964 cylinder on 930

[Pesch]

Hello folks,

Starting to make plan for the rebuilt of my 930 engine but been infected by the "while you're at it" disease...

Among other modifications, I'm willing to increase displacement.
For that matter I'm checking few options on the bore side of the equation (stroke may be also modified by GT3 crank).
- Mahle 98mm P&C
- Nickies
- 964 early cylinders machined to fit 930 stud spacing (and spigot)

Does anybody ever did the 964 cylinder modification or heard about it?

Thanks

[JakobM]

I think it should be possible to mill/drill such oval holes by a machine shop. I beleive those are some type of mahle cylinders but not sure

[Tippy]

Oooh, that's some end mill deflection to mill that deep. Good things it's aluminum

[Pesch]

Thanks for the picture, looks like it's been done...
I'm thinking of using early style cylinder to avoid to interfere with the sealing.

Trying to figure out how to machine the holes at the moment... tiny boring bar in lathe, broaching, EDM...

[JJK78-951]

Originally Posted by Pesch

Thanks for the picture, looks like it's been done...
I'm thinking of using early style cylinder to avoid to interfere with the sealing.

Trying to figure out how to machine the holes at the moment... tiny boring bar in lathe, broaching, EDM...

If you are machining them to fit it does not matter which cylinders you use early vs. late.
$.02
J

[turbo nut]

Also need a spacer on the bottom of the cylinder.

[TurboKraft]

Not saying it hasn't been done before, but that doesn't look like a good idea to me. You're milling into the cylinder to tighten up the bolt pattern, and reducing the cylinder wall thickness -- on a boosted engine.

Just buy the correct 98mm slip in cylinders and be done, make your life easy.

If you want to stroke the engine with a GT3 crank, that introduces a whole other level of complexity because now you're adding rods and custom pistons with a revised wrist pin height.
We build a lot of these, give a call or PM to discuss.