My '81SC Engine Rebuild with Trophy Performance Las Vegas

[charlie.tango]

Hi All,

Late December 2020 I purchased a '81 911SC. I've originally purchased it since it was in running order with the PPI and no/minimal rust.

It definitely needed a tranny rebuild and a engine rebuild. I originally had an idea of working on the car myself but my wife talked sense to me that it would be quicker to have a shop work on it. Since I live in Las Vegas, there were not many shops from my searches. All l can seem to find where Carl's and Trophy Performance. After thinking it over and from what info I could find online, I've decided to go with Trophy Performance.

When I reached out to Todd about a tranny and engine build and he suggested I visit his shop. His shop is a great facility. It made me feel at ease knowing that my Porsche will be in good hands.

Unfortunately, Todd is somewhat backed up with the current projects and his team estimated that it would take about 3-4 months. I was ok with that since it will give me time to also prep for me to get ready to paint my Porsche in the fall. No way was I going to try to paint in the summer in my garage

Looking forward to sharing my experience with Trophy Performance and their work since they don't appear much on this forum compared to the ones in Cali.

[winders]

Take the transmission to Bill Rader at Bill Rader Motorsports. He is the best in the business and reasonable.

6963 Speedway Blvd Unit 108
Las Vegas, NV 89115

[charlie.tango]

Thanks, I'll contact them for more info!

Originally Posted by winders

Take the transmission to Bill Rader at Bill Rader Motorsports. He is the best in the business and reasonable.

6963 Speedway Blvd Unit 108
Las Vegas, NV 89115

[Glenfield]

Nice looking car there! Deserves a great engine and great tranny. You should post on the technical board and ask for recommendations of shops to do the work. Not saying Trophy isn’t that, but you should take all reasonable steps to ensure that you’re in the best possible hands and that’s an easy get.

Are you going to rebuild in stock? Bunch of stuff to think about when you do:
- people have had issues with main and intermediate shaft bearings from Glyco. May be worth spending up for Clevite and OEM
- Have a machine shop component balance the crank, rods, piston assemblies to 1g ... strictly not necessary for a stock 3.0 as they’re pretty well balanced out of the factory, but also not expensive and it’s good dinner table convo
- ARP rod bolts: again, not necessary but since you’ve balanced the engine ... See how that happens? Does give you a bit of extra insurance and maybe you do a hotter top end in the future
- Replace your head studs with steel (or Supertec etc)
- No need to buy new P&Cs if they’re out of spec. Can have them replated and just get new pistons
- A hotter cam is a nice upgrade for SCs. You’ve got a small port car which goes well with 20/21 but I’d be really tempted to check out the M1 cam William Knight is making

Hope that helps. Best of luck with it and post around here for advice.

[charlie.tango]

Thanks Glenfield! I've had several discussions with Todd. The previous owner has done some of the mods that I was doing to do: front fender oil radiator, oil fed cam tensioner, and the pop valve for the airbox.

Since I was going to get the engine rebuilt I didn't want to bother with stock specs. I plan on:
1) Change out or regrind the cams to a 964 profile. I believe that will be similar to the 20/21 you've mentioned below.
2) Run at a higher compression. From my discussions we're aiming to see about a 10.x range ratio. They've also mentioned about increasing it from a 3.0 to 3.2

Originally Posted by Glenfield

Nice looking car there! Deserves a great engine and great tranny. You should post on the technical board and ask for recommendations of shops to do the work. Not saying Trophy isn’t that, but you should take all reasonable steps to ensure that you’re in the best possible hands and that’s an easy get.

Are you going to rebuild in stock? Bunch of stuff to think about when you do:
- people have had issues with main and intermediate shaft bearings from Glyco. May be worth spending up for Clevite and OEM
- Have a machine shop component balance the crank, rods, piston assemblies to 1g ... strictly not necessary for a stock 3.0 as they’re pretty well balanced out of the factory, but also not expensive and it’s good dinner table convo
- ARP rod bolts: again, not necessary but since you’ve balanced the engine ... See how that happens? Does give you a bit of extra insurance and maybe you do a hotter top end in the future
- Replace your head studs with steel (or Supertec etc)
- No need to buy new P&Cs if they’re out of spec. Can have them replated and just get new pistons
- A hotter cam is a nice upgrade for SCs. You’ve got a small port car which goes well with 20/21 but I’d be really tempted to check out the M1 cam William Knight is making

Hope that helps. Best of luck with it and post around here for advice.

[Glenfield]

Now you’re talking! Hold off on the cam choice until you’ve made a call on your compression and displacement and, importantly, induction. The 964 is a known bolt-on to SCs and 3.2s, but if you’re changing other parts you may get more out of the engine with systematic thinking. You’ve got a small port US SC motor (by the looks of your bumper guards), so no amount of cam will overcome the fact that the engine will be out of breath by ~6000 or so RPM. You might do well to have your heads ported slightly (again, systematic). I didn’t do any porting (should have), and so I chose a 20/21 cam which works will with the port velocity of a small port SC for midrange torque. The combination works very well up to 6000 rpm (which is a bit of a tease if I’m being honest). Here’s some good reading on the subject: http://forums.pelicanparts.com/porsche-911-technical-forum/163860-best-cam-profile-stock-sc-3.html.

Will let others chime in on bumping compression. Above 9.5:1 and consensus starts to be that you ought to twin plug your heads. I think it’s probably a more complex answer and depends on cam, timing, altitude and temperatures. The gains from compression are relatively marginal vs displacement though and so take the opportunity to up that to a 3.2SS. Makes porting heads even more important though since that’s a rev happy setup.

I’m indulging my own interest here by posting but you really ought to give William Knight a call (bc he’s sick for this stuff and will give you a lot of time). Henry was also very helpful and generous with his time when I went through this. He helped salvage a bad situation on my engine rebuild.

[Glenfield]

Sorry, one more thing. If you’re doing your transmission anyway, match the gearing to your engine and intended use.