62vair at gmail.com
Wed Nov 24 23:34:12 EST 2010
Ned, there reallyt are no tricks. If you want stock, meaning standard
bore, there are four possibilities:
1. Mike out your cylinders and see if they are stock bore. You can re
ring with a bore up to .005 larger honed and ready to go. If you see
multiple ring steps on the cylinder walls, they will not be stock.
Or find a set of used cylinders that are standard bore if yours are not.
2 try to find some 1960 cylinders that have been bored to 61-69 bore
size, which is standard bore. I tried and could not find them.
3. buy a set of Clark's full fin cylinders in standard bore. Costly,
but you get what you pay for.
4. Or, you can realize that a .020 overbore is not a significant
change from stock and is actually less expensive, either through
Clarks Cyl/Piston/Ring kits, or I just ordered mine thru LS
Enterprises for a bit less, but mainly because I am a west coaster and
didn't want to pay shipping for the heavy stuff then pay again to ship
cores all the way to MA.
Just know that to have a good running engine means you need to
maintain new clearances when you put the engine back together. For
example, My engine with only 69K miles on it (and 48 years old) had
had done what you want to do. They honed the cylinders and put new
pistons and rings in, and yes, it lasted awhile, but I'm having to do
it all over again now because they took shortcuts. I had ring end gaps
at +.060, and the oil control rings just fell through the cylinder
when I went to check its end gap. Yet I had 145 compression on 4 and
125 on two that would go to 150 when you squirted oil in the barrels
for a test. But, it was using lots of oil and puffing on startup.
Also, if you do not know the history of the engine, check that cam and
lifters closely. Mine had hundreds of tiny rust spots all over the
polished surfaces, looked good down through the top looking around the
crank, but I had three lobes over .020 to .030 shorter than the rest
and the metal had gone through the bearings and scratched the crank
enough it needs turned. Also, I found corrosion/rust pits on the ends
of all the valves where the rocker sits, probably from the car sitting
so much for the last 20 years.
Just be mindful to look at it all, because if you knowlingly take
short cuts,or decide not to look, you may end up taking it apart
again too soon.
But then, you might be right and it may only need re-ringed. Look, and
do what is necessary. Get the correct engine manuals. Keep to the
new tolerances. You'll be OK.
Regards Mark Durham
On Wed, Nov 24, 2010 at 4:39 PM, <AeroNed at aol.com> wrote:
> My winter project is going to be the rebuilding of a 95 hp engine to go in
> my 65 coupe. This engine will be hooked to a PG and will be running AC. The
> "core" engine is a runner that smoked when removed. I'm thinking it may
> only need rings (and new bearings and other while I'm there parts).
> Anyhow, I've heard all sorts of stories about re-ringing a Corvair engine,
> most of them bad. I'd like to hear some of the good ones. I really would
> like to keep the bore stock. What are the "tricks" I'll need to know to do
> this right.
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