Paulsv@aol.com wrote:
>
> 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
The exhaust does not smoke at all, I suspect it would if I had a broken
ring. I will check the oil passages. Thanks for the quick and thorough
response!
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