Hi Guys,

Need some of your sage advice to help me solve an overheating problem. I have a 496 stroker with a Hughes 237* cam and 10:1 CR, eddie heads and headers in my 4200lb C-body. I was running a 24oo stall converter and 3:23 gears.

All was well until I lost a cam lobe to my laziness of oil maintenance. Anyway, rebuilt the motor with a slightly smaller cam (233*) but added a 3200 stall converter and 3:55 gears. The car seriously overheated to the point of pegging the needle and boiling over. This happened within 3 hours on the new motor. I also broke a lifter and had to pull the motor for a redo cleanup, new lifters, etc. Put it back in the car and ran it. I also had my radiator rodded out and installed a new 180* thermostat. Now the car idles at about 190* and runs under mild load at about 195. When I get on it the temp goes to about 200-205*.

My thoughts: The engine did not overheat with the 2400 stall converter.
The radiator is now in better condition to cool the motor.
I have a large factory trans cooler.
Using a factory shroud and clutch fan.

I think the problem is the 3200 stall converter in the 4200 lb car does not work for me and i should go back to the 2400 stall converter.

What are your thoughts?

Well you found out that the stat can not control temps above the stat rating. If the temps don't go above the 205 or so you won't hurt anything not will the 190/195 driving temps.

205 is not a problem. Modern cars run that hot normally. You can run 210 and still be good. When you had the 2400 stall, it was tighter and didn't "slip" the transmission. This is why your temps are higher now. You can try adding "water wetter" or some of the other cooling system additives. These can drop up to 10* off your temp. BTW, do you have an external trans cooler? If not, you may want to add 1. It'll help.

New higher stall converter slips more. More slip = more heat. That heat goes into your rad via the stock trans cooler. Plus you can be running the engine a little higher with the extra slip. 205 is nothing to worry about. Put on a large external trans cooler before the rad trans cooler if you want to knock trans temps down.

Did you replace the old stat with a new high flow thermostat like the mr. gasket, milodon type?
These thermostat open like you havent any thermostat at all and move the cooling water much faster around the system. That may cause that the radiator not cool it down enough.

Thoughts, 205 isn't a problem. That's still below boiling of water, and well below boiling of coolant. NASCAR motors run 240 degrees all day long.

I don't know if you have or don't have an auxilary transmission cooler added on to your system, but if you don't put one on.

All converters are designed to have slippage in them until they go past their rated stall speed. When converters slip, they make heat, and high stalls can generate a lot of heat.

In my opinion (based on a lot of years in the automatic transmission business), the best cooler available is made by a company called Long Manufacturing. Their coolers are designed like a true radiator(unlike old school tube and fin coolers), and will disipate the most amount of heat. If you can't find it under the Long name, look for it under the B & M name. Don't be shy about the size, and make sure you mount it properly (don't strap it through your rad though). Use it in series with the transmission cooler in the rad, if the one in the rad is in good shape. If the rad cooler is in bad condition, get their largest model and by-pass the rad cooler. I did this on a 71 Duster I owned years back, and never had any heating problems from either the transmission or engine.

Graham

Thanks for the replies. I replaced the thermostat wiuth a Stant 180* from NAPA. I have the factory trans cooler. This car has a factory towing package with a large 26" X 14" fin and tube trans cooler in line with the radiator cooler. I am going to change the torque converter out tomorrow. i like the response of the 2400 better than the 3200 on the street.

Post back and let us know if that solves your problem or not.

With a big motor and a little cam I bet you don't need that high stall to get to the power anyway.

Swapped out the converters this afternoon and drove the car around, got on it a bit and the engine temp was about 7* cooler with the 2400 TC than with the 3200 TC. No other changes. Nuf said.

Yeah, we dynoed the motor after the build and got 613 lb/ft of torque and 510 HP. The max torque cam in at 3400 rpm and the hp came in at about 5300 rpm. So you are correct, I really don't need a high stall converter for this combination.

Thanks for all your replies.