<VV> dieseling/smoking engine

[Michael Kovacs]

 My '69 Fitch has a strange ailment. After getting the engine up to driving temp (CHT about 250-300) upon coming to a stop, the engine decides to violently diesel (2-3 seconds) with a great expulsion of white smoke then it idles normally. Very destructive, not to mention embarrassing.

 The engine is a 140, .060 over, CR is about 9.25:1 with a .032 head gap and octane cut pistons, using 93 octane for safety. It is a very strong running engine and gives no hint of a problem when driving. 

 I am assuming that there is a hot spot somewhere in a cylinder head and this is causing the problem. I know I also have to reduce the jet size back to .052 from .056 as it does run rich.

 While I have the primary carbs off, I'd like to try colder 42 spark plugs instead of the hotter 44s. It is a cheap way of trying to solve the problem.

 Any suggestions would be helpful. That is to say any technical suggestions!!!

 
 MIKE KOVACS