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Discussion Starter · #1 ·
I've been researching how I would go about building my SC M62 for more boost ( I know an M62 isn't an S62...). Nikasil is a proven motorsports technology and porsche's been using it in their TT cars for quite a while, and the issues with it have been caused by too high sulphur content in fuels (no longer an issue).

Peter's recent issues with what appears to be cylinder ovaling due to the sleeving process (my guess, I have not done any direct investigations), and the head gasket issues David has had with his sleeved engine (less heat transfer due to the sleeves) makes me believe that a thick Nikasil coating with the appropriate Nikasil friendly rings (JE and others make them for their forged pistons) would work with less headaches...

Anyone enlighten me on what I'm missing?
 

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The cost? Last time I checked it wasn't cheap to nikasil coat the cylinders, but that is here in the uk and maybe it's different in the USA.
 

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Nikasil engines and sleeves had pitting problems with high sulfur gasoline. This was mainly a problem in the UK and with cheap gas in the US that has high sulfur content, however, there is also the factor of heat dispersion of Nikasil vs cast iron vs aluminum vs Alusil and its propensity for degradation from moisture. Although supposedly the high sulfur is no longer an issue, you still have the heat dispersion and moisture issue with Nikasil.
The BMW Nikasil issue
BMW ended up replacing the Nikasil engines on the 1992 - 1996/ 840CI M60 engine with the Alusil version. BMW used Nikasil, an Aluminium, Nickel, and Silicon alloy, to line the cylinders of the M60 engines. The cross-hatched Nikasil linings react with high sulfur content found in lower quality gasoline, such as those in parts of the United States. This reaction causes damage to the very top of the bore, where there is the most contact between the combusting fuel and the cylinder lining. The damage prevents a good seal from forming between the piston and the cylinder wall, causing a loss of compression in the combustion chamber. This "leak down" will cause M60's with worn linings will exhibit a rough idle and, if the problem continues unchecked, the engine will not start.
The only permanent fix for this problem is the replacement of the short block with the equivalent block using Alusil linings, which do not exibit this corrosion problem. After the problem was found, BMW issued an extended 6 year, 100,000 mile (160,000 km) warranty to cover these engines at no cost to the owner.
 

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sleeving is fine, assuming you have a worthwhile machine shop; which seems to be very very rare in the case of sleeving OEM aluminum blocks.

I always have said, if your machine shop doesn't have a regular calibration routine with their instruments, find another shop - with the tolerances required for proper engine building, it's an absolute MUST in my book.
 

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sleeving is fine, assuming you have a worthwhile machine shop; which seems to be very very rare in the case of sleeving OEM aluminum blocks.

I always have said, if your machine shop doesn't have a regular calibration routine with their instruments, find another shop - with the tolerances required for proper engine building, it's an absolute MUST in my book.
Agree wholeheartedly about the quality of the machine shop. herrubermensch is living proof of that!!!

But I thought the real question was whether sleeving the block was necessary to get higher boost (and on an M62, not S62). Although the OP doesn't say how much more boost, as I understand it, the problem with the S62 is that the walls between cylinders are very thin, something like 4mm. So if you intend on replacing pistons with lower compression and stronger to add boost, you run into problems if there is any need to do more than the very lightest honing of the cylinder walls, which typically show some wear over time.

Now, if you add sleeves, you then have pristine cylinder walls (the inside of the sleeves) and you also strengthen the block with the sleeves acting as reinforcements, allowing for much higher boost levels, all other things being equal.

As a GUESS, I would say 10-12 psi could be handled by the block (but not the rods or pistons) but after that, I would GUESS the block needs the strengthening of the sleeves.

Since the M62 is not as bored out as the S62,(and starts with lower static compression) I suspect there is more room to clean up the cylinder bores and go to a slilghtly oversized pistons (along with stronger and again, some lowerring of the static compression ratio) without the same need to sleeve the block.

So to the OP, on an M62, I am guessing you don't need to sleeve the block unless you are looking for serious double digit boost numbers.

Regards,
Jerry
 

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Jerry, I agree, My comment was more addressing [what I perceived as] a hesitantly-toned question arising from the risks associated with sleeving a block.
 
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Discussion Starter · #9 ·
Agree wholeheartedly about the quality of the machine shop. herrubermensch is living proof of that!!!

