Ian Carr

Alright any one who has not read previous post my motor was not running right and we found out that it was really bad so we took it out and sent it to a local shop(the cylinder wall in cylinders 3 and 4 were scored pretty bad).

WELL it seems now that after a month or more now our mechnic figured out that you can not bore out a 951 cylinder wall to far because of the special coating on the cylinder wall. SO now he he going to sleave the cylinders and use the stock pistons and get new rings . Also to add to this, he is going to balance the crank, piston rods and pistons. Does that mean he is is just going to equal the wieght of the pistons and connecting rods on all of the cylinders? I know what is done to get the crank balanced though. (thank you two guys garage )

Along with that he is putting new guides ext.. in the head and refinishing the face. New bearings in the crank and on the balance shafts. New water pump. New belts.

Hopefuly this is only going to take a couple weeks now I really want to get my car back on the road.

-Ian

hosrom_951

Regarding the cylinder walls, i know people that bored all the way to 104mm on the stock 2.5 block without problems. Maybe it is the honing process that he is worried about? that requires some 'special' treatment after boring.

What sleeves are you getting (if you don't mind me asking), if you were told that you would sleeve the block BEFORE you ordered the JE pistons, then you may have sleeved a 2.7 with matching JE pistons

NZ951

Why not make a 2.7 or 2.8???

hosrom_951

Andy, your quick

NZ951

You must have beat me by seconds... lol

How much are JE pistons these days? 1K?

hosrom_951

Actually Ian (TurboX) got a set of JE 100.5mm aluminum pistons (with rings) for $600, mine go for that price (OEM) but i don't have the overside for turbo models.

Tom M'Guinn

At the risk of being a wet blanket, keep in mind that the machine shop needs to know what it's doing for the sleeves to work out right. On the 951, sleeves have been known to sink, shift, etc. when not done right. (Not always of course, but some builder seem to have better luck than others.) If the shop is not familiar enough with the 944 block to bore and hone the alusil bores, you may want to make sure they have the experience to sleeve it and/or make sure that he warranties the motor. Sleeves are often used to increase the size of the motor. If you are staying at stock size, you may find that a good used block is cheaper than installing sleeves -- without the risk of a bad sleeve job. Just food for thought.

NZ951

Do you not always need to sleeve when going to a 2.8?

hosrom_951

104mm bore makes 2.7L (3.0L with the 3.0Lcrank)

100mm bore makes 2.8L with the 3.0L crank (2.5L with the 2.5 crank which is stock obviously)

106mm bore makes 2.8L (3.1L with the 3.0l cank)


The max recommened si 104mm in the stock block, going over that is where people go for sleeves (do a search on this).

Bengt Sweden

I just want to support Tom's recommendation. Get a new mechanic who is experienced with 944s. To me this smells bad job at a high price.
bngt

DAR951

Smells that way to me too...

Aluminum-Silicon blocks aren't (or at least shouldn't be) a mystery. They have been around for decades not only in Porsches and BMWs but in US drag racing too! Likewise the Sunnen CK-10 is (or again, should be) well known to performance engine builders.

If your mechanic/engine builder is just "discovering" either of these things... run like the wind...

Here's a link to a pretty good basic primer on the various approaches to using aluminum for engine blocks (doesn't address re-building, but it's a good place to start if you want to know more about Alusil, Nikasil, sleeves, etc.)

http://www.findarticles.com/p/articl...il/ai_54620821

Ian Carr

This mechanic was sudgested by our porsche racing friend/mechanic cause of his great work he did to his 911 and 944's. We arn't looking to bore it out (trying to keep prices as low as we can) The JE pistons only go for 600 for pistons rings and pins . Sleving the motor is going to be much cheeper than boring it out and getting new pistons. We need to call the mechanic again today cause if he got the JE pistons already then he should get sleves that our 100.5. Ill keep you all informed.

Hosrom I talked to you before about pistons you just didn't have any for the turbo model

-Ian

badass951

I did not want to mention it at first, as TurboX was so excited and I did not want to spoil the fun, but I agree with all of you. Find a new shop or make sure he does his research this time. It should have been obvious right away that the block had an alusil coating and that the same procedures to boring or honing are not applied.

macnewma

I agree with the previous guys. If I were you, I would either just find a good short block or sleeve it out to a 2.7-2.8L. The cost shouldn't be any higher and the extra displacement would be great. I would change the JE order to oversize pistons if you can.

Also, did your machine shop just go ahead and bore the cylinders and then realize they screwed them up? If so, I would guess he has very little 944 experience. It is pretty common knowledge that Porsches and BMWs use Alusil or Nikasil.

Max

Ian Carr

He did know that it had the alusil he was not sure how much you can bore out of it. The reason we are not getting over sized sleeves is so we do not have to buy new pistons. This mechanic has made over 10 951 race motors im sure he knows what he is doing...

also no he did not bore it out yet