ideola

Yes, I've searched. No, I have not found any definitive answer.

So, quick question: if one were to acquire a complete 1987 944S engine minus that lovely 16V head, what combination of cranks, rods, pistons, and 8V heads would yield a naturally aspirated high-compression (11:1-ish) stroker?

It seems like the S block has some advantages (girdle, auto-tensioner, etc.) over the earlier 2.5L blocks, but what I have not been able to determine from searching is:

• 3.0L crank will bolt into this block???
• Assuming I'm willing to punch out and sleeve, how large can I go on the bores with this specific block?
• What 8v head can I use?

Rods and pistons are no problem, as I have access to all kinds of aftermarket stuff, so I don't need to use OEM for those (although it would be nice if I could use OEM rods rather than custom).

Also, I don't care about anyone's opinion as to whether it would be worth it. That's for me to determine. So please don't go down that rat hole.

If this is a stupid question that has easy answers somewhere that I haven't been able to locate, please provide links, I'm plenty happy to read up.

Thanks all!

Arominus

Get a 16v head for it, it flows so much better than any of the 8v stuff. Seriously worth it. If you must go 8v just stuff the euro 10.6 pistons in it and your done in the short block. It's all the same as the rest of the late 2.5s. The magic of the S is all in the head. The 3.0 crank fits but I'm not sure about the rest of the combo to off stroke it off the top of my head.

Seriously get an S head, the S is 11 to 1 already and the head flows around 300cfm iirc vs the 160ish the 8v head does. It will stroke nicely.

ideola

Yeah, pretty much aware of that...any difference between the 16v head on the 2.5L 944S vs. 3.0L S2/968 heads? Or were they essentially the same. I have the entire intake setup.

Arominus

The 3.0l and 2.5 heads are different so they won't swap but otherwise the S head is very similar to the s2 head. The 968 has different ports, but the intakes do interchange between all 3 bolt pattern wise. Exhaust is the same pattern as well.

If you go with the S Stuff there should be a Maf kit coming out for it from rogue based on the stock intake setup. Be nice to the parts that bolt to the intake intake, the casting is magnesium.

V2Rocket

2.5L 16v head works on 2.5 block, 16v/8v blocks are the same.
3.0 16v head works on 2.7L and 3.0 blocks only.

To make one work on the other needs modification to the front coolant passage.

3.0 crank does go into the 2.5 block but you need to use special pistons with pin height raised to accomodate the stroke.

sleeving depends on dry or wet sleeves, dry appears to be OK to around 4.125", bigger than that and wet is a good idea.

lart951

2.5L 944S block is the same block as any late 944na or 951 block no differences, ideally for a turbo rebuilt the 944S block is my choice 99% of m44/40 blocks that i have seen have no scoring whatsoever.

pkt1213

928 motorsports can punch it out to 3.2L I think. Well not punch but install new cyl sleeves.

ideola

Cool, thanks for the answers guys, this brings a bit of clarity.

The trick seems to be finding a good 944S 16v head...they seem to be quite costly...you can probably guess why the setup I acquired is lacking the head in the first place.

Did the 944S have forged rods? If so, it would be interesting to take a 3.0 crank, use the forged rods (yeah, I know, some block work required), and custom pistons. Punch/sleeve the block to 104mm, maximizing stroke and displacement, with the least amount of custom (costly) parts.

Custom pistons are no issue whatsoever, as I do a ton of work with Diamond. So I can get whatever compression height I need...and, since I now have the OEM 16V slugs, providing samples isn't a problem.

If I do this build (a huge if!!!), I would probably skip right past Motronic (because I don't have any of the OEM harness or ECU components), and just go full blown stand alone engine management.

pkt1213

I dont think attaining 104mm is as easy and boring the block. I think they changed the block as to not thin the cyl walls.

odurandina

RL search engine was incredible a couple of years ago.

then, one day, up and stopped working. sucks.

V2Rocket

Have you seen the "hybrid stroker" stuff on the 944 turbo forum down below? Big displacement for not so big investment...check it out.

Voith

http://dundee.craigslist.co.uk/ptd/4287201473.html

This looks very nice.. Complete set for the price of rods.

Arominus

They do suffer from tensioner failure if the pads don't get changed, it happens to all of the 16v's. The rods are the same as the NA and I believe the Turbo for that year as well.

Cyberpunky

Just use google to do the search on and it finds the answer on RL anyway. Works heaps better than RL search

william_b_noble

when I had to part out the 944S I had been carefully restoring, the head brought about $1000 (recently rebuilt), the rest of the block brought either $50 or $100, I don't remember which.

the car had noticeably more power than an NA, but I don't know that the added complexity of the engine is worth the effort.