Chaos

Any one have any experience sleeving a factory aluminum block with steel sleeves ?
Thanks

jerome951

Contact Chris White. He hangs out over on the 944 Turbo forum.
His home page is http://home.earthlink.net/~enhancement944/

I'm assuming you're talking about your S2.

macnewma

There are a few 951 guys that have done it. I don't think there is alot of R&D and significant testing, but there has been success.

There are a few different types of sleeves too. I think Chris White's method of using interlocking sleeves is pretty cool, but I am certainly not knowledgeable enough to give an informed opinion. I would talk to Chris as he is one of the nicest and most down to earth Porsche guys I have come across. He will definitely shoot straight with you.

Is this for the 944S2? Did you score a cylinder? Does anybody know the rules for rebuilding a motor for stock PCA racing? Can you use aftermarket sleeves or even oversized pistons?

Chaos

Looks like I have to find a new block. Walls are scored,any idea where I can find a used block ?
Thanks,
Gregg

macnewma

I assume you need to find a new block due to the rules, right? You could try 944Ecology as they seem to always have parts. You could also try Chris White or John at Vitesse. They sometimes have good blocks laying around. A post over on the 944 or 951 board might help.

Sorry to hear about your luck.

Bill L Seifert

I have a friend that did one on an 8v regular 944, and it worked great. The company that does it is Memphis Motorwerks, they are in Germantown, Tennessee, and do good work. I don't know their number.

I have another friend that has a 1989 944 Turbos S engine for sale. (27,000 miles) His email is Todandcharity@peoplepc.com

Bill Seifert

1987 944S Race Car

RedlineMan

Hey;

I don't think Chris has any spare blocks, and unfortunately he doesn't have much spare trime at the moment either**, but he has pretty extensive knowledge of the sleeving thing.

**I might have to go and steal his car and get it ready for him so we can even see him at the track this summer!!

Porsche Tech

I responded to another post in the 944 forums about this- steel sleeving is great and i have done that on many 944 racing engines however there is an alternative. Depending on how bad the scores are, it is possible to hone the scores out and you may still be within the tolerance group for your size piston. Once honed i have the Sunnen equipment to re-silicon impregnate the walls of your aluminum block. If the scores are pretty bad, bore the cyls to an oversize neccesary to remove the scoring, reimpreganate the block and there ARE custom pistons available now that can be used in the alucil bores w/ no problems gauranteed. If you want another mm or 2, more compression, no problem- the pistons are custom like JE et al. It is a totally functional and less expensive rout than steel sleeves and is esentially a factory fix. Steel sleves are the way to go if you want to spend the money

Porsche Tech

oops- ... steel sleves are the way to go if you want to spend the money but the fix i mentioned works well at a better price. I have both ways in 2 of my race cars and have not had problems with either. Seth.

Alan C.

The block is an aluminum/silicon alloy. Are you sure you are 'impregnating' the bores with silicon? My underestanding is that process is a light etching efffect to remove flowed aluminum from the silicon. I have made photomomicrographs of the bores in cross section. It is surprising to see how little silicon is exposed as a function of area fraction. It is also surprising to see the amount of micro porosity in the block.

Porsche Tech

Check in the factory repair manuals and you will see the process in the engine section 13-54. "machining cylinder bores"- requires 3 stone sets, roughing, dressing, polishing, felts set, Silicium mixture. The procedure is a factory repair. Shows the sunnen equipment and it is also the same process for the 928's and 1 model of older mercedes. I have done this many, many times. There are specific hones that must be used for the proper surface. The final step uses a felt lapping hone that you apply a special brown silicium paste to and also to the cylinder bore. You lap the paste into the aluminum. When you are done you have a perfectly impreganated bore. If you have ever seen a 944 block that has been honed you see the difference in colorand from the greyish finish of an untouched block. Trust me, it works great. I have been working on Porsche cars for 12 years and regardless of scoring, every stock engine i rebuild at least gets a very light hone and reimpregnate and i have had not one problem on any customer street cars some of which at this point have 100,000 miles on their rebuild. I have had no problems on any racing engines either. Just finished a 2.7 944 ITS engine w/ cross drilled crank, 968 baffle/pan and otherwise stock rebuild and it has 4 scca enduros w/ not a problem (nor leak for that matter)
The benefit of this process in conjunction with custom pistons specifically for use with silicium impregnated bores is that it is unneccesary to spend on steel sleeves/instalation.

Geo

Hmmm.....

Perhaps you don't realize that the crossdrilled crank is illegal in IT.

RedlineMan

You're such a damn kill-joy!!

Larry Herman

Yeah, but it's funny as hell when people accidently spill the beans, DOH!

Porsche Tech

Perhaps you just didn't read the post properly- (no flame intended), but i said cross drilled, not KNIFE EDGED. There is no weight change to the crank. It is strictly for improved oiling to the rod journals for durability issues. An additional oil hole is drilled in the rod journals along with eyebrowing the hole to allow for better oil flow out of the holes. There is NO performance benefit. The benefit lies in not throwing a rod through the engine block.