<VV> Advice on Rings (was Help - Oil Out Dipstick Tube)

[tkalp at cox.net]

First, sorry about your bad luck with the new engine.

Second, how to isolate the problem to rings or valves.

Pull the cylinder up on top-dead-center

Pressurize the cylinder, it only takes 10 - 20 lbs.   My screw-in compression gauge has a quick disconnect from the hose to the gauge.  Pop the quick disconnect apart and use the hose end only.  Remove the Schrader valve at the end of the hose that goes into the cylinder.  Screw the hose into the spark plug hole.  Hook up a regulated air supply to the quck connect and listen for air escaping.   If you hear it in the crankcase it is rings (or a holed piston which is highly unlikely in your case) If it is in the intake, check the intake valve . . . . exhaust, exhaust valve.   If a valve is leaking losen the rocker until there is some clearance, if it still leaks it is a valve problem.

Even the best make mistakes once in awhile and I do it all the time . . . .  Check everything, find out what is wrong, fix it then enjoy your Corvair.   Don't panic at a puff of smoke at startup,  most of mine do it once every couple of years, parked at an angle, or just plain onreyness.   Do watch the compression, that is the true indication of your problem.  Good Luck.

tkalp
wichita, ks


---- Jay Pitchford <jay.pitchford at gmail.com> wrote: 
> First a refresher - here's where we entered my little saga last week:
> 
> ************************************************************************
> 
> "My '65 140-4 Corsa just finished it's rebuild today and on the initial
> test drive, the mechanic is getting oil blowing out the dipstick. This
> engine had a complete tear-down, including boiling the block, turning
> the crank, new bearings, pistons, rings, the works. I'm going to have
> him check the PCV, but is there any other suggestions you can pass on
> to me for him to check? The car is an hour away from me, and I'm
> desperate to get it back for the long Labor Day weekend.  I've read
> theories about a too-deep dipstick tube, or small hole in the dipstick
> tube to relieve pressure, but that was mentioned specifically about
> EMs. Does it apply to LMs too? Any other suggestions?"
> 
> ************************************************************************
> 
> Now for the update:
> 
> The PCV system was clear. A compression check was done, and it showed
> 145-150 lbs on three of the six cylinders. Two of the other three
> showed ~90 lbs, and one was ~65 lbs. My mechanic Tom drove the car a
> bit more, taking out to the 4-lane and opening it up a bit.
> 
> He reported back late in the day Friday 9/3 that the blow-by had
> reduced drastically, and that perhaps we had the rings seating in. He
> offered me the car for the holiday weekend, which I went and picked
> up. The premise was I'd put ~300 miles on it and bring it back up to
> him for another compression check and hot adjust on the valves, which
> had been cold adjusted to within a 1/4 turn per Tom.
> 
> One bank ... the one reading two cylinders low ... was smoking a bit,
> but our thought was maybe the rings were still seating. I drove it
> carefully, generally 3500 revs or less, but never over 4000 while
> upshifting. The mild Isky cam had 5k miles on it already, so that
> wasn't a concern.
> 
> 48 hours and 150 miles after picking it up, I started it and blew
> clouds of oil smoke out of the bank, the one that was slightly smoking
> earlier. Temp stayed normal; no oil light; no clatter other than a
> slight valve tick expected before the hot adjust. I'm convinced I just
> blew one of my brand-new rings, and I'm hoping it didn't score the
> brand-new full fin jug.
> 
> Question: Is it possible to put a ring in 'backwards'? If so, you
> figure a guy that doesn't know the difference would have a 50/50
> chance at it ... and I was reading low on exactly three cylinders
> after a ground-up rebuild.
> 
> Any thoughts and/or advice would be appreciated.
> 
> Jay
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