Can a stock 951 block be bored and sleeved to 104mm? I have heard that the 951 stock block has somewhat thin cylinder wall and boring the block may lead to an unreliable engine?

Obviously, it is safer to bore a 3.0L block, but would be easier to just bore the stock block.

This scenerio is for a vehicle that will not see track duty.

What do you guys think?

 

I dont think so. I think the wall size is 10mm stock. The walls occasionally crack anyway, I think it would be nuts to take it down to 6mm.

 

http://users.wpi.edu/~mark944/deckedited.bmp

I took these measurements when considering making a sleever girdle to support the open deck. Looks like 9mm is the wall thickness at least in some places.

Edit- Just noticed that you said bored and sleeved Yes, I think that could be done, the iron will be much stronger. Especially if you get sleeves with thick walls that are "flattened on 2 sides" so that the walls are only thin where they need to be, if you know what i mean.

 

Search on 'MID sleeves'....I do 104mm all the time with lots of wall thickness.

Chris White

OK, not a member? (can't search) - https://rennlist.com/forums/showthre...eferrerid=1956

 

Chris,

How would the thinned, bored cylinder walls handle the heat transfer from the steel sleeves? Wouldn't this cause damage to the walls?

 

Take a peek at the MID thread – there is nothing left of the stock cylinder – it is completely replaced with a new ‘wet’sleeve.

As far as the older ‘dry’ sleeves – I am not wild about going to 104mm with those.

Chris White

 

Chris,

I have a damaged 2.5l turbo block at home which I considder to sleeve. In another thread I read that you were offering compete sets of parts and the labor to build a block. As I am from Europe, shipping might mean considderable cost so what about purchsing a package with pistons, sleeves... I have a good engine builder not too far away from where I live which would do the installation. I already spoke to him once about how they usually do the sleeves but they swear on truck sleeves to be used and they also keep them quite thin(2mm typicaly), nothing realy for high power. They have some experience with 944s too and I know about two customars racing them. In any case I would like to follow you reccomendations about the install because I think you did it already some times before. My plans are not fixed jet and currently I am finishing another car. Just let me know about your thought and give me an estimate about prices (PM would be OK too).

 

I can set you up with a parts only deal - keep in mind that the shop has to have a CNC machine to install these correctly, the old school boring macnine will not do a good job. The first set takes a lot of set up time. You also need a troque plate for the 944 to get the job done right.
I will PM you the pricing.

Chris

 

Thank for your help Chris!