New motor, new water pump, new thermostat, new radiator cap (16 psi), new hoses, new heater control valve, new antifreeze, still runs hot?? Any suggestions?
Your radiator is the number 1 suspect. If it is old, it is likely corroded internally slowing the water flow. An ignition timing issue is next. Fan shroud in place and correct? Does it do this when you are driving down the road or just when it idles?
By hot what do you mean.? Do you have a temperature guage in it that is marked in Degrees ? Does it boil over ? Is it when you drive on the highway or in stop and go traffic ?? There is not enough information here except a lot of new parts to make a GUESS .
Besides the radiator, a newly rebuilt motor with fresh rings will run a bit warmer than a well broken in motor. My experience on a fresh rebuild is about 500-600 miles until it starts to cool down at operating temp by about 10 degrees .. of course, that's with a NEW radiator in place. mike <script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/ec365c77/background/helpers/prefilterHelper.js"></script><script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/ec365c77/background/helpers/prefilterHelper.js"></script>
No answer to Jim's question, so I will ask it again: Is the fan shroud still behind the radiator? Hey Cujo, since you are from Atlanta and own a model year 1971 Riviera: Is this your car?
As has been mentioned I suspect a combination of a bad fan clutch and not enough initial timing. Have you checked timing and what is it set at? And, are you running manifold vacuum into your vacuum advance canister (or, ported vacuum?)
New fan clutch. Running this cam: Comp Cams # 96-203-4. Degreed at 106.0 intake center line (as recommended). Current timing is 4 degrees at 600 without advance. Running manifold vacuum to the advance.
What is the overbore on the new engine? What size and type (aluminum or brass/copper) is the radiator? What thermostat are you running?
30 over, radiator appears to be copper. Thermostat is 180; reduced it from the 190 trying to stop it.
So, the initial timing is set at 4 deg BTDC. What is the idle timing when you hook up the vacuum advance canister?
Overheat at idle is a water flow problem. Check radiator and thermostat and water pump. Overheat at speed is an airflow problem. Check fan, clutch and shroud. Assuming timing is correct.
Don't you mean just the opposite? My experience is that overheating at speed is a poorly circulating radiator or water pump. I recently resolved a hot idling 455 by replacing the clutch fan and increasing timing.
Since you have a new radiator and a new radiator, check to see if the sealant used to build the engine has migrated to the radiator and stopped the water circulation. I have seen this happen. Lower the water level and look into the filler hole with a light.
