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Discussion Starter #1
discovery-automotive managed to put together a sleeved M5 block. Something that many said could not be done. Here are the pics...

 

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Of course it can be done, but what is the result?

Since these dry sleeves are super thin & less than 1.5mm thick between cylinders, it will be interesting to hear any feedback about it's in-service performance parameters. These sleeves will not transmit combustion heat to the surrounding metal anything like the plated one piece OEM cylinders. Dry sleeves change shape when subjected to elevated power & temps. As such, ring seal (blowby) & head gasket seal is invariably compromised. It's been my experience that dry sleeves are at the bottom of the pecking order, below wet sleeves (Cadillac etc) and definitely below one-piece plated designs used by BMW and Porsche. Hot rodders & mfrs abandoned this technology for performance motorcycles and cars 30 yrs ago. Maybe some new process has been developed to improve heat transfer such as injecting Pentium 4 heat sink compound during the sleeve-pressing process (lol).

This recipe has been tried thousands of times & results are consistently poor.

My initial assessment is it looks like a good way to "save" a damaged block (otherwise worth $10K) for reuse in a car going to auction or a used car lot.

If my opinion off base, I'd like to hear why.
 

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My guess is; this is a must to load some serious boost, for example to be able to use HQ stainless piston-rings - sleel sleeves is a must else they will "eat up" the alusil coating ...

(did I say I'am doing the same on my M62 block... but a bit thicker walls and also using flanged sleeves)
 

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Discussion Starter #5
The car will be pumping 15-18 psi and it could be alittle more now with the sleeves
 
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Black M5 said:
The car will be pumping 15-18 psi and it could be alittle more now with the sleeves
Who do you expect will win the HP war? Is it you or Tri?

Cheers, Daniel.
 

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i'm not an engine builder but i have seen and been around motor builders , those sleeves look mighty close to each other, they are going to expand and contract a little under load right?
hmm..
i hope it works out it would be a great success if it did!

ray
 

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Of course it can be done, but what is the result?
My thoughts, too. The etched bore design I think is superior in most respects. Only hot rodders who like to bore out their own blocks dislike this because they can't. :M5launch:
 

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Discussion Starter #9
BeastPower said:
Who do you expect will win the HP war? Is it you or Tri?

Cheers, Daniel.
 

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Need4Spd said:
My thoughts, too. The etched bore design I think is superior in most respects. Only hot rodders who like to bore out their own blocks dislike this because they can't.
I don't see much benefit to sleeving a block that doesn't have bore-wall-thickness problems.

At the same time, there's really nothing wrong with it so long as the sleeve can be properly retained in the block and that block expansion/contraction does not result in the sleeve 'pulling away' from the head - usually a rib or step at the top of the sleeve and a counterbore in the block. IIRC Darton did these sleeves, and I'd have no trouble trusting their stuff.

It is possible to resurface an Alusil bore, though I think few shops are set up to do it, and in the S62's case there isn't room to bore it anyway.

It might be a matter of piston sourcing and piston/wall compatibility.

Sleeves are at least replaceable if something does go wrong...
 

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Lscman said:
wet sleeves (Cadillac etc) and definitely below one-piece plated designs used by BMW and Porsche.
Plated? What's plated?

The S62 block is Alusil, same stuff as the Vega engine. High-silicon alloy with the soft aluminum etched off the bore surface. No plating.

BMW has used Nikasil/Galnikal bore coatings on their bikes for decades, but it flopped completely on the M60 V8 circa '94-95 when confronted with gasoline with any kind of sulfur content, so they went back to Alusil.

Jaguar did the same thing a few years later (!) with the AJ-V8, had exactly the same problems, and went to a dry-liner block.

'Hot rodders and mfrs' did not abandon this technique decades ago, there's almost an infinite variety of sleeved blocks running around out there.

To my knowledge the air-cooled Porschies use Galnikal but the water-pumpers are Alusil, in fact IIRC Porsche bought the rights to the technology from GM after the Vega debacle (which was caused not by a fault in the basic technology, but - among other faults in the Vega engine design - by GM's use of an iron cylinder head and a cheap head gasket that could not accommodate the expansion/contraction of the aluminum block.)
 

