Well Tony,
it wasn´t the diode after all. Somehow after wiring the diode between terminal marked I (the others are A,S and F) on the regulator and the read light which is allways on when the ignition key is on (remeber, it's a Contemporary, and has this red light which is always on with the ignition and a blue one for the lights) the dieseling did not happen after three trials. Next day it was all the old story again.
I noticed that the valve covers and heads would get very very hot in just 5 minutes with the engine just idling.
A very hot compression chamber can cause dieseling.
Since the dieseling did not happen before the last rebuild, which only included a sharper cam (282S comp solid cam), I recalled what else I did change. One thing was the addition of an
oil restrictor in the oiling hole to the rocker shafts. The restrictor may improve oiling to the crankshaft, but that is only an issue with a regular pumps. A high volume pump will probably not need a restrictor to supply suficient
oil to the crankshaft. What the restrictor does is to allow less
oil to the valvetrain, and so prevents it from getting enough cooling through the oil.
I removed the restrictors and the engine does not get as hot as before, even after 10 minutes running I can still touch the valve covers with my bare hands.
I will keep the restictors removed for now, since the oil pressure did now decrease.
But, dieseling still happens.
I am now having a close look at my carburetor, because the throtle blades do not shut completely, and I always see gasoline around the accel.pump injector and on the blades in the primary bodies when I shut the engine off.
I think this is not normal and believe that is has something to do with the dieseling.
Does this happen with your carburetor? Mine is a 850CFM all mechanical 4 barrel Holley. I would very much like to know if that wet aspect of the carb is happening to anybody else.
I'll keep a post on this as soon as I make progress on this nasty dieseling.
Any suggestions welcome
Stefan Pietzsch
Threaded Mode
