Hi, just got back from a road trip yesterday and was a little surprised with the car's engine temp. Background on engine is basic stock 1972 350, with rebuilt heads. ( I put the larger TA valves in 1972 heads). Converted car to a 4bbl with cast iron intake. Removed A.I.R. system, along with T.C.S. I am pretty sure i installed stock thermostate, 195? backed up with an aluminum radiator. (just the cheap one from Auto Zone 151? ). New hoses, fan clutch and water pump. Still running single exhaust. Anyways, installed autometer mechanical gages. At highway speed, outside temp was approx 70deg, engine temp was 205deg with A/C on and 195deg with A/C off. I thought this was a little high. Did some research on board here and came across a post by Larry that the initial timing for the 72 is wrong a 4degs. My question is, are these temps acceptable? Never had a real gauge on this car before. Should I adjust the initial timing from 4deg? (I did install a new timing chain and gear to replace nylon unit). Finally, I still have to install the grill into the car. With all the work going on, I didn't want to lean in and break it. Thanks, Chris.
That is not "too hot" with A/C and 195 F stat. What temp at idle both with and without A/C? Do you have a shroud, correct fan, is the fan blades 50% in and out of the back opening of the shroud, and if it is a clutch fan, is it working correctly? Is the evaporator clean and fins straight? Does the heater put out heat? Timing is important, you need vacuum advance at idle and cruise, otherwise it will be late on both those events. Cap needs to be 14-16 lbs and system needs to be pressurized to the cap's rating. Hoses need to be rigid. Old hoses, especially bottom if soft, can collapse. Thermostat can be tested in boiling water. should start opening about 5 degrees before rated and fully open 5 degrees after rated (plus or minus 5 degrees since your not in a calibrated setting is fine) Temp gauges and sending units can be off out of the box. (so much cheap garbage nowadays, even brand name stuff can be a crapshoot. You can get a IR thermometer/gun and test the outflow/top of radiator, heads, intake and thermostat housing as well as each exhaust port area on the manifolds to see if there are any hot spots and how close temps are to the gauge reading. Read Larry's power timing thread. (and adjust to that) initial timing in a 50 year old may or may not be relevant, given that the cam, distributor may not be stock, cam dialed in different, distributor recurved etc.
This is average temp . You want it lower try a 185 thermostat or a 160. I would add timing. Todays fuel can use more timing. Follow Larry’s thread on timing as recommended. You can for now just set initial to 8-10 at idle. If you get ping or spark knock back it down a bit.
Will be looking at the beast tonight. Can test vacuum advance. Also, need to make up piece of tape to power time. My cheapo dial back timing light is junk, need to rely on the early 80's unit. New light ordered for Bowling Green pickup. Will change to a cooler thermostat. Update by weeks end.
Why would you expect the engine to run cooler than 195*? The thermostat won't let it. The thermostat sets the MINIMUM temperature for the cooling system. Engine temperature should be within 10* of the thermostat rating, yours is. Your cooling system is working well. Want it to run cooler? Put a lower temperature thermostat in. Stock initial timing for the 1972 350 is 4* BTDC. The stock distributor is part number 1112109. Lets look at the specs for that distributor, 12-16* MAXIMUM mechanical advance. Lets do the math, the total timing at WOT can only be 4+16=20*. That is leaving power on the table. Buick engines make best WOT HP with 30-34*. If you have a different distributor in your engine, then the initial timing book spec goes right out the window.
You are correct Larry. 195deg t-stat should control at that temp. I just thought at highway speed I wouldn't see 200+. I was worried about timing. Going to Napa at lunch to grab a cooler t-stat and will verify the distributor number. Can't leave any HP on the table. lol. Also ordered distributor spring kit from summit for BG pickup. Quick question, is a 160deg t-stat too cold for street use? Or should I get a 180deg unit. Chris.
Why do you want to go cooler? Gas engines run most efficient at higher temps. If it is stable and not puking coolant, you are good!
I always use 180 thermoset and drill a 1/8" hole in the flange to prevent a air bubble. Just put a Fail-Safe thermostat in the kid's Mustang. Fails in open position. Never heard of it before. MotoRad Fail-Safe® Thermostats | MotoRad
160* is too cool, 180* is perfect compromise between efficiency and performance. Retarded timing will make any engine run hotter. Your highway cruise timing should be low 40's for best economy and coolest running. Verify that your VA is working.
That thermostat testing is bogus as the thermostats are sitting at the bottom of the pan. To properly check they should be wired up to NOT touch the bottom of the pan. They need to be suspended. Tom T.
I've got a 195 stat, aluminum 2 row radiator, 7 blade clutch fan, and a flowkooler water pump in my Regal. Stays right at 180-200 no matter what even in boiling summer traffic. Even cooler when I had dual electric 4th Gen camaro fans wired full beans.
