C1 overheat

[Ray Hoctor]

Thanks for the response. I checked the gauge two ways. First, I pulled the sensor and put in heated water of known temp. It appeared to accurate up to 190 degrees. Today, I purchased a mechanical temp. gauge and plugged it into the other side of the manifold (Edlebrock) and compared the two. The orginal gauge is off and reads high above 190 degrees. However, the more is idled, the hotter it got. I shut it off at 220. Now. I need to check the timing and I do not have the shroud installed. These I will do today and report the results. Also, it is a new aluminum radiator.

[John H.]

Re: C1 overheat

Ray -

The shroud will make a WORLD of difference; idle heating is a result of inadequate airflow through the radiator (in addition to retarded idle timing), and without a shroud, you're losing about 60% of the airflow through the core. Make sure the tips of the fan blades are positioned half-in/half-out of the rear edge of the shroud, as originally designed; that's the design condition for maximum fan efficiency. You should have zero heating issues with a new aluminum radiator and the correct shroud/fan relationship. What kind of distributor do you have, and does it have vacuum advance?

[Mike B.]

Re: C1 overheat

Ray,

I had the same problem with my 61 when first purchased. Previous owner used an aftermarket expansion tank only for overflow and blocked off the radiator and water pump. I put in the correct tank and corrected the plumbing and problem solved! I also put in a Mr. Gasket hi-flow thermostat which might have helped (even though I knew the stock thermostat was functional).

There is a product called "Water Wetter" available in auto parts stores for $10. It claims to lower temps by 20 degrees. This is not finding the cause, but it might provide enough of a "fix". It beats pounding your head against the wall!

Good luck.

[Ray Hoctor]

Re: C1 overheat

I just finished retiming the engine. It was retarded about 3 to 4 degrees. I also installed the shroud. So far, this seems to solve the overheating problem! Very dramatic and way too easy. I still need to get the proper heat sensor since mine is not a Delco and it does read high. Thanks very much to all of you for your help. I'll post my next problem on a different thread.