michaelmount123

Why do you want to replace the factory 968 valves? Are you simply going from the S2 37mm intakes to the larger 39mm 968 intake valves? Are you using the stock S2 camshafts? Sounds like where you are is a healthy ride that would provide lots of fun.

If it's time to refresh your head, I agree that the bigger intakes would provide a boost, but are your piston reliefs currently sized for the S2 valves?

bergerac

We just picked up a new 968 head from Porsche sans the valves. Second hand 16V parts are non existent here and we're not confident to use the first head we shipped over from the US for reasons I won't go into here. Rolling the dice on another used head sight unseen with the cost of shipping ATM was the less attractive option one you pay for a rebuild on top of that. The only sticking point in this plan has been the valves.

Porsche want AU$200/240 for intake/exhaust valves, Ferrea super Alloy exhaust valves are AU$170 and we've managed to source a 21-4N one piece intake valve for about AU$130. I'm not confident in using the cheap TRW after market valves in a turbo build.

The S2 motor is going into storage as a matching numbers spare just in case everything goes pear shaped. None of this probably makes financial sense to anyone in the US, but when you're only paying 25% more for new parts it's cheap insurance.

I've ordered Mahle pistons with reliefs to suit 968 valves.

333pg333

^^ Be interested to hear more about your build. Where abouts in Oz are you located and who is putting the motor together? Are you going for basically a turbo 968 16v motor or something a little more spicy?

bergerac

I'm in Perth, Its a bit of a father son project now that my father has wound his mechanical business down.

​​​​​​It's no were near as spicy as yours as we're trying to keep it streetable, probably similar to Sean's build with some overkill hopefully for reliability and not just destroying the budget.

My biggest concern ATM is breaking the transaxle, seriously considering going through the rigmarole for a 01E conversion, its not making the most pleasant sounds.

Feel free to PM me.

333pg333

Sounds like a nice build. Would love something like that for the street. You should reach out to Luke (aka 951turboRS) in these forums. He knows a thing or two and I'm pretty sure in Perth too.
I thought the 951 5 speed should be able to handle that power (without dropping the clutch at 5000rpm). I don't love the 6 speed to be honest. Preferred my old 5 speed which Sean swapped in the S2 r&p. But maybe too short gearing for you?

bergerac

Ive been in contact with Luke, he's been very helpful on my journey so far and only lives 15min away.

I'm starting with the S2 trans so hopefully it holds up, it sounds like it's full of marbles decelerating in second ATM so I'm a bit worried about it but maybe that's TT bearings. From what I understand the 083 F had some of the stronger AOR parts in it, maybe a freshen up and an OS Giken diff is a better way to spend the money.

333pg333

The S2 trans will be too weak and short geared for that motor. But if you don't try and break it, it might last a little while. I did see a guy in the UK making kits to fit one of the 01 boxes from VAG. Can't remember quite which one it is. Better option than the 6 speed from the 968 in my experience. Although a 5 speed turbo box is still a pretty decent option. I'll try and find that guy again. Saw him on one of the FB 944 pages.

944M3

My tranny whined like crazy when decelerating in lower gears, don’t know if that’s what you mean by “full of marbles”. If you haven’t already, try flushing it and filling with new transmission oil. I used Swepco 201, whining went completely away. I think any good gear oil would have worked though. I was actually looking into replacing the transmission it was so bad.

bergerac

Lobb is doing the kits,we didn't get that box here but they're cheap enough to warrant shipping. I'm following closely but the exchange rate isn't helping.. I've given up finding a 968 trans here and quotes to ship one from the US was more than the cost of the trans.

It would be interesting to know what the power limit is on the S2 R&P, the rest is basically the same as the turbo box.

333pg333

Is Lobb a company or shop in the UK? Perhaps it's the same guy I was looking for. I couldn't find it yet. But what I read seemed like a good deal. He would even source a used trans if required and they're cheap over there. Apparently there are some options for gearing and even straight cut. You might need to get some custom axles made. The 968 box requires uneven length. I think with your power it might be worth considering talking to the driveshaft shop in the US to get some made. Initially expensive but might be worth it. Having said that, some consider having weaker shafts and CVs as a form of 'fuse'.

I thought the gearing was shorter. Therefore smaller teeth could equal weaker metallurgically. I was also mixing up the r&p from the 'S' transmission which is definitely weaker than that from the S2.

bergerac

​​​​​​LOBB is a cpy/shop in the UK, kit includes custom mount/shifter/cables /axles shipped for around the price of a 968 trans plus associated parts . Not sure on the gearset/diff options yet but it's claimed they're more available.

Some PET diving shows S2 (AOS) ​​is the same as Turbo S (AOR) except for R&P(less teeth=weaker), 5th gear (academic for street, turbo is shorter) and diff housing/spider gears (irrelevant with aftermarket LSD). 3.85 final is probably too short for ~500whp. The plan was to use a semi-solid trans mount to avoid the binding of the CV's but the LOBB kit uses the earlier dual trans mount to help with this issue.