915 Side Cover Upgrade

[jamesjedi]

Hi, I am looking for some guidance. I have a magnesium 915 from a 3 L, that has been recently rebuilt and now has the retainer bearing. The box is all together.

What would be involved for me to upgrade the side cover?

[Matt Monson]

You would need to reset the backlash and bearing preload. You could use a later factory one from a 3.2 Carrera or the CMS or Wevo version with a larger more robust 930 bearing.

[356RS]

Wevo makes an aluminum HD side cover for the 915 gearbox. It's made to use the 930 differential bearing, larger OD than the standard diff bearing, so you will have to purchase the new bearing and then set up the side cover/differential bearing preload and check ring gear backlash.

[jamesjedi]

Thanks for the replies. Nothing is easy with these 915 upgrades. I do most of the work on my car. I would not where to start. Is it difficult? Special tools?

[Matt Monson]

Yes, special tools. It is one I would probably sub out to a shop because of the tools.

[gliding_serpent]

Unless you are racing, or putting in a hot engine or 3.6, or there is an issue... with a fresh rebuild of the tranny, i would leave well enough alone. The cost will add up fast. Maybe save it for routine synchro servicing.

[jamesjedi]

Thanks Matt.

And yes, I have a 3.6. Hopefully a vintage race, at least one.

[Steve@Rennsport]

Originally Posted by Matt Monson

Yes, special tools. It is one I would probably sub out to a shop because of the tools.

Absolutely!

This is NOT a DIY'er operation.

[gliding_serpent]

3.6 and racing... Do it. Good time to check your r+p, and if you also have a LSD, you may want to consiter a transmission cooling kit. (Sorry, i am on my phone so am not researching your build, just guessing here).

Matt is humble, but Guard also builds a side cover (one of his is enroute to me with other transmission reinforcement/upgrade goodies).

[Joe Bob]

Hope you put in the WEVO retaining plate.....

[jamesjedi]

Retaining plate is in. If I'd known what was involved in the side cover, I would've done that at the same time. The stuff is so expensive.

[Matt Monson]

Originally Posted by gliding_serpent

Matt is humble, but Guard also builds a side cover (one of his is enroute to me with other transmission reinforcement/upgrade goodies).

I appreciate the sentiment, but truth be told you got the last one that I'm probably going to make. We are refocusing on our gear and differential offerings these days and going to leave the sidecovers and shift gates to others. We will continue to offer the 1 piece (figure 8 or teddy bear) bearing plate. We were the first and still feel that we make the best one.

Regards,

Matt

[Matt Monson]

Originally Posted by jamesjedi

Retaining plate is in. If I'd known what was involved in the side cover, I would've done that at the same time. The stuff is so expensive.

What engine? How to you use your car? Maybe you don't really "need" one.

[jamesjedi]

964 3.6 w/rs cams, 993 intake/injectors and Steve Wong chip. I doubt that any big gains will be made. Some of the parts I had.
Mostly autocross and one day (hopefully) a race. It is the mag case 915 w/the 8:31 r and p. I have a feeling you're going to say I need it.

[Mahler9th]

I went through all of this years ago, with my hot rod 3.8L engine and 915 tranny combo. The Guard or Wevo retainer ( I bought the latter) are helpful I think, as is a stronger side cover.

Years ago I tried to do the backlash and preload on a 968 transmission-- I got pretty close before taking to a shop where my friend with experience did the work. Later I used the same approach with my 915. Took them partially disassembled. Pretty inexpensive to just pay for that work.

Many of our local racers with bigger motors (325-400 bhp from 3.6 to 4 liters) use mag 915's and almost no one uses a tranny cooler. Some of use use the Redline NS which is less slippery than their normal product. Others use Swepco. I use the former, and see no reason to change or install a cooler system.

When you deal with Matt and Wevo, you are dealing with the best. We are lucky to have them (disclosure... both have sponsored the Porsche Racing Club from time to time).

[gliding_serpent]

I agree on the trans cooling above. Most people do not run cars long enough to get to a critical temp. A lsd can add extra heat, but it takes time. Many say you need to be running over 20-30min to need a cooler.

I got one anyway. As my transmission is being rebuilt, I am plumbing in the return port to the lsd/r+p and then plugging it: Hottest, and most expensive part of the transmission. I also have a tranny temp sensor. If temps go high enough with my hpde use, i am installing the cooler and pump. If not, i save the weight. This way i do not need to dissassemble my trans later at $$$ cost and inconvenience should i need it.

Do it once, do it right is my motto. Or is it... Better more than less... Or maybe... A fool and his money soon part.

[KTL]

I have one if you decide you want to make the swap to the later side cover.

915 Diff Housing Cover- '84 Model Year

[Trackrash]

What year is the transmission? You said mag case from a 3L? The SCs had aluminum cases.

Post a shot of your trans.

That said, I put a Carrera side cover on my mag case 915. It's not rocket science, but unless you have special tools, and experience setting up a R&P, I would not recommend doing it yourself.

[jamesjedi]

915 is from a 3.0 Carrera. They were made from 76-77. They were mag and had the larger r and p.

[Steve@Rennsport]

Originally Posted by jamesjedi

964 3.6 w/rs cams, 993 intake/injectors and Steve Wong chip. I doubt that any big gains will be made. Some of the parts I had.
Mostly autocross and one day (hopefully) a race. It is the mag case 915 w/the 8:31 r and p. I have a feeling you're going to say I need it.

If you go racing, you WILL need a pump and cooler. These do not like running over 240 deg F.