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

Fri Sep 10 08:33:21 EDT 2010

Total Seal rings!  What grit size were the cylinder honed to?  I once had a very similar problem.  I called the Total Seal Tech Center and before I could even finish the story, their rep told me that unless I used a minumum of 400 grit the rings would never seal and I had destroyed them.  The cylinder which I had bought from the big NE guy were at 280 grit.  Ever since I've used a 400 grit ball hone without any problems.  Just a thought.

---------- Original Message ----------
From: Jay Pitchford <jay.pitchford at gmail.com>
To: Virtual Vairs <virtualvairs at corvair.org>
Subject: Re: <VV> Advice on Rings (was Help - Oil Out Dipstick Tube)
Date: Fri, 10 Sep 2010 07:14:41 -0400

Tony - I'll try to answer some of your questions and comments below.
It'll be all caps to make it easier to find/read. Please understand
I'm not yelling :-)

On Thu, Sep 9, 2010 at 3:10 AM, Tony Underwood <tony.underwood at cox.net> wrote:
> At 10:21 PM 9/8/2010, Jay Pitchford wrote:
>
> 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,
>
> That's pretty low...
>
> and one was ~65 lbs.
>
> That's WAY too low.

THAT 65 NUMBER IS FROM DIM MEMORY. I RECALL THAT THE PASSENGER BANK
HAD TWO LOW AT 90, AND THE ONE ON THE DRIVER'S BANK WAS SIGNIFICANTLY
LOWER THAN THAT.
>
> 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.
>
> Are all the low cylinders on the same bank, or is one low cylinder on the
> opposite bank?

ONE LOW ON DRIVER'S SIDE, TWO LOW ON PASSENGER SIDE.
>
> 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.
>
> The low compression is a bit alarming for a fresh engine.   What do the
> cylinders test now, after some miles?

WE WILL FIND OUT LATER TODAY. CAR GOES BACK TO SHOP (55 MILES ONE WAY
ON FLATBED) LATER THIS AM. COMPRESSION CHECK IS ITEM #1 ON THE LIST.
>
> Question: Is it possible to put a ring in 'backwards'?
>
> Unless they're exotic compression rings, (Dykes rings etc) it's not gonna
> cause that much trouble.  They do have (or most do) a marker dot on them to
> indicate which side is "up", but it's not very likely to make THAT much
> difference if the compression rings are installed upside-down.   Depending
> on type, oil rings CAN be an issue but if they're the standard 3-piece oil
> rings (not the cast one-piece), they won't care.   They won't have much
> effect on compression anyway.
>
> 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.
>
> Exactly what kind of rings are these?   Are the compression rings cast iron
> or moly-filled?  Cast iron rings can break VERY easily, while the
> moly-filled rings tend to be less brittle and will usually bend before they
> break.

THESE ARE TOTAL SEAL MOLY RINGS FROM CLARK'S. I ALSO PURCHASED NEW
FULL-FIN .030 JUGS, NEW FORGED PISTONS, RODS, AND BOUGHT THE CLARK'S
PISTON PRESS-ON SERVICE.
>
> When the pistons went into the cylinders, did they go in from the top or the
> bottom of the cylinders?    What sort of ring compressor was used?   This
> could be important...
>
I DON'T KNOW THE ANSWER TO THAT.
>
> ...did you check clearances on the cylinders, just to be sure?   Three that
> low doesn't sound right at all.  Even before rings seat, you should have had
> more compression than what your low cylinders are showing, right after the
> first cranking and start-up with NO break-in at all, especially that one
> very low cylinder.   That one is only trapping a bit more than 4
> atmospheres... something went wrong there.   I wouldn't expect too much
> lower compression than 65 lbs if there were NO compression rings on that
> particular piston.
>
I CAN'T SAY WHAT CLEARANCES WERE CHECKED, BUT THIS GUY DIDN'T FALL OFF
THE TURNIP TRUCK YESTERDAY. HE'S BEEN WORKING AT THE SAME GARAGE - AND
NOW OWNS IT - FOR OVER 30 YEARS.
>
> ...what's the story on the cylinders?   Again, were piston clearances
> checked before assembly?   And were the cylinders prepped as they should
> have been?   You mentioned they were new... is that new as in NEW or are
> they fresh rebores?

NEW AS IN NEW PER ABOVE.
>
> Any thoughts and/or advice would be appreciated.
>
> The smoke speaks volumes.   If the heads are OK (you said M. LeV. did them
> so they should be fine) I'd not think the smoke would be from guide
> clearance... the guides would need to be worn pretty bad to make "clouds" of
> smoke on start-up but it's not likely they would cause such a difference in
> compression without other symptoms as in noisy valves if the guides were
> loose enough to allow the valve to wobble and not seat...

MICHAEL LEVEQUE PUT NEW BRONZE GUIDES IN. I AGREE THAT IT'S HIGHLY
UNLIKELY THE HEADS ARE THE SOURCE OF ALL THAT OIL SMOKE.

If the valves
> themselves were simply leaky, and causing the low compression, it still
> wouldn't cause smoking and/or blowby without the accompanying loose
> guides.    I'd suspect the heads are OK in this instance and I'd go with
> something wrong with cylinder sealing... smoke generally means bad ring seal
> or loose clearances,

ONE OF THE REASONS WE STRUGGLED TO SAVE THE BLOCK, DESPITE THE UPPER
STUD PULL, WAS THAT IT MIC'ED OUT SO BEAUTIFULLY ON TOLERANCES. LARRY
CLAYPOOL'S INSERTS WERE A GODSEND. I BOUGHT SIX, AND WE ONLY USED TWO.
I'LL STORE THE REST AND 'PAY FORWARD' TO SOMEONE ELSE WHO NEEDS THEM.

piston/cylinder or worn/cracked rings... which are in
> this instance new but if something went wrong, all bets are off.    The
> blowby kinda confirms that as well.   Low compression?   It speaks for
> itself... time for another compression check.   Something is wrong in those
> three holes.   I don't think you need to look at the heads.
>
> By the way, whenever I have a pan off or an engine apart, when it goes back
> together I stick a #2 phillips screwdriver into the bottom of the dipstick
> tube where it extends down into the crankcase and I snap it off.   Then I
> "ream" out the bottom of the tube with the same screwdriver to make sure
> there's no burs or kinks.    The tube can stick down far enough to dip into
> the oil in the pan and if there's blowby the crankcase can pressurize enough
> to push oil up and out of the dipstick, if the engine is given any major
> throttle openings under load... even with a functioning crankcase vent
> system.
>
> Check that compression again and let the group know what you find.
>
I WILL REPORT BACK LATER TODAY OR MONDAY, AS SOON AS I GET MORE INFO
TO FEED BACK TO EVERYONE. THANKS TO ALL FOR THE ADVICE, SUGGESTIONS,
AND SUPPORT . . . . JCP
>
> tony..
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