Carrier Bearing shims and diff - offset specs, Transmission: Differential Setup Options

[pcar916]

Hi Folks,
I'm setting up my 914-6 GT conversion with a new GT LSD and have two questions about the carrier bearing offset.
Here's the skinny...

1. I have the early 911 factory manuals instead of the 914 factory manuals so the ring is on the differential cover side instead of the drivers side.

2. Bearing preload is a simple affair if you have a good bearing-shim assortment and a way NOT to destroy the bearings as you put 'em on and off. Bearing shims are referred to as S1 and S2. Their combined thickness creates the bearing preload with the cover torqued down. Once that preload (S1 + S2= x mm) is known...

3. In the 911 manual, the ring offset is .1mm (~ .004 in) off-center TOWARD the diff-cover by installing a thinner S1 shim, and a thicker S2 shim.

4. In our 914's the ring is on the opposite (driver's) side from the diff-cover. Can someone with the factory manual confirm that the .1mm offset will be away from the differential cover and, for that matter, that it is still .1mm?

Pinion depth after that...

Thanks for the assist!
Ron

[charliew]

Sounds like you need a 914 manual. see if you can run down Matt Monson. He does porsche trannys in CO. He hangs out on the older nasioc suby forums and has a 914 and I think a 911.

[pcar916]

Thanks Charlie,
I ran into another thread on 914Club where Brad Roberts had kindly placed the factory 914 diff setup info a couple of years ago.

http://www.914club.com/bbs2/index.php?show...ion+depth+setup

That gave me what I needed for now... and the specs are both very different, and similar at the same time... for instance.

1. The ring offset is indeed always in the direction of the ring, regardless of where the cover is. So it's away from the cover in our 914's. That was predictable but it's nice to be confirmed.

2. The preload specs though are very different from the 901, and specific for SKF vs FAG bearings. Weirdly, the torque ranges don't overlap, so if you have mismatched bearings, you're on your own. Now do I assume that these days the manufacturing methods are so much better that it doesn't matter?

I don't know but I've just picked up another FAG to match the one I bought to replace the SKF I destroyed with a faulty puller. Hmmm, what to do with a single unused SKF bearing?

Otherwise the tools and procedure are the same.

Thanks again for the referral. I'll put it in my address book for another time.

Keep the shiny side up, Ron