<VV> Total Seal rings and turbo oil smoke

[Mark Durham]

Jim, the dynamics of using a quart every 800 points to the fact that
the Moly rings never seated properly And you have always used more oil
than you should. You say they honed the cylinders extra for the Moly
rings, probably due to the fact that Moly works better with a different
cross hatch pattern, finer, I think, and if that is the case there are
two things that could be a potential problem, the hone job was botched
which ate up your rings, and honing took the barrel diameter to the
outside of the limits which lowers tension on the barrel walls.

Also a potential problem is the .040 barrels, that could have warped
over time due to the extra turbo heat. If a top overhaul is not in you
near future, go buy some 20/50 oil and put in with a new filter. Drive
it for a bit and see if the higher viscosity oil slows the smoking any.
Mark Durham
Sent from my Windows Phone
From: Jim Simpson
Sent: 6/23/2012 11:03
To: Virtual Vairs
Subject: Re: <VV> Total Seal rings and turbo oil smoke
It seems that several people have zeroed in on the Total Seal rings as the
most likely cause of the idling oil smoke on my '66 turbo engine.

The engine has about 15k on it, having been totally rebuilt as part of the
car's restoration.  I did all the wrench work, but I sent the cylinders to
OTTO Parts (back when they were still in business) to be bored 0.040" over
and have TRW forged pistons fitted.  They honed the cylinders knowing I was
going to use Total Seal moly rings.  I installed the moly ring in the
second groove per Total Seal's recommendations for a turbocharged engine.
I did check ring end gaps and groove clearances, but don't ask me what they
were -- the engine was assembled in the mid-80's and then sat on the bench
for years while the rest of the car came together and I didn't take a lot
of notes at the time.

The engine was broken it driving it to the Lake Placid CORSA convention in
'97 (about 600 miles from here).  I kept mostly to two-lane roads so RPMs
would be varied and not have to push the engine hard during the break-in.
It ran a bit warm, but settled out after the first 500-1000 miles.  Since
then it's run well.

A few years ago I did some instrumented runs with the engine, measuring
fuel/air ratio, throttle position, manifold pressure and RPM.  (I had a
four channel analog-to-digital data converter and a laptop.)  Fuel/air
ratio was very good, a touch on the rich side as it should be for a turbo.
The turbo produced just under 11 psi boost in 4th.  This is with an
essentially stock engine other than the .040" bore.

I've owned this car since '68 (second owner) and driven it coast-to-coast a
couple of times.  I've kept records on it all this time.  During the time
I've owned it, it has been rebuilt once with stock GM
cylinder/piston/rings, the heads were replaced once due to a dropped valve
seat, and most recently the complete overhaul.  Oil consumption has been
pretty consistent at ~800 mile a quart over all this time which tells me
that the majority of the oil consumption has been due to seepage in the
turbo.  (At least the oil keeps the valves and cylinder tops lubricated.)
Once the engine was broken it, I've used Mobil 1 10w-30 changing annually.
(That's changing it about every 1000 mile -- seems like overkill.)

Since the oil smoke started up over the last year, I really haven't put a
lot of miles on the engine so I can't say with any certainty just how much
oil it's consuming right now.  (We drive it to shows and plan to be at
Sturbridge this year.)  But it certainly doesn't seem to have made a
quantum leap in consumption.  I'll keep an eye on it though and be sure we
have several spare quarts with us on the trip to Sturbridge.

I guess my next step is to do a compression check to see if that tells me
anything.  But if the compression rings are still intact (and I can't
imagine they've worn significantly) and it's something like ring flutter or
that the gaps on the total seal rings have walked their way around into
alignment, I'm not sure that would show up in a compression check.

Suggestions I've received include changing the timing by a couple of
degrees either way and increasing the idle speed.  I'm not sure why either
of these would affect idle oil consumption; perhaps there's something
strange going on with the rings at particular speeds.  I'll give these
suggestions a try as well.

Of course there's still the possibility of a bad carbon seal in the turbo,
but the opinions I've received suggest that was the problem the oil smoke
would get worse at speed.  There doesn't seem to be visible oil smoke while
cruising so perhaps that rules out the turbo.

So that's the progress so far.  An engine tear down is at least two years
away short of a catastrophic failure and I can live with the oil smoke for
a while.  (It is a bit embarrassing sitting at a stop light with clouds of
oil smoke wafting out of the rear...)

Any other suggestions or ways to diagnose the problem are more than welcome.

Jim Simpson
Group Corvair
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