A friend of mine has asked I submit the following overheating problem. It has been a VERY frustrating year and hope you all can help. The message is lengthy but want to provide all the details in chronological order for your analysis. Thank you in advance for your help!!! r
Four years ago I purchased a "strap on" race car, namely a 1967 Cougar set up as a TransAm car. My car has had virtually the same set up for several years and served me well, without significant problems, through 3 racing seasons or about 2200 miles.
In the winter of 2002-03, I redid the motor since it seemed time and for no other reason. Block, heads, crank retained -- New pistons, rods, valves, etc. Original engine produced 300 rwhp. Rebuilt engine was bored 40 over and stroke was lengthened, do not know rwhp of current set up but undoubtedly more.
On the track it did OK in Feb and Mar when the ambient temps were in the 40's and 50's up at Willow Springs, but it must be realized that no true race temps were ever achieved.
Conditions changed in April and we experienced very erratic swings in the water temp. 220 - 260+ and back in space of 1 or 2 sec. when racing hot and heavy. We asked you folks for help and it was your conclusion that the coolant level was down and there was "cavitation."
I accepted that, brought coolant level up (it was down) and raced again in Jun at Willow Springs. The same wide/rapid swings in coolant temperature were noted. In addition we found coolant level falling by about 1 gal each 15-20 min race. A small amount of white foam was found in the oil which was considered, by most, to be insignificant. At the shop, a small crack in the head gasket at # 8 was found and thought to be due to inadequate / improper torquing of head bolts, some were "loose."
With "problems" "fixed," returned to track. This time we were on the long course at Fontana on a very hot day, track ambient approx. 110. I was able to make only 3 or 4 laps before the same wide/rapid swings in coolant temp would recur. Again I found coolant level down about 1 gal and slight foam in oil. Brought coolant level up and tried it once more with the same result. Back home a crack in the block was found which was said to be "only evident at race temps."
With block replaced, same inerds, returned to track convinced we now had the problem/s solved. You guessed it, NOT! Exactly the same temps were noted again; that is to say, coolant over 250 and oil over 260 whenever engine exceeded 4500 rpm and believe me you are not racing or having fun at that speed. This time it was felt that my Griffin radiator was plugged up with "crap" from the Ford small block/s.
Reverse flushed the radiator and put car on chassis dyno with similar results.
As you may be aware, this is not a radiator which can be rodded out with ease, so it was replaced and in addition a Gano filter was installed in the top hose. Again the car was placed upon chassis dyno and run up to 6000 - 6500 rpm with the same overheating of coolant and water.
Needless to say, I am very frustrated and would like any help or suggestions that you might have.