I am at the point in disassembly where I decide whether or not to take the block apart. Head
is off, valves are all pulled.
The main reason I did this was because I was getting a TON of smoke at operating temperature just POURING out of the oil
fill cap (and my temporary fix involved getting a rubber stopper and about 15' of 1" hose, and just ran it out the port side head
porthole while running the engine
, so all the smoke wouldn't fill up the cabin). It was one of two things: cylinder blowby or valve guide blowby.
The first thing I did was a compression
test, at operating temperature, even before the engine
came out of the boat.
Results were basically 90-90-90-90 for each cylinder dry. (that is good - I think)
then I did a wet compression
test and got approximately 97-110 for them.
But the smoke kept coming. Coming and coming and coming. I got fed up with it and decided that I was going to start taking the thing apart to try and see if there was any obvious maladies with the engine (scratched cylinders or something). So I took the head off and looked at each cylinder wall - they looked pretty darn good except for the following:
The red areas are barely visible in just the right angle of light and not even feelable unless you REALLY focus and use your fingernail to scratch it... light vertical scratches.
I am also able to wiggle the piston around in the cylinder at TDC, so I know for a fact that the rings are not frozen.
These things are telling me that maybe I was wrong all along? maybe its NOT the cylinders that are the problem?? Could it be the valve guides? and if so - then how hard is it to size/install new ones? What about lapping the valves and the seats?
I guess my main question is: how do I know for CERTAIN that the blowby is occurring at the valve guides OR the cylinders? I've done basically everything test-wise to determine, and this thing is just sitting on my bench, mocking me - telling me "yesssss, take me completely apart and spend 3 thousand dollars fixing meeeeee"
(I'm not rich by the way)