Thread: Smokey 4.6 - but why?

Hello there,

A customer dropped in to pick up some bits and pieces and mentioned he has a minor dilemna with one of his vehicles. A P38 4.6 Gems that consistently blows smoke (burning oil) under mid to heavy acceleration.

He hasn't pressure tested or taken anything apart yet however the plug on cylinder 1 is always oily black when taken out for replacement/inspection. No other symptoms like oil in water or water in oil... The customer is thinking he will end up taking the head and sump off pushing cyclinder 1 up and out (didnt think it was that easy?) and replacing the rings on this one trouble piston, or perhaps dropping a good second hand motor in.

Experience with my P38 had me mention the possibility of a dropped liner or perhaps a gasket leak allowing entry of too much oil (but I honestly dont know the paths of oil that could get through without effecting water jacket etc.) as possible problems.

Are there any other simple issues like blocked breather hoses or anything simple he could check before jumping into strip down, or engine change over, work? Any idea's or thoughts much appreciated.

HooRoo, Dave.

The valve stem seals on those things aren't always very tight on the guides, a single missing or damaged inlet valve stem seal can cause significant oil fouling. A compression test first, low means likely a broken ring, high means a thick carbon deposit from a valve stem seal. They can be changed in the vehicle, use compressed air to hold the valve shut and fabricate a suitable lever to remove the spring. Stripping the heads, cleaning the valves and replacing the seals is useful too.