Porsche Enthusiasts Club Forum

Just something I've been toying with since I need a new engine for my S.

What are the differences between the 8v and 16v engines below the head? From what I can tell looking at the parts PDF files there isn't a great deal other than ancillaries. I heard the sump was a different capacity but can't find any proof to back this up, con rods seem to be the same but unsure about the pistons.

Since my head should (cross fingers) be pretty healthy and full S engines are currently more than I'm willing to pay for a car that's starting to resemble a sieve in places and 8v engines are freely available and so cheap I thought I'd look into this but drew a bit of a blank.

If you want to fit the 16v head to the 8v block it won't fit. I was interested in doing it the other way around as I have a rebuilt 2.5 8v short engine.
http://cgi.ebay.co.uk/PORSCHE-944S-2-5-16v-ENGINE-Ventiler-TESTED-PERFECT-/270614721739?cmd=ViewItem&pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3f01e4f4cb
Not too bad pricewise. By the time you fitted belts & rollers & seals etc will be 1K but if it's worth doing do it right.

Yeah I've had my eye on that engine for quite a while now. At that price I'm not too interested for now as I'd rather get my 8v going then concentrate on the S after that.

To the best of my knowledge/experience, there are only two blocks: the 2.5 and the 2.7.

2.5 = 924S, 944, 944S & 951
2.7 = 944 2.7, 944S2 & 968 (+968 Turbo)

It is going to be a suck it and see excercise.

Unless you know someone who has done it.

Edited to say, PET says " Part Number Unknown ".

Pistons would be different, 8 valve engines have flat topped pistons with 2 valve recesses and 16v have 4. But I suppose you could swap them assuming the 16v pistons you have are ok.

I've been running a 16v bottom end with an 8 valve head although a 3L, You can do it that way round without changing pistons but not the other way.

Thanks for the info. I guess the first thing to do is take the engine apart and see what I can rescue. Still debating whether the car is worth rescuing at all for now but it'll have to wait until the other car is finished.

Tried to persuade Porscheapart to sell me a 16v head for mine. They were adamant that it didn't fit. Maybe they meant you had to change the pistons as well.

Pistons are the obvious thing, not sure of belts as some of the S lump was research for the S2 3 litre lump. Alternatively you could make me an offer for the S2 lump in the garage

For an S2 conversion what else would be needed to work? This is just to feed my thirst for geeky car knowledge more than anything. Last time I checked S2 engines went for a lot more than S ones unless you're willing to accept my kind offer of £150 and a bag of sweets?

Ok, 2 bags of sweets.

Would need an S2 ECU & engine loom & AFM. Probably some other odds & sods as well. Looking for around 800 for the engine.

You don't need any of that. Just a remap. Thats cheaper & will get it spot on. The water pump gaskets seals belts & rollers will be almost 1K. So 800s a lot! Using the 8v head solves the manifolds. These days you could just go out & but an S2 But then again if your mad enough.

edit: If the S2 engine is complete with head & cams then thats a good price. Was thinking it was a short engine for some reason. ( )

I bought a complete S2 recently as I needed an engine for my project, stripped the car & sold all the parts I don't need, it worked out financially. I think 800 is reasonable for a decent lump but you'd still want to do belts, seals, clutch etc (which is where I am with my project).