kont5u

Hi guys. I've been following this forum for a while since I bought my first Porsche last summer. The car is a -87 944 Turbo with some modest modifications such as 996 GT3/Turbo brakes, Wiechers Sport roll cage, Leda suspension with H&R springs, KMS MD35 engine management, retrofitted OEM LSD and some exterior modifications. At first my plans were to drive the car and enjoy the ride while trying to learn somenthing. But as a minor oil leak further developed at a dyno session I decided to pick the whole engine out at least for the winter season.

The car was rumoured to make some 370 BHP with the KKK turbocharger it was equipped with. On my dyno session it produced 338 BHP/420 Nm while having some grip issues. However I never found out how much boost it was running on.

So I wanted to build a reliable engine with enough HP for some track driving without being overtaken by too many 911's out there. I thought that by increasing the displacement with a S2/968 crankshaft would get the car more HP and make it more driveable on the street as well. But then I found a complete S2 long block for a reasonable price so I bought it. Now I have both the 2.5 L 8V turbo and the 3.0 L 16V engines taken apart. Using the more stable S2 block with the better flowing 16V head seems to be the way to go but the block definitely need to be sleeved. I have understood that dry sleeves is a fair choice but Darton MIDs would be better. I already ordered a set of 800-400 MIDs for the 3.0 L engine, but the order was canceled by the retailer because of prolonged delivery they said. I think I would go with dry sleeves, but as Darton doesn't recommend using dry sleeves I don't have the dimensions needed for manufacturing suitable sleeves.

I know a lot of dry sleeved 2.5 L and 3.0 L blocks have succesfully been made, so if anyone has any drawings or dimensions to help out with, I would be very grateful. Any thoughts about a preferable approach to this project are also more than welcome. Off-set grinding either of the crankshafts also seems an option to consider. Anyway, I hope I get some valuable advices to get the project forward and post some updates along the process

lart951

Get a hold of Chris White on this board he is the GUY to go if you want a 3L 16V turbo
http://www.944enhancement.com/

chris@944enhancement.com

blade7

Duke is nearer.

rbuit

Why not go the alusil way with mahle pistons.
what power do you want.
Here in the netherlands is a company who has experience with the darton's, if you are interested.

KSira

Interesting topic, I am also drysleeving my S2 engine. Why would Darton not recommend dry sleeving?

kont5u

I have noticed Chris is the right person to talk to. But I prefer making a topic on this rather than contacting experts privately as I suppose there are a lot of other 944 owners having same kind of questions. I'm a type of a guy who wants to learn and know what is done to my engine and why. I prefer doing things myself rather than handing the engine over to someone else to rebuild it, even if it would take more time.

First I thought about going with alusil cylinders and maybe Wössner pistons. But there are a couple of reasons why I changed my mind. Two of the cylinder walls on my S2 engine are scored rather badly, so it propably would at least need to be bored to oversize. To get alusil cylinders machined and finished the correct way is not cheap at all, not to mention the limited availability of pistons etc. Going the iron sleeve way seem to have many benefits. There are at least some 2.5 L engines in Finland that have Darton MID sleeves, so finding the right shop here to do this should not be a problem.

I read about what happened to your engine KSira, seems like a nightmare to me. I hope you are getting things right.

Maybe I misunderstood them as I was asking a bunch of questions about their "blank sleeves". They said that they don't have off the shelf dry sleeves that would fit the 944 3.0 L block and that the wall thickness of the alusil block would be too thin to support the sleeve. Perhaps they meant for their off the shelf sleeves. Anyway I believe they would make sleeves that would fit 944 3.0 L block if someone provided them the dimensions. I found that at least Rolls Royce cromoly sleeves have been used on these blocks. But if it pays off to dry sleeve the block, I still think I would need some preferred dimensions. Or maybe I could just walk to the machine shop and ask their opinion. Do you already have your sleeves ordered KSira?

KSira

The sleeves are not ordered yet. I have someone lined up to do the dry sleeves for me. He wanted to use sleeves made for the chevy V8 with alu cylinders, if I understood him correctly. He also advised med to keep the diameter down to stock, or as small as possible, to keep the wall thickens.

blown 944

Try looking here: http://www.lasleeve.com/technical

kont5u

Sorry I forgot to mention, 400-450 BHP is what I'm expecting to start with. Reliably to handle the punishment on occational track days.

Thanks Sid! That company seem to have sleeves for the 2.5 L engine. I presume with some help from them I could figure out the dimensions needed for the 3.0 L. I guess the cylinders for both engines are the same length? Anyway I could go and measure it once I get to my carage.

blown 944

They will have the correct length. Just be sure that they machine the cylinder all the way down. Otherwise, you will need to remove the remaining aluminum. If you don't the pistons will gall. I think this may have been a common problem with the early sleeve installs.

kont5u

So there will be no aluminium below the new iron sleeves in the block to support the sleeves? The only element supporting the sleeves from moving downwards will then be the flange on top of the newly installed sleeve?

blown 944

No, there will be in the crank cradle still.

968tcab

89 s2 darton dry sleeved block ready to go. Let me know if interested? block, cradle, arp head studs, balance shaft,covers etc.

Mike

kont5u

Too bad I already have bought a complete S2 engine. Anyway I think I would prefer starting with an untouched engine, in addition shipping it to Finland would cost some money too. But depending on the price I could think about it

Chris White

I do have a set of 3.0 MID sleeves sitting on the shelf....