Thread: 327 Running Hot

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Just had it rebuilt less than 50 miles ago, shop talked me into purchasing a radiator, water pump, fan clutch, thermostat, fan shroud, electric fan, and it is still running hot. Now they are telling me that the engine is new so it is still tight and this is why I'm still running hot.

When does it get hot? Sitting still? On the highway at speed?
Make sure the fan if blowing back through the radiator and not blowing from the engine side. The fan will run both directions depending on how's it's wired.

If your using an electric fan how are you using a fan clutch?

As far as the engine being new and tight: Thats BS. If thats the case they didn't build it right. A newly rebuilt engine should have all the clearances right when they rebuild it.

Originally posted by Ron Golden
When does it get hot? Sitting still? On the highway at speed?
Make sure the fan if blowing back through the radiator and not blowing from the engine side. The fan will run both directions depending on how's it's wired.

If your using an electric fan how are you using a fan clutch?

As far as the engine being new and tight: Thats BS. If thats the case they didn't build it right. A newly rebuilt engine should have all the clearances right when they rebuild it.

It overheats sitting still and the temp may stay at about 210-220 degrees while driving. The electric fan is mounted to the front of the radiator and the fan on the motor is still working. Yes, the electric fan does it does blow through the radiator.

Not sure if this has anything to do with it but the mechanic says it needs a vacuum advance.

Hey Oli,
Throw a vac advance unit in the distrib. or advance the timming to about 16 * initial and plug or remove vac hose. The bad vac unit is causing a vac leak so running leaner than ideal and engine wants more timing anyway.
I remove vac advance units from all my distrib. to get more reliable timing adjustments ( vac unit allows variations from slop or slack in the plate). Then I add all the initial the engine will take and fill in with mechanical until total is about 38 to 40 max in by 2500 rpm.
Vac Advance unit helps milage and emissions but little more.

A vacuum advance will help cool an engine, but only slightly in most cases. During high manifold vacuum conditions (typically at cruise and very low throttle opening) the fuel density inside the cylinder is very low and the fuel charge must be ignited sooner. The vacuum advance unit increases the timing several degrees and the spark plug is fired sooner in the combustion cycle.

With the vacuum advance disconnected, set your initial timing around 10-12 degrees before top dead center on # 1 cylinder. Watch the timing marks with a timing light as you raise the RPM. The timing should increase to about 35-40 degrees at 3000 RPM then stop advanceing.

Have you checked your thermostat to verify that it opens at the right temperature? Put it in a pan of water with your wife's candy thermometer and bring the water temp up to about 180 degrees. Watch closely and the thermostat should open around that temp.
Make sure the thermostat isn't installed backwards.

Put a BIG fan in front of the car and have it blow directly into the radiator. Let the engine idle and see if it stays cool. If the engine stays cool at idle a better fan system will solve that problem.

Another thought...get the engine warm and check the water temp with your wife's candy thermometer. Remove the radiator cap and stick the thermometer in. Don't let her see you do it. Wife's don't have the same priorities we do.

If the above doesn't solve the problems send me an e-mail and I'll send my phone number so you can call me and we can discuss it.

Ron

Yes.