I just got my 502 MPI rebuilt. The builder ended up going to bronze sleeves for the valve guides. The motor only has about 10 hrs, 8 break in on his dyno, 2 on the water. I've noticed that after running around, shutting down, then starting back up, i get a quick puff of oil smoke. Leads me to believe oil is going down the valve stems and sitting on the piston upon restart. I'm running straight weight 30W break in oil, and will be putting the 20-50 in shortly. Anything to be concerned with? Builder told me to run it, but don't know if he's blowing me off or not?

It should be completely broke in after 30 mins. I would see if it continues after you switch oil.

i was just a little concerned that it shouldn't be doing that at all with only 10 hrs. But, maybe i shouldn't worry about it.

i was told the same thing on my builds. Now mine is doing it ALL THE TIME AT IDLE looks like i my be pulling mine out now

Sorry to hear it. Mine has the bronze valve guides, so i don't know if that changes anything. Not sure if valve seals are still used or not?

You getting it covered under a warranty?

Cloud,
The bronze "sleeves" are fine if installed properly. It almost sounds like he did not use a good valve stem seal. Most builders that I know are using a metal cased viton rubber type seal. It could also be an intake manifold leaking, but that should cause it to smoke all the time and use some oil. Have you noticed any smoke behind you or an unusual amount of oil usage ?

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

Talked to the builder tonight. He said a quick puff will be normal for the type of seals he used. He did not use the normal "umbrella" type.

on my blower engines I do not use exaust seal at all since 1978 slightest puff on refire never had a problem but of coarse they are my boats

Mine developed the puff at start up, then all the time at idle and nuetral revs. Turned out water had been dripping into head from a leak at the exhaust riser gasket. Damaged valve and guide. Never found full extent of damage becuase I sold the boat while under repair.