Voith

I need a single 104.x mm 16V used piston or alternatively a correct technical drawing of 3.0 16V piston or 3.0 turbo piston.

Must convert my 8v piston dish to 16v and need correct valve reliefs positions and measurements.

RajDatta

I have a set of 4 with 3 useable ones. I will make it worth your while for all 4. Let me know.

Voith

Would you sell just the non useable one? I just need basic measurements..

sherry66

Hi, I have an old one here you can have for free. If you can give me your address I will post it to you from uk. Also have 968 piston machined to 8.5:1 for 2.7 8 valve turbo head I can post but would need that returned.

sherry66

Hi Voith, forgot to say if you look at the 'S2 repair' thread on TIPEC uk , you will see where I have cut valve reliefs into JE 8v turbo pistons for 16 valve head.

333pg333

Wouldn't it also be dependent on what size valves you intend using?

Voith

PM sent.

I have new 104.5 8v turbo pistons and need to machine the crown to 16V 968 head.

Every machinist I approach wants something to work off (naturally) and since I dont want to over complicate, single stock pistons would be perfect for measuring valve cutouts. The D shaped dish will just be modified to O shape in the lathe.

Thanks.

What matters is the center and depth, diameter can be modified.

I will use stock 968 intakes though so stock placement and size should suffice.

blade7

On a wossner drawing I have it seems the bowl in the piston crown is a different shape on the 16v turbo piston, it's not just about valve cut outs.

Voith

Can you post it please? Im not concerned about bowl shape, I just want to make sure valves wont hit the piston. I'll machine piston to look much like HMR 968 turbo piston.

blade7

I think it may be the intellectual property of the dealer Wossner supplied it to so not sure that I can post it on the net. I may be wrong but the 8v piston bowl looks deeper, removing more material to make it the shape of a 16v bowl seems like it would drop the comp ratio further, which seems the wrong thing to do when one of the benefits of going 16v is the potential to run higher comp before the onset of knock.

sherry66

The 16v head chamber is not as big as the 8v so raising compression ratio. With the valve relief cut into the 8v turbo pistons ratio should be around 9:1

blade7

What about the squish using an 8V bowl with a 16v head ?

Voith

I am shooting for 8.0:1.

Left is my 8v Andial/Mahle piston, right is HMR 16V T piston. I want to get exact positions for those two cutouts. One bowl shape is as good as another.

sherry66

Hi Voith, hopefully there should be a couple of photos showing the 968 piston I had machined for 8 valve and je 8 valve turbo piston machined for 16v turbo in the centre of s2 piston and another je piston.
Anyway good luck on your build and I will send out piston Monday.

Voith

Thank you much. On what machine did you do that?

Btw: Ive look in your thread on tipec and first half of pictures are not working. Impressive project though.