In a message dated 96-12-21 17:50:55 EST, wassallj@philly.infi.net (Jay
Wassall) writes:
<< previous owner said he thought it had a burnt valve. Could that be
causing all the smoke from the filler cap? >>
I sure don't see how, unless you also have real bad valve guides. First you
would have to have worn valve guides to let oil into the cylinders to burn.
Then the smoke would have to come out thru the burnt valve, back through the
valve guides, rather than going out the exhaust or intake manifold, depending
on which valve is burnt. It seems more likely to me that the rocker shaft
and rockers have insufficient oil flow and are getting hot, or you have worn
rings,(or broken rings in one or more cylinders) and there is a lot of
blow-by, causing smoke in the crank-case, which filters up out of the oil
filler cap when you stop. Do you also get some out of the breather tube on
the driver's side of the engine? If so, it would make the worn rings
diagnosis more likely. In any case, what you need to do is test the
compression in each cylinder. They should be around 135+, and within 5 or 10
pounds of eachother. If you have a low one, you can test to see if it is a
burnt valve by squirting a little oil into the cylinder to coat the rings,
and see if the compression improves. If not, it is a valve problem. If so,
it is a ring problem. (A better test would be a leak-down test.) Since you
have such good oil pressure, I wouldn't expect the engine to be worn enough
to have worn-out rings, so you could have broken rings or a scored cylinder
in one of the cylinders. If none of the fore-going helps, can you quick get
the valve cover off when it is smoking, to see where the smoke is coming
from? Could it be steam from a crack in the head, or a loose water plug?
(There is one, I believe from memory, on top of the head between the #2 and
#3 cylinders.) Or if you have a lot of gunk built up under your valve cover,
clean it good and see if that helps. Finally, it might be possible that the
oil return lines from the top of the head to the crankcase are clogged, and a
lot of hot oil sits on top of the head after you run it hard, and smokes a
little. If this is the case you might see a lot of smoke out the tail pipe
when you run at high speeds for an extended time. Well, I guess I've beat
this one to death, so I'll sign off now. Be sure to keep the list posted on
developments.
Paul
|