Ken D

Yes, the question is are you using bore-in cylinders or slip fit?

Sire

maybe noob question but is the differnce between bore in or slip fit?

eddieb4

New 3.8 pistons and 3.8 jugs so no boring and no sleeves ... at least as I understand it.

mooty

tell tim, i said hi
he's a good guy and knows his stuff

HiWind

Good luck with this - will be amazing!
Are those Mahle barrels and JE pistons?

Juha G

Slip-in = the cylinders "slip" into the engine case. Cylinder bottom sealing is done between the flanges. (this is as original street engines).

Bore-in = Engine case needs to be machined (borred) to fit the cylinders. Sealing by O-rings which requires further machining of the case for the O-ring grooves. Sealing between the flanges is not possible because there is just not enough surface area on the flange for proper seal after machining.

The original case has cylinder openings for the 3.6 cylinders. The 3.8 cylinders are bigger in diameter so you can either have same outer diameter (=slip in) with thinner cylinder walls or original thicker cylinder walls which require enlargening the case openings (=bore in).

All the racing engines had the thicker cylinder walls. I think any of the top end engine builders will advice to go with the thicker cylinder walls. It will cost more because of the machining work needed but it is the right way to do it.
Both slip in and bore in cylinders are available for the engines.

I went with the Mahle "bore in" / Motorsport cylinders in my "RSR" build. Here are some photos: https://m3supercar.1g.fi/kuvat/993RSR/Winter16/

mwneedham

That car will be a beast.
Just picked up a 3.8 conversion with many of the same mods. Very fast and fun car. With the 5 speed active trans, still getting used to taking turn 7 at Sebring in 1st gear! Good luck with the build.

eddieb4

Thanks for the education. Apparently I needed it. They are Mahle slip in .... this car will not be a race car but it will see a track from time to time.

911Jetta

Awesome post! Thank you for the detailed info.

Pics please!

What about keeping it a 3.6 and improving everything else? It seems like there are bigger gains keeping it 3.6 (if you don't need new pistons/cylinders?), and changing the cam and adding an improved engine management system (Motec)....

Like this:

eddieb4

The base head gaskets we're leaking like a sieve so the pistons and jugs needed to be replaced anyway. In order to add gaskets they needed to be changed even if they didn't leak. The cams are being custom ground to optimize horsepower and torque.

That looks like a beautiful setup. I'm hoping that the figures will be close to what you stated but probably will be more like 280 to the wheels.

Spyerx

Oh yeah MSI is still in business. Super cool guys there, they supply all the nascar, and lots of the pirelli cup etc not running center locks.

http://www.msiracingproducts.com

I just called them and ordered. They have a new website looks like the link I had in my thread broke.

Will watch your engine build. This is the next step in mine once I finish the safety/etc. Debating trans build. That's easy enough to do last though, as I like the gearing, but may want a longer 2nd and then fix spacing of 2-3-4, keep 5th as a cruise gear. On track 2nd is just a little short. But trans is very use / motor dependent.

I'm really not wanting to paint my car. Its in pretty good shape. As if I paint it, I won't want to drive it. Sunroof stays. It is a street car!!!

OlsenMotorsports

Cannot wait to get this car back from paint and get started on it!

You can follow along also with picture updates here at facebook.com/olsenmotorsports


-T.O.

eddieb4

Car is a rust free California car that had wood laminate interior trim (ugly), torn seats, dirty linen carpet, lots of minor paintwork and faded paint from the California sun.

C4inLA

Are the engine pics before and after teardown?

eddieb4

Teardown ... case just cleaned up a bit and not assembled.