timing, hoses, thermostat, cap and whether the system can hold pressure.

Getting the temp drop from the inlet to the outlet will tell a lot.

Radiator shroud over the Spal fan could be another option, draw more air across the entire radiator. High flow Thermostat like a Robert Shaw (or drill your own holes) might help.

Oh and variation with the sensor...I was messing with mine today, a shiney surface doesnt seem to make stuff all difference, but when I turn the meter over, on the back , under the worn label it says each reading must be done at the same distance...the reason according to the manual...well what is left of the manual...the intensity of the beam varies as to inverse square area of the distance...or something similar.

OH and finding a dead or miss fire on cast iron heads with it is a waste of time...knew a plug was going so time to replace the set...so tried to find which one...according to the temps was ether the pass rear or drivers front middle...WRONG turned out to be drivers middle rear.

Thank you guys for the input. Been very busy and haven't been able to work on my car. Sunday will be the day. I'll check the total timing, hose and carb. Hoping I find the problem, can't be much, the car runs like a "Stripped As. Ape",

Mounted the new gauges in today, look great. Checked the hoses and all OK. Used Everett's procedure for getting the total timing, and here are the findings.
Mechanical Advance Vacuum Line Hooked
Idle 12 27
1000 rpm 12 27
1500 rpm 13 27
2000 rpm 13 26
2500 rpm 24 34
3000 rpm 24 36
3500 rpm 24 36
4000 rpm 30
These are taken with my wife managing the throttle and watching the tach. If it looks wrong I have another person to share the blame.
We took a drive to log the cruise rpms. Here's what I got.
2650 rpm = 55 mph
2900 rpm = 60 mph
3300 rpm = 65 mph
3850 rpm = 70 mph
The MSD distributor with the supplied springs and stop, says I will get a maximum of 21 deg mechanical advance at 4000 rpm. Didn't get that but somewhat close. Guessing that with the timing of 36 at cruise speed, I'm OK?

Didn't come across as typed....
First number is the mechanical number, second number is with vacuum advance.
Idle 12 27
1000 rpm 12 27
1500 rpm 13 27
2000 rpm 13 26
2500 rpm 24 34
3000 rpm 24 36
3500 rpm 24 36
4000 rpm 30

So you are useing man vac to the dizy. It does look like you could bring some mech adv in to the picture you have none untill 2500 rpm. It will run cooler if you ad some. I would say it would be worth a quick sniff of your exhust at both rpms to see where you are at too.

Actuallly, at cruise, you have mech adv plus vac adv plus initial.
So, at 60 mph, mech, includes initial of 12°, will always be there = 24°
vacuum adv = 12° At cruise, you have 36° total.

You need more timing at cruise, say try lighter springs to get mech up to 32°-36°, then add in vac of 12° coming up with a total of 48°. When you go to WOT, vacuum falls off the earth, back to mechanical timing.

Thanks again for the advice! Never messed with advance curves, how do you guy's get to know all this stuff? Interesting..
Well, I can replace the two silver springs with blue springs, and get the timing to come in about 300 rpm earlier, and get about 6 deg more timing throughout the scale proportionally.
Also thinking I should change out the stop bushing. Currently stops at 21 deg and would reach that at 3000 rpm with the new springs installed. Maybe at least go with the 25 deg bushing.

Thanks again for the advice! Never messed with advance curves, how do you guy's get to know all this stuff? Interesting..
Im a bit differnt to most here
1/ I have worked with LPG for yrs, which has a very different curve
2/Also work with vintage, post and pre ww2 working in very diff CR and fuels and engines running on modern fuels


u have about 12 to 14 deg of VA this is stamped on the stem behind the vac unit
3000 rpm 24 36
3300 rpm = 65 mph
going from that u need about 34/36 deg cent at open road cruise rpms plus about 10 degs of vac to take upto mid 40s.

u have only about 16 degs in the dizzy cent (allowing for 'stretch') ...and should have about 22 to 24 degs
I describe in older posts how to file a loittle off the tail of the counterweights to get more advance in GM pionts and hei dizzys

And as Everett says yo nee lighter springs, or 1 spring...to get the cent advance to start to come off closer to the 1000 rpm marks

I have and idle of 500 rpms, the weights come off at 650 rpms...but I using a diff fuel...

Installed the new springs and stop bushing today. Car ran good, maybe a little more power. At WOT I had a slight ping. Thinking I might reduce initial timing from 12 back to 10. Ran the car pretty hard and the temp stayed around 186-188 max temp. Ambient temp at 68, if all remains the same on a 100 deg day. I'll be a happy guy. Thank you guys for all the help.

Only other check will be the HC test on radiator and exhaust. Will have the meter tomorrow.

Thinking I might reduce initial timing from 12 back to 10.
your approach how you think is wrong...

What is at idle (simplistity) means squat..that is what happens when sitting in the driveway
What is important is when the car is moving....

So disconect the VA...take the rpms up till the timing doesnt move and adjust the dizzy timing THEN

Check for ping...is it 1/2 way up in the rev range...light/heavy throttle at a given rpms?
If so due to the high intial and the light springs it would be swinging out too fast on the way up...then when aboiut 36 degs the curve comes back into line

OR with too much VA degs or the vaccuum range it works in at part throttle it is still giveing u too much advance and causes ping ...detonation...death rattle
A general rule of thumb is 3 degs below the rpms/advance point where it is no longer audiable is getting safe...death rattle doesnt need to be audable.

Thinking I might reduce initial timing from 12 back to 10.
your approach how you think is wrong...

What is at idle (simplistity) means squat..that is what happens when sitting in the driveway
What is important is when the car is moving....

So disconect the VA...take the rpms up till the timing doesnt move and adjust the dizzy timing THEN

Check for ping...is it 1/2 way up in the rev range...light/heavy throttle at a given rpms?
If so due to the high intial and the light springs it would be swinging out too fast on the way up...then when aboiut 36 degs the curve comes back into line

OR with too much VA degs or the vaccuum range it works in at part throttle it is still giveing u too much advance and causes ping ...detonation...death rattle
A general rule of thumb is 3 degs below the rpms/advance point where it is no longer audiable is getting safe...death rattle doesnt need to be audable.