There seems to be a bit of controversy surrounding cylinder sleeves and BMW engines.
Oil consumption, excessive noise, sleeves dropping, Alusil blocks not liking sleeves
– you name it. I took some time to talk to our machine shop foreman, (the
man with 50 years experience) Tony (VAC owner) and our manufacturing partners (Darton
and LA Sleeve) about the drawbacks of using sleeves in the S54, S62 and S65 engines.
Short answer: There are no drawbacks.
Long answer: I can say with absolute confidence that properly specified
sleeves installed properly will work flawlessly and offer more durability than a
non sleeved block. Track builds, street builds, stroker builds, big HP forced induction
builds – not a problem. We have sleeved dozens of BMW engines in our machine
shop and sold 100s of BMW sleeves to machine shops all across the world. We always
have a few shelves full of BMW sleeves ready for shipment.
Some quotes from our partners:
“The only drawbacks we are aware of are poor installation practices. It’s
the primary reason for almost every issue possible. Let me address that first: by
adding a foreign object to the block, which had nothing in it to start with, logic
would say the block has been compromised. That can be true if done incorrectly.
Oil consumption is a myth. In many cases, oil consumption will increase as a result
of sleeves because of an incorrect hone pattern. But, noise isn’t a myth.
If the sleeves are installed with too much piston to wall clearance, it usually
sounds louder during warmup. It sounds louder as a result of iron lining the cylinders.
Only way to prevent that is to watch the piston to wall clearance during the honing
of the sleeves.
Only other issue is the sleeves dropping – It’s rare but possible. Easily
preventable, as long as they’re installed properly. Only thing that can drop
the sleeves, even after perfect installation, is bad aluminum and/or when a block
is overheated all while the head has been over-torqued. What we’ve seen happen
when a block is way over torqued, and a customer is paranoid about head gasket seal,
they’ve over-torqued their head thinking it will seal water. So, when the
heat expands the block, the block will pull away from the head. As that happens,
the expansion along with the over-torqued head, it will actually push the sleeves
down because the sleeves seem to rise at the same time. Very rare, but again possible.”
For all builds, we take it one step further by using flanged sleeves, built to our
exact specs. These flanges assure that the sleeve will not ‘drop’ under
any circumstances. See pics below.
“When some mechanics or engine builders look at the deck of the S65, they
think there’s no room to put sleeves. Although the S65 does not have thick
walls in between cylinder bores, it does have one good quality – hard aluminum.
If the sleeves are installed properly, the block looses no structural integrity.
Meaning, the performance sleeves are quite thin, but radically stronger than the
S65 aluminum. Therefore, by installing the thin wall sleeves properly, the great
S65 block is now much more receptive to higher volumes of boost than the S65 alloy
can handle. By simply lining the block with the thin wall, centrifugally spun-cast
ductile iron sleeves, the cylinder bores can handle 50% to 70% more boost than that
of the Alusil aluminum bore block.
The boost can care less what pistons it runs with in most cases. It’s the
cylinder block walls that are compromised first, not pistons. If the S65 block aluminum
is poor, it will fracture the block well before the pistons fail. That’s why
we like to re-sleeve these alloy blocks ductile iron material. Not to save the pistons,
but so the block can hold compression so the pistons do their job properly.
There are several reasons for using cylinder sleeves. Most commonly they are found
in manufactured aluminum blocks because as you know aluminum does not have the wear
or sealing properties needed unless it is coated.
In higher performance applications a ductile iron sleeve is preferred since they
are at least twice the strength of a standard cast iron sleeve. If the sleeve is
designed properly to fit the block the strength can actually be increased in the
bore and ring seal is greater. You will also be able to run any style piston and
ring that best suits the application. In some cases sleeved blocks will allow you
to achieve a larger bore size or clean-up any damage that may occur. They can also
be replaced in most cases.”
Yes, we sleeve Alusil engines with confidence.
There ya have it – direct quotes from BMW engine and sleeve experts. Please
visit us at 2515 Snyder Ave to see well over 1/2 million dollars of BMW engine
components on our shelves. You will also see a few million dollars
worth of the best machine shop equipment available.
Flanged sleeves, made to exact VAC specs are measured before machine work starts.
S62 block is honed and ready for the flanged cylinder sleeves.
Very precise machine work is standard at VAC.
Flanged sleeves are installed in the S62 block ready to be honed.
S65 sporting VAC specified Darton flanged cylinder sleeves.
Sleeved S65 on our RMC V40 machine.