Al -
Some random diagnostic thoughts based on what you've said...
You're running the crankcase ventilation to the SUs, I'm assuming via
the air cleaner. What does the inside of the air cleaner look like? Is
it an oily mess or just a little discoloration? If it's an oily mess,
your timing cover vent is sucking up oil rather than just vapors, and
you're aspirating oil into the carbs. Perhaps you're drawing air in
past the vented cap, which is picking up oil spray from the rockers et
al, and drawing a constant mist of oil into your carbs. I'd be tempted
to try a non-vented cap just as an experiment. Heck, it's cheap enough.
It's possible that your compression rings are fine (hence the good
compression), but your oil-control rings are shot (hence the oil
burning). Unless you're burning a lot of oil, I'd be tempted to not
worry about it.
While I'm thinking about it, are you losing measurable amounts of oil?
A quart in how many miles? If you're not even losing a quart between
oil changes, I think you're worrying too much.
What do the plugs look like? Black and gooey or black and fluffy? If
it's black and fluffy, you're running way rich. Black and gooey is
oil. Not black at all? See previous paragraph.
Hope this helps...
Chris Kotting
ckotting@iwaynet.net
"Tocci, Al" wrote:
>
> O.K. list, I'm feeling some frustration by the amount of oil my car seems to
> be burning for possible reasons other than tired rings or valves. Here are
> the facts:
>
> - 1275 no-smog equip motor running 20W-50 oil
> - freshly rebuilt head by very reputable shop - new guides,
> seals, et al
> - compression readings of 183 - 190 lbs each cyl w/ all plugs
> out, throttle wide open, and no additional oil in the cylinders
> - crankcase is vented thru timing chain cover (dah) into the
> S.U.s, NOT into the intake manifold thru a PCV valve.
> - aftermarket valve cover with VENTED cap
> - exhaust seems to smoke most in the midrange (around 3000
> rpms) vs. start-up or under heaviest acceleration. I'm sure it's pushing
> more oil at 3000 rpms than it is at 4500 for example.
> - oil pressure consistent with what other folks report
>
> So, any ideas? Thanks much...
>
> Al Tocci
> Doylestown, PA
> '66 Sprite
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