High compression head vs cooling
 

Does using a high compression head create more heat for the cooling system to remove?

I know the heat of compression will be higher.

Re: High compression head vs cooling
 

More heat in the engine but the cooling system does run cooler fron what I have read.

Re: High compression head vs cooling
 

I thought the whole idea was that higher compression makes the combustion more efficient, transforming more energy into power and less into waste heat. So it would create less heat (unless your snazzy new HC head causes you to drive the car faster/longer).

Re: High compression head vs cooling
 

In my experience, the engines run cooler due to more efficient power stroke combustion.

Re: High compression head vs cooling
 

Combustion efficiency is only one aspect of heat generation. It is also affected by the amount of power that is pulled by the engine or how long it sets at idle. Cooling systems will draw the heat away if they are efficient but setting at idle has less air flow than running down the road. If you consistently pull heavier loads or try to get higher speeds than normal then more heat will be generated. With more power there is always more heat under load. Normal driving will have less affect and the difference may be negligible.

Re: High compression head vs cooling
 

When I installed my 6.1 head I had overheat problems at long highway speeds, as before I did not have a problem. I had the radiator cleaned out and flow tested and the shop said it was good. I reinstalled it and I had the same issues.

I installed a Bergs radiator and that solved the problems. Today I can run in 95 degree temps at 55 mph all day long.

Re: High compression head vs cooling
 

My experience mirrors Old31's. The Berg's a terrific radiator. My truck runs so cool I can't really make an observation for the 6.1 head other than it feels like 60hp, not 40. I suppose a light truck has something to do with that. I'm elated with my truck now.

Re: High compression head vs cooling
 

I have a 5.5 head and a 160 degree thermostat with a 50/50 blend of antifreeze. On a hot summer day up a long steep hill on NY's Bear Mountain (2.0 miles+) at 45 MPH the temp went to 170; on the downhill side it dropped to 150. Otherwise it runs at a steady 160. My guess is that if you develop a heating problem that the cause is probably not the head but something such as a blown head gasket with the loss of coolant, or simply a deficient radiator or water pump, or more. Gary

Re: High compression head vs cooling
 

I agree with Gary.

I am also running 50/50 mix but with a 180 tstat.

Re: High compression head vs cooling
 

6:1 Snyders head, 160 thermostat, 50/50 mix. Runs cooler than it did with stock set-up. Chap

Re: High compression head vs cooling
 

As a sort of other question about high compression heads, I have been considering one, but was told that it is sometimes difficult to get the engine to idle properly with a high compression head. Have any of you experienced that problem?

Re: High compression head vs cooling
 

Alaska I have not had any idle problems since I installed the 6.1.

One thing I have noticed since I did my engine work (larger intake valves, touring cam, model b carb, bored intake, bored cylinders, v8 clutch, lightened flywheel) is that I have lost the famous model a chug chug chug at idle. I do miss that sound. The car sounds more like a modern car.

But the gain is well worth the idle sounds of chug chug chug.

Re: High compression head vs cooling
 

I'm still running 5.9 compression heads on some of my model A's and they run cooler than original .

Re: High compression head vs cooling
 

I can't give any credibility to that. I think its non-sense. Just take the time to make carb adjustments, you should make with any equipment change.

Re: High compression head vs cooling
 

Our motor has a 7:1 head and considerably lightened flywheel plus dual Strombergs and the motor can idle as smoothly and slowly as a standard Model A.

Re: High compression head vs cooling
 

Besides the 5.9 head , I run the super street Winfield 3/4 race cam , lighter model B flywheel , dual updraft model B carburetors and a few other minor mods . My model A idles smoothly and has the normal model A cackle at idle with the spark retarded . My car may not idle exactly as slow as a completely stock engine but it will idle purdy slow

Re: High compression head vs cooling
 

Depends if your head is alloy or iron.

"Alloy is for boiling water.
Iron is for power."

It was told to me that the alloy heads conduct the heat into the water faster, which is true. Hence robbing power & creating heat in the cooling system.

Re: High compression head vs cooling
 

My heads are all cast iron . I prefer cast iron for durability , A lot of people have been running the Thomas finned aluminum heads for years , the aluminum heads must be doing some good or people wouldn't continue using them . Hot rods with flathead V8s have been using aluminum heads forever . As expensive as higher compression heads are , I want mine to last as long as possible . I've never had a problem with cast iron .

Re: High compression head vs cooling
 

Purdy and Wen, like me, have you lost the Model A chug chug chug at slow idle, or do you still have it.

Re: High compression head vs cooling
 

Mine still has the model A cackle or chick ah lunk as I call it at idle. They might not idle exactly as slowly as original , but they idle pretty slow with the spark retarded .