Tech: Are cylinder sleeves bad for your S65 engine?

[Brian_VACsales]

See more on our blog: http://www.vacmotorsports.com/blog/a...ur-bmw-engine/

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.

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.

[THE TECH]

Without reading this I would have said that sleeves are a non-issue as long as installed properly. I think installation is where the issues lie.

[Brian_VACsales]

Sleeve design too

We get a lot of questions re. sleeves so it made sense to do a blog post with some info.

[THE TECH]

Originally Posted by Mike@VAC

Sleeve design too

We get a lot of questions re. sleeves so it made sense to do a blog post with some info.

Yeah, definitely a nice thread.

[Orange fever]

Good reading

[IMG]

I've seen some sleeved motors done by VAC and looks great .
What are the bore centers of the S65 and what is the maximum bore you can use with these sleeves?

[m3an]

Originally Posted by img

I've seen some sleeved motors done by VAC and looks great .
What are the bore centers of the S65 and what is the maximum bore you can use with these sleeves?

good point, doesn't really look like much room for anything over a standard bore. Are these blocks could for at least 20-30 overbore if needed? Or does it have to be scrapped? those cylinder walls are thin

[disruptv]

what abt for the s85 engines?

[ChrisDUS]

Originally Posted by disruptv

what abt for the s85 engines?

The same should apply as S85s are more or less S65s with 2 more cylinders.

[OM VT3]

Do you think if you did this to a stock motor and had an ess supercharger you would be able to run maybe 10-12 psi

[mkoesel]

Originally Posted by img

What are the bore centers of the S65 and what is the maximum bore you can use with these sleeves?

I'm not a VAC employee, but to answer that first question, all BMW V8s have a 98mm bore center (as an aside all of their modern I6's, i.e. M20 and its successors, have a 91mm bore center).

Not sure about the maximum bore with VAC sleeves, but an S62 has a 94mm bore so that's just 4mm material left between cylinders. Ergo, you can do better than the S65's 92mm bore. Not sure if sleeving will allow you to go past 94mm, but the point of the sleeves is to increase strength anyway.

[benzy89]

Originally Posted by leigh

Do you think if you did this to a stock motor and had an ess supercharger you would be able to run maybe 10-12 psi

+1, how much more boost can you run & then expected gains?? Since the sleeves reinforce the cylinder walls & you said that the pistons would hold up

[m3an]

I would imagine more than 10-12lbs and more like 20lbs!!

[Stealth ///M]

Originally Posted by leigh

Do you think if you did this to a stock motor and had an ess supercharger you would be able to run maybe 10-12 psi

That's pushing it without adding some serious octane AND METHANOL, however I still wouldn't try it. The stock compressing ratio is too high, 12:1 , to try and squeeze that must boost into the motor = detonation.

My last motor build for twin turbo 5.4 liter, 9.5:1 comp ratio. This was a 16 vale single overhead cam v8. I planned on making 1000 rwhp.

Initial testing yielded 680 rwhp: 720 lbs tq on 10si with pump gas. Car drove stock and was a pleasure

With race gas and 15 psi, we surpassed 850 rwhp and 900lbs.

Unfortunately, the car was t-boned while being driven to the shop, and the project was scrapped and sold to someone.

Anyway, no. I wouldnt EVER try to hit 10-12psi on a stock s65 motor.

[OM VT3]

Originally Posted by Mike@VAC

See more on our blog: http://www.vacmotorsports.com/blog/a...ur-bmw-engine/

There seems to be a bit of controversy surrounding cylinder sleeves and BMW engines.

...

mike, say you were to sleeve an s65 and do nothing else to it how much psi do you think the motor would take? i know you would need a fuel system and maybe some other stuff or do u think it would be better to change the pistons and rods

[Brian_VACsales]

Once you commit to sleeves everything has to come apart. Pistons and rods are mandatory in our opinion

No one has pushed a S65 too far yet...so who knows. Sleeves can handle a ton of hp, there are dozens of 1000+hp BMWs on sleeved blocks out there. There are thousands of sleeved non BMWs out there making crazy power. Sleeves are not the issue.

[benzy89]

Originally Posted by Stealth ///M

That's pushing it without adding some serious octane AND METHANOL, however I still wouldn't try it. The stock compressing ratio is too high, 12:1 , to try and squeeze that must boost into the motor = detonation.

Originally Posted by Mike@VAC

Once you commit to sleeves everything has to come apart. Pistons and rods are mandatory in our opinion

So since most of these kits are running the highest "safe" boost on stock compression (between 6-8 psi), sleeves might as well be mandatory (in addition to forged pistons & upgraded rods) in a low-compression, high HP build. Not like moneys going to be an issue when someones doing this kind of upgrade & it's a smart way to make sure nothing breaks