On Fri, 24 Aug 2001 14:46:44 -0400 "James H. Nazarian, Ph.D."
<microdoc@apk.net> writes:
> IMHO, if the engine needs to be rebored because one or more cylinders
> are worn out of round, deeply scored, or otherwise damaged, yet the
> pistons and their grooves are in good shape, I would be more
> inclined to have the cylinder, or cylinders "sleeved". An automotive
> machine shop can install a sleeve for little more than the cost of a
> cylinder re-bore, while saving you from buying a new set of pistons,
> etc. Furthermore, the sleeve that Moss sold to me several years ago
> was a Mazda OEM part. I assume that there
> were some metallurgical improvements imparted to my 1974 British
> engine by the use of a 1994 Japanese sleeve; only time will tell.
> The cost savings, however, were substantial and immediate.
I'm not sure I would sleeve a block just to save the cost of new pistons.
Sleeving requires overboring the cylinders then having a sleeve put in
place through an "interference fit." The sleeve is also kept from moving
around by the head on top and a "step" on the bottom of the cylinder. If
something goes wrong in the sleeving process the bottom step can be
broken. You then risk the sleeve moving down into the block and leaving
a gap at the top and eventually fouling something. The sleeve can then
be welded in place, but you are welding it to cast iron, which is a dicey
thing.
How do I know all this? Because my MGA 1622 block is sitting in a box
with a broken step and a welded sleeve and it needs a new set of sleeves.
My machinist said he "couldn't be responsible" for the result and felt
that it would not be a very durable engine.
Of course, if the cylinders are too badly worn or scored, you'll have no
choice but to sleeve the block. I just wouldn't take the risk to avoid
the cost of new pistons. My machinist quoted me about $100 per bore to
sleeve a block, but I don't recall how much to bore each cylinder. 1275
pistons are not all that expensive at less than $200 from Moss (with
dealer discounts). And then you would have new pistons with new wrist
pins, etc.
Just MHO.
David Littlefield
'62 MGA MkII
'51 MGTD
'74 MG Midget vintage racer
'88 Jaguar XJ-S
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