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964 C2 3.8 Build Thread

Old 03-09-2017, 03:34 PM
  #16  
Ken D
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Originally Posted by eddieb4
Is question related to 3.8? If so, new Jugs and Pistons.
Yes, the question is are you using bore-in cylinders or slip fit?
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Old 03-09-2017, 04:23 PM
  #17  
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maybe noob question but is the differnce between bore in or slip fit?
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Old 03-09-2017, 05:20 PM
  #18  
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New 3.8 pistons and 3.8 jugs so no boring and no sleeves ... at least as I understand it.
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Old 03-10-2017, 03:14 AM
  #19  
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Originally Posted by eddieb4 View Post
Spyerx,
Holy cow! You've done an amazing job on your ride. Luckily I've got Tim Olsen from Olsen Motorsports doing up the suspension and braking on mine and he is a master and a great guy to boot!
I'll ask him to check out your thread ... I think he probably has already.
Thanks for the input and I will be reaching out to you in the coming weeks / months if you don't mind. Actually interested in your wheel studs but link doesn't work anymore. Is that company still in business?
Thx
tell tim, i said hi
he's a good guy and knows his stuff
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Old 03-10-2017, 05:29 AM
  #20  
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Originally Posted by eddieb4 View Post
New 3.8 pistons and 3.8 jugs so no boring and no sleeves ... at least as I understand it.
Good luck with this - will be amazing!
Are those Mahle barrels and JE pistons?
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Old 03-10-2017, 07:55 AM
  #21  
Juha G
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Originally Posted by Sire View Post
maybe noob question but is the differnce between bore in or slip fit?
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/

Last edited by Juha G; 03-10-2017 at 10:29 AM.
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Old 03-10-2017, 09:05 AM
  #22  
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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.
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Old 03-10-2017, 10:00 AM
  #23  
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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.
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Old 03-10-2017, 11:27 AM
  #24  
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Originally Posted by Juha G View Post
Slip-in = the cylinders "slip" into the engine case...
Bore-in = Engine case needs to be machined (borred) to fit the cylinders...
Awesome post! Thank you for the detailed info.

Originally Posted by mwneedham View Post
That car will be a beast.
Just picked up a 3.8 conversion with many of the same mods...
Pics please!

Originally Posted by eddieb4 View Post
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.
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:
Rothsport Racing: These engines have stock pistons and heads but with a custom camshaft designed for very broad torque. They make 325 hp and feature Motec and Rothsport EFI.
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Old 03-10-2017, 12:50 PM
  #25  
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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.
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Old 03-10-2017, 01:01 PM
  #26  
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Originally Posted by eddieb4 View Post
Spyerx,
Holy cow! You've done an amazing job on your ride. Luckily I've got Tim Olsen from Olsen Motorsports doing up the suspension and braking on mine and he is a master and a great guy to boot!
I'll ask him to check out your thread ... I think he probably has already.
Thanks for the input and I will be reaching out to you in the coming weeks / months if you don't mind. Actually interested in your wheel studs but link doesn't work anymore. Is that company still in business?
Thx
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!!!
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Old 03-11-2017, 10:33 AM
  #27  
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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

https://www.facebook.com/OlsenMotorsports/
-T.O.
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Old 03-11-2017, 10:49 AM
  #28  
eddieb4
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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.
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Old 03-11-2017, 12:49 PM
  #29  
C4inLA
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Are the engine pics before and after teardown?
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Old 03-11-2017, 04:36 PM
  #30  
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Originally Posted by C4inLA View Post
Are the engine pics before and after teardown?
Teardown ... case just cleaned up a bit and not assembled.
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