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On the other hand is Porsche known for good quality and have used Nicasil coatings since 30 years back or something like that... :)
 

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JEM said:
Plated? What's plated?
Sorry for the poor "descriptor". Many are familiar with the sorted history of the Vega cylinders & the spinoff 928 motor (lol). Maybe the uprated 140 HP 4 valve DOHC Cosworth version got them excited! I was comparing sleeved vs non-sleeved engines in general. There there are many methods used to improve non-sleeve cylinder wear resistance. Performance motorcycles and cars have been utilizing cylinder coatings, heat preps, platings & chemical treatments of various kinds.

I would like to hear how this S62 setup avoids classic dry sleeve issues.

My concern is that thin dry sleeves generally have shortcomings because they do not effectively conduct/transmit heat to the water jacket. A dry sleeve is like installing a heat sink without heat conducting compound.
 

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I'll guess we have to wait and see, at least I will know how it worked by personal experience - in a couple of months or so. :)
 

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Lscman said:
Of course it can be done, but what is the result?

Since these dry sleeves are super thin & less than 1.5mm thick between cylinders, it will be interesting to hear any feedback about it's in-service performance parameters. These sleeves will not transmit combustion heat to the surrounding metal anything like the plated one piece OEM cylinders. Dry sleeves change shape when subjected to elevated power & temps. As such, ring seal (blowby) & head gasket seal is invariably compromised. It's been my experience that dry sleeves are at the bottom of the pecking order, below wet sleeves (Cadillac etc) and definitely below one-piece plated designs used by BMW and Porsche. Hot rodders & mfrs abandoned this technology for performance motorcycles and cars 30 yrs ago. Maybe some new process has been developed to improve heat transfer such as injecting Pentium 4 heat sink compound during the sleeve-pressing process (lol).

This recipe has been tried thousands of times & results are consistently poor.

My initial assessment is it looks like a good way to "save" a damaged block (otherwise worth $10K) for reuse in a car going to auction or a used car lot.

If my opinion off base, I'd like to hear why.
Lscman and I do not always see eye to eye on matters technical, but he has the physics correct here. I might have put the likelihood of a bad result at 95% instead of the 100% implied in the post.

Heat rejection is a big issue on modern high-output engines, and it becomes bigger still as power level is increased without compensating changes to the water and oil systems. Reduce compression ratio for supercharging and proportionately more of the fuel energy goes into the cooling system. A pressed-in steel dry liner in place of a monolithic high-conductivity aluminum cylinder wall will make the issue worse. It might be ok on a stock engine in a temperate climate but maybe not. Here we are talking about doubling the power and thus the amount of heat that must be transferred to the water jacket.

The added fact that the liner is thinner than typically used, made necessary by the tight bore spacing of the S62 block, is also moving in the wrong direction. A thin liner will more likely distort under load; heat transfer to the jacket water will be further compromised if clearance develops under load between the liner and the underlying aluminum structure. This will cause local overheating of the liner, which will be self-aggravating.

Sad to say, but the S62 block design is pretty close to the limit as it comes from BMW. And without doubt, the hot rodders among us would rather be playing around with cast iron bore surfaces than the rather delicate and not real forgiving Alusil. A case can be made for a custom block, aluminum billet with wet liners or maybe even an iron casting, if the ultimate S62 were the plan. But then a Chevy would cost so much less and would probably fit.

Regards, Dick Roberts
 

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Need4Spd said:
My thoughts, too. The etched bore design I think is superior in most respects. Only hot rodders who like to bore out their own blocks dislike this because they can't. :M5launch:
Here is a explanation of the Alusil (late BMW) vs Nikasil (early BMW) bore finish in these websites.

www.e34v8.org/530i-test background-metallurgy.htm

www.bmwseven.com?alum_engine pdf

Or jsut type a search for alusil and you will get all kinds of info on the topic.
 

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JEM said:
I don't see much benefit to sleeving a block that doesn't have bore-wall-thickness problems.

At the same time, there's really nothing wrong with it so long as the sleeve can be properly retained in the block and that block expansion/contraction does not result in the sleeve 'pulling away' from the head - usually a rib or step at the top of the sleeve and a counterbore in the block. IIRC Darton did these sleeves, and I'd have no trouble trusting their stuff.

It is possible to resurface an Alusil bore, though I think few shops are set up to do it, and in the S62's case there isn't room to bore it anyway.

It might be a matter of piston sourcing and piston/wall compatibility.

Sleeves are at least replaceable if something does go wrong...
So many comments, I always enjoy the feed back from others.

In this particular case the specifications for and the fabrication of the sleeves was contracted through Darton with a clear understanding of the original block being used, the associated spec’s, and the intended use of these vehicles once completed. There is no doubt that many issues were taken in to consideration during the evaluation process as such I have every reason to believe that the results will remain wonderful.

