Quick question for all you folks up on your engine troubleshooting.
Background:
'64 Spitfire Mk I assembled in Spa, Belgium.
Engine # FC74172HE. I know the engine is a transplant, possibly from a
Herald (?)
Rebuilt the engine about six years ago. Cylinders were round (not ovaled)
so I had the ridge cut down and the bores honed. Pistons were within
tolerance so I just installed new rings. Additionally, I installed new
bearings (rods, mains, and cam), thrust bearings, valves, valve guides, oil
pump, gaskets, etc. Engine then sat up about four years while I did the
body work, went over seas for a year, etc. I pickled it before leaving
(oiled the cylinders and intake, sealed the carbs, replaced the engine oil.)
Finished getting it road worthy about two years ago.
It's always leaked a little oil (what spitfire doesn't???) but starting
about 6 months ago, it began to get progressively worse. I'm up to about a
quart a week now and I'm only going about 100 miles. I'm pretty sure it's
blowing it out of the crank case vent, an inverted J-shaped tube behind the
exhaust manifold. To verify, I plugged it up and the engine proceeded to
spew oil from the dipstick tube.
I checked engine compression this evening. Readings looked OK, I think.
1-2-3-4 were 125-115-130-120. I added a little oil to each cylinder and the
compression did come up closer to 150 across the board (really high?).
Also, I checked the cylinders w/ a bore scope and didn't see any scoring on
the far wall.
The engine seems to run strong ever since it was rebuilt. I run it a tad
rich (a little dry black soot on the plugs) so that it doesn't overheat.
So the question I'm posing is this: What's causing my excessive crankcase
pressure? I think it's blow-by, but the compression readings look too good.
I can't imagine a blown head gasket causing this. Valves seem to be fine.
Could this be from running too rich i.e. washing the cylinder walls?
Any suggestions would be appreciated.
Chris
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