I need to know the thicknesses of the paper seals/spacers so I can reset my r&p depth.

Had to combine some pieces to get a good tranny... and add the H gear 5th

Thanks, Chris

0.1mm, 0.15mm, and 0.2mm are the thicknesses of the available ones. Measure your old ones to see what you have.

--DD

Thanks Dave. The old ones are long gone. There are parts to the story I intentionally left out

Do a "prussian blue" test, or if you dont have some machinists dye around, use some white grease.. put a nice but not to thick coat on the ring gear.. assemble the tranny with whatever gasket you have..put the tranny in gear, rotate the input shaft so everything is turning in the forward direction...

the pull the diff out, check the "smear" on the ring gear teeth.... if the white grease has a wear pattern halfway up, and halfway down, just go with it...if the wear or wipe is to high on the ring gear use a thicker shim..

Most of our cars dont make enough power to be really to concerned about perfect r/p depth...if we dont get it right we just hear a bit more whine from the tranny..


unlike my friends 3.8 twin turbo which shears teeth off a G50/50 ring gear

I beg to differ...

At the time, like a decade ago , I didn't know the paper was a spacer, so a simple syncro replacement became this in 2 months. Carbed 2.0L and sticky 205's.

Since I have 200hp -6 with ~300 turbo'd in its future I NEED to do it right.

The story I was going to skip... the internals from a tailshifter with changed gears is going into the sideshifter case. They had a different number of steel shims/thicknesses on the shaft so to save some time I am going to use a few feelers of the correct thickness instead of the fragile paper to get spacing right between everything, then have Brad send me just the paper piece I need.

Thanks for the info

Chris

Im putting about 275hp through my 901...

All Im telling you is you can "backwards engineer" the proper gasket thickness

Ive rebuilt the tranny the "Porsche" way a few times..... yet I still check the wipe pattern on the diff

What you want is a proper marriage of the ring and pinion.... you can measure, shim, add, do arithmetic.... etc..all that dont count for a pile of dog doo...

unless the "wipe" between the ring and pinion looks ok...

I swap gears or whatever I need to do... bolt it all back together and check the wear on the r/p... this can tell you if you need to use a gasket on the diff cover or not use one, or if you need to increase or decrease the intermediate gaskets thickness, or if you need to adjust the shims on the gearstack...


Some of Porsches procedures are draconian.. like cam timing on a 911, You can get the needed result in a much neater fashion...

think "outside" the box or should I say factory manual?

If you are going to try and run 300 hp through a 901 you better do more than set the pinon depth. You need a bigger intermediate plate and to set the Differental over preload at its maximum.

Ken

factory manual?? wait, I take that back, I think I do have a copy somewhere.

I was trying not to write this much...

Tim, I shoulda said "I need the right results" sorry for the confusion.

The "wipe" method is the basis for my procedure... but sliding feelers in instead of swapping gaskets. I spent alot of time looking for ways to make this simple for me
I was originally looking for someone to do it for me because of the previous experience but no one in town could tell me how to, so I had to come up with my own method that I was comfortable with.

I know about the billet intermediate plate. What's the diff preload procedure?

I appreciate the exchange of thoughts

When the Diff. cover is put on it puts pressure on the bearings that hold the diff. in place. This cover can flex when power is applied and allow the ring gear to move out. The preload is determined buy checking the spacing between the cover and the case before the cover bolts are tighnted down. The Spacing should be 0.006 to 0.008" evenly between the cover and the case. If not, a shim has to be added or removed from under the roller bearing the cover fits to.

This ia all in the manual the can be downloaded from this site.

You can also buy a stronger Diff cover.

Ken

FWIW, Tim describes essentially the technique that Jerry Woods uses.
I took the tranny class from him, and tho is was a while ago, we spent
quite a bit of time on this. I'll dig for my notes later if I get a chance, but
even tho he has the P-tools ($$), it's apparently faster and more accurate
for him to use a marker on the gear for measuring engagement. (prolly
helps to have his eye too -- he's done it a time or two )

kim.