Help with overheating

[Gerard F.]

Re: Check the carb

Sorry Duke, I've always had a 160 on it, and thought that was OE for a original back east 67 base engine car with no AIR. I learn something every day.

Is there any detriment to always running too cool?

Also, it seems to run a little cooler with the C1-4 plus oil, but I don't really have any quantitative analysis.

Jerry Fuccillo
#42179

[Doug Flaten]

Re: Help with overheating

I use the kits to back flush. They have instructions on which heater hose to tie into. Also do not forget to remove the block drains and try to clean out the water jacket of solids. Sometimes they are plugged with crud. Leak stop will often accumulate in the drain valve or in the water jacket.

With regards to the 75% glycol mixture, my engr data says the BP of a 75% mixture is 248 F at 0 psig. At 16 psig that will put you in the 290 degree range for a boiling point. A 50/50 mixture has a BP of 222 F at 0 psig and with the 16 psig cap, the BP is around 258 F. At 200 F, the 75% mixture has specific heat of about 0.75 vs a 50/50 mixture that has .85 btu/lb F. The 75% mixture also has higher viscosity and density. These two factors would either reduce coolant flow a bit or increase the horsepower required achieve the same flow rate. The only positive thing for the heavier mixture is that it will raise the operating temp which will increase the amount of heat that can be rejected through the radiator by increasing the temperature differential. However, this is offset by the reduced amount of heat that the 75% mixture can carry and the reduced flow rates. It is probably better to go with the lighter glycol mixtures. If freezing is not a big concern, some fleet products have corrosion resistant additives that you can use with a reduced glycol concentration which would aid cooling.
Doug

[Duke W.]

Re: Check the carb

The industry went to 180 degree 'stats with the switch to "permanent" (ethylene glycol based) antifreeze in the early sixties; 160 'stats were used with the old alcohol based antifreezes that would boil off at higher temps.

Actually, the AMA specs show a 170 'stat for '63, but later years were 180 and that's what I recommend for all earlier engines. Emission controlled engines beginning with the '66 model year in CA and '68 for the other '49 states usually have 195 'stats.

Engines actually like to run hot (especially aluminum engines). Higher jacket temperature reduces heat transfer to transform more of the fuel's energy into useful work at the crankshaft. Chev. Product Performance has been telling us for over 30 years that HOT cylinder walls mean lower friction, and NASCAR guys don't pull tap until the water hits 230 (I think they just run straight water with an additive like Water Wetter and a 21 psi cap).

Also, low temperature will cause more crankcase condensation.

A 160 'stat will not solve overheating problems. Since it opens earlier it may take a few more minutes for overheating to occur, but that's it. The thermostat only controls the MINIMUM coolant temperature. The max coolant temperature is a function of radiator heat transfer capacity and air flow thrugh the core, and a proper spark ignition map is required to not overload the system's cooling capacity.

Duke

[Gerard F.]

Re: Check the carb

Gary,

Not sure what you are referring to as the "adapter" glued to the intake. Do you have a CI or aluminum intake, and do you have a 3367 Holley or equivalent on it? If you have the stock CI intake, there is a stainless steel baffle which goes against the bottom of the carburetor, the gasket goes against intake. If you have them reversed that might be your leak. Not too sure about the aluminum intake but I don't think they have a baffle, but I still think the gasket goes against the intake. That is, unless you are adapting to different carburetor.

Also that whistle could be in the setting of the secondary butterfly. Maybe it is too far open at idle or slow speed, which would give you a lean condition.

Jerry Fuccillo
#42179