The sleeves are in fact flanged so that once the heads were installed the system became completely interlocking; they can not pull away from the head. Now with regards to expansion and contraction comments, certainly this was discussed as such a sleeve with a specific installation process was devised. Now to the issue of dry/wet liners, close proximity to one another, heat dissipation, etc……… fortunately a team of “Smart Cookies” pulled out the slide rules and then looked at, considered, and addressed these issue too. If we can walk on the moon we can certainly properly install sleeves in an M5 motor with the greatest of success.

As for why, there are numerous upsides to the sleeves including as was mention an aggressive chrome ring to seal the combustion cylinders, better cylinder lubrication, serviceability, etc. If anything, the OEM Alusil coating is what many would consider a margin call for motors this extreme. In the case of these motors the Alusil was originally removed in favor of a NiCom coating process however it immediately presented a compatibility concern with the chrome ring….particularly the oil control.

Thank you all again for all the comments; the concerns have been well noted, the support is recognized and appreciated, however through it all the process moved forward methodically, well thought out, and with the support and blessing of many towards the completion of these very extreme Supercharged M5’s.

Take care,

Shadowman
 

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RRoberts said:
Lscman and I do not always see eye to eye on matters technical, but he has the physics correct here. I might have put the likelihood of a bad result at 95% instead of the 100% implied in the post.

Heat rejection is a big issue on modern high-output engines, and it becomes bigger still as power level is increased without compensating changes to the water and oil systems. Reduce compression ratio for supercharging and proportionately more of the fuel energy goes into the cooling system. A pressed-in steel dry liner in place of a monolithic high-conductivity aluminum cylinder wall will make the issue worse. It might be ok on a stock engine in a temperate climate but maybe not. Here we are talking about doubling the power and thus the amount of heat that must be transferred to the water jacket.

The added fact that the liner is thinner than typically used, made necessary by the tight bore spacing of the S62 block, is also moving in the wrong direction. A thin liner will more likely distort under load; heat transfer to the jacket water will be further compromised if clearance develops under load between the liner and the underlying aluminum structure. This will cause local overheating of the liner, which will be self-aggravating.

Sad to say, but the S62 block design is pretty close to the limit as it comes from BMW. And without doubt, the hot rodders among us would rather be playing around with cast iron bore surfaces than the rather delicate and not real forgiving Alusil. A case can be made for a custom block, aluminum billet with wet liners or maybe even an iron casting, if the ultimate S62 were the plan. But then a Chevy would cost so much less and would probably fit.

Regards, Dick Roberts
You are right about the bore spacing and the unusual shape of the sleeves. Look at the old post below (#117) and you will see the issues of sleeving the block.
It would be interesting to see the actual sleeves used by Bill or a drawing of the side and top view. It seems like you would end up with different wall thicknesses as you went around the bore (thinner on the sides between the bores and might have an out of round bore once it got some heat (boost hp).
It's a tough project with lots of effort to overcome the issues of repairing a block not designed to be repaired with a sleeve. My hat's off to Bill for being persistent and coming up with a solution.

John



#117
jeeperjohn
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Join Date: Jan 2003
Location: Valencia, Ca. 91354
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View My Car! BlackM5 block

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Abdulla,
I live about 2 miles from JGM and went over to talk with Jim (owner and a straight arrow guy) about what I had heard and to give him the heads up on this BS. I saw the M5 block and no work had been done on it other than it beiing measured for sleeves. Remember, BMW V-8s do not have sleeves and run on a thin plating applied to the cylinder wall, so the block would have to be bored out (usually 3/16" to 1/4" or 4.5 mm to 6 mm) to have the sleeve pressed in.

The problem that JGM ran into was that the bore spacing of the M5 only leaves about .200 of material between the bores with a siamesed bores. It would have to have a very thin sleeve with a D shaped hat on the top flange of the sleeve. Jim never got any money from Osh and had to wait for the sleeve company to decide if they could machine the unique sleeves. In the end, the sleeve company said it was not able to make a sleeve with such thin walls and D shaped top flanges.

The other problem is that one of your cylinder bores has some scoring (probably from heat) where the piston galled the unique plated surface. You will have to find a vendor that can refinish the bore and replate it or buy a replacement block.

Hopefully, you can have an engine assembled from the parts that you have.

Good Luck, John

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Last edited by jeeperjohn : 15th April 2004 at 22:43.
 
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