I recently read the messages on the discussion board addressing timing and the great explinations on the relationship of late timing and the build-up of heat.This helped to clarify some of my questions related to a problem I have with my 1970 454 4 speed original engine non TI Corvette. The engine runs hot if it is idling or operates at lower RPM and light loads. I replaced the TCS system that was removed when I bought the car. I am concerned that either it, the fact that I rebuilt the engine with a higher lift and different duration Chevrolet manufactured cam instead of a new 390 HP cam as originally install at the factory or combination of the two is the cause.
I intend to bypass the TCS vac piping and connect the vac advance directly to the manifold as a test to see if it maybe interfering with advancing the timing under light loads and idle.
I must confess that I listened to advice on installing a different cam prior to doing the proper homework on its effects and potential problems or other modifications that maybe required to sucessfully make the change. The cam is still a hydrualic lifter cam and the Chevrolet recommended valve spings were installed.
I would like to know what effect could be expected on the timing due to this cam change, could it be related to the heat condition at light loads and how would performance be effected.
I must also state that the original Rochester carb is on the engine with original jetting. I have noticed a smell of unbured fuel in the exhaust at idle and when the engine is running hot it tends to loadup. The loadup condition does not happen when originally started or if operate under heavier loads.
All input on my delema is welcome.
I intend to bypass the TCS vac piping and connect the vac advance directly to the manifold as a test to see if it maybe interfering with advancing the timing under light loads and idle.
I must confess that I listened to advice on installing a different cam prior to doing the proper homework on its effects and potential problems or other modifications that maybe required to sucessfully make the change. The cam is still a hydrualic lifter cam and the Chevrolet recommended valve spings were installed.
I would like to know what effect could be expected on the timing due to this cam change, could it be related to the heat condition at light loads and how would performance be effected.
I must also state that the original Rochester carb is on the engine with original jetting. I have noticed a smell of unbured fuel in the exhaust at idle and when the engine is running hot it tends to loadup. The loadup condition does not happen when originally started or if operate under heavier loads.
All input on my delema is welcome.
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