But I thought the real question was whether sleeving the block was necessary to get higher boost (and on an M62, not S62). Although the OP doesn't say how much more boost, as I understand it, the problem with the S62 is that the walls between cylinders are very thin, something like 4mm. So if you intend on replacing pistons with lower compression and stronger to add boost, you run into problems if there is any need to do more than the very lightest honing of the cylinder walls, which typically show some wear over time.

Now, if you add sleeves, you then have pristine cylinder walls (the inside of the sleeves) and you also strengthen the block with the sleeves acting as reinforcements, allowing for much higher boost levels, all other things being equal.

As a GUESS, I would say 10-12 psi could be handled by the block (but not the rods or pistons) but after that, I would GUESS the block needs the strengthening of the sleeves.

Since the M62 is not as bored out as the S62,(and starts with lower static compression) I suspect there is more room to clean up the cylinder bores and go to a slilghtly oversized pistons (along with stronger and again, some lowerring of the static compression ratio) without the same need to sleeve the block.

So to the OP, on an M62, I am guessing you don't need to sleeve the block unless you are looking for serious double digit boost numbers.

Regards,
Jerry
Was looking to get to 12 psi without taxing the internals (would have to do rods/pistons etc...). So the sleeving process is a block strengthening process as well... This is a significant difference from the Nikasil coatings used on Alusil blocks (porsche, corvette CF-r racing engines etc...). I would probably want to bore the engine out a bit to closer to 5 liters, so sounds like sleeving is better especially for the cylinder spacing in our blocks. Now to Matt's point, where to get it done??

Is VAC the only game in town?
 

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It's the only place I'd trust. They've done more S62s than anyone.

--Peter
I would heed his advice. As far as I know, Peter has been by far the most involved board member when it comes to actual hands on communication with suppliers/builders. It would be nice if you could have just anyone sleeve these blocks, but you will have a hard time finding a shop that will sleeve it and stand behind their work.
 

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Was looking to get to 12 psi without taxing the internals (would have to do rods/pistons etc...). So the sleeving process is a block strengthening process as well... This is a significant difference from the Nikasil coatings used on Alusil blocks (porsche, corvette CF-r racing engines etc...). I would probably want to bore the engine out a bit to closer to 5 liters, so sounds like sleeving is better especially for the cylinder spacing in our blocks. Now to Matt's point, where to get it done??

Is VAC the only game in town?
It appears so, at least for now.
I am waiting to see how Peter's turns out before I send mine out.

Regards,
Jerry
 

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Discussion Starter · #14 ·
Aside from VAC, Mr. X is an option, but an expensive one.

--Peter
VAC did David's and so far no issues except head gaskets... Mr.X would be great, but I barely have the coin for him to tune my engine. I don't think a Mr X built engine is in the cards, although I may go with his headstuds...

If you're engine comes out good from VAC, that's who I'll go with when the time comes. Will be enough data for me...

Thanks everyone for your help and guidance, the brain trust on this board is astounding!
 

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just an aside, sinking sleeves can cause headgasket failures. I don't think that was david's issue, though.
 

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Discussion Starter · #16 ·
good to know... I think David's issue was not retorqued heads after a few heat cycles... We'll see they're about back together!
 

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good to know... I think David's issue was not retorqued heads after a few heat cycles... We'll see they're about back together!
Retourqued Head studs? You can't be serious. I might be completely off base here, but I know the factory doesn't do this, and no ARP or OEM head bolts/studs have ever recomended this.

Please someone teach me the wrongs of my ways.
 

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Retourqued Head studs? You can't be serious. I might be completely off base here, but I know the factory doesn't do this, and no ARP or OEM head bolts/studs have ever recomended this.

Please someone teach me the wrongs of my ways.


hot torquing is a fairly common practice.


Consider stretching/tightening your studs on a fresh engine (to manufacturer spec, of course), then heat cycling the engine a few times. As everything expands and moves around, you're likely to see a bit more stretching. With that said, I've had a few machine shops recommend re-torquing the head studs while warm after a few break-in-style heat cycles.
 

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I understand why and can see the theory behind it, I've just never heard of it being the reason behind a failure or a recomendation to prevent it.

I would be terrified of snapping one off.

Thanks for the info though.
 

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Very common. I don't do it with factory stock rebuilds. However any ARP build gets a re-torque after heat cycling. These need to be torqued in a very specific fashion... Lots of different theories on different torque procedures, but this can be a common failure point.

VAC builds some great motors, and Tony is a good guy over there. IMO they are the only shop I'd trust for shortblock work. They've got everything in house, and in my experience have very fast turn around time.
 
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