Quote:
Originally Posted by gibbo69olds
but if the balancer is crud I am just setting it incorrectly. Wouldn't it make sense to test the balancer first?
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Gibbo69olds,
My first post here and thought this would be a good thread to chime in on.
IMO you have a lot of variables, lots of different things you have tried and possibly multiple causes. Believe me I have been there and I feel your pain. I think you need to go through all the potential causes one at a time and try to break them down as contributors and/or causes.
I think you should address the sitting in the driveway overheating first. Things are easy to test and the engine is under no load so the cooling demand is really next to nothing. I'll ask this question - what are ALL the potential causes of overheating just sitting in the driveway under no load? I'll take a stab and suggest some tests.
1) Air flow
Setup one or two external fans that blow into the radiator and see if this improves things. Take a garden hose and spray the radiator with water. If no change in overheating is observed then your flown may be too low.
2) Coolant flow
Get a IR surface temperature gage (Radio Shack or Harbour Freight) and measure the upper and lower radiator hoses. If the supply hose to engine is significantly colder than the return then the coolant is staying in the radiator too long. I'll measure mine tonight and report back what the temps are for comparison.
3) Head gasket
Run engine with the radiator cap removed and smell the radiator fluid. If it has an exhaust smell then there is exhaust gas entering the cooling system. Check for air bubbles as well.
4) Cracked block
Same as #3
5) Timing - see below
6) Carburetor - I am going to go out on a limb - I would be very surprised if a carburetor could cause overheating at idle. The engine load is almost nothing and I would expect the cooling system to have plenty of reserve capacity to overcome any gross lean (or rich) condition - plus his plugs didn't look bad.
7) Thermostat - I think you said you have run a 160. Have you ever run without a thermostat. Might be worthwhile as the flow should be greater as well.
I would say yes you need to determine where TDC is on the HB. If the HB has slipped then you need to re-mark it. If the HB is moving around this might be like hitting a moving target though - I am not familiar with how these things slip but it sounds like they remain stable after they slip?? As a starting point set the initial timing to 10-12 BTDC with the vacuum advance disconnected and hose plugged. The engine should idle all day long at 10 BTDC. I would also check you mechanical advance by revving the engine to 3000 and checking the timing (you will need an adjustable timing light - not sure if this is the type you bought). With the initial timing set to 10 the total (mechanical+initial) should be about 25-30 BTDC at 3000rpm which means the mechanical is contributing about 15-20. Now for test purposes the vacuum advance is not really necessary so I would leave it disconnected and plugged. This will eliminate one other "timing" variable. I have been fighting a pinging problem and have been playing with different advance springs (HEI distributor) so I have been running without the vacuum advance for most of the summer. No problems other than slightly less cruise throttle response and probably less fuel mileage.
To answer one of your previous questions the vacuum advance can be connected to either manifold vacuum or ported vacuum. Manifold vacuum will give full advance at idle then will drop off and come back up as the engine is revved. The ported vacuum will be zero at idle then will gradually increase as the engine is revved. I don't think one is significantly better than the other although I tend to prefer ported FWIW.
Anyway, give theses things some thought and report back any findings.
1970 Cutlass Convertible, 455ci, TH400