Mythbuster: continuing project thread of my 1303 '75

[ricola]

I'm very interested in how you get on with this as I have an LSD sitting on the shelf for my G50 too! Did you find any god reference material on rebuilding it and installing it with the correct tolerancing?
Rich

[Bruce.]

oh..... and the front diff axle flanges from a 964 C4 are "964 332 209 01", if you need that number.

Interestingly, the gears inside that front diff (which I guess the subs splines attach to) have a 950 part number and are straight from a G50 box (plus 928 & 968)

[Bruce.]

The 996GT3 catalogue is perhaps clearer (i got it to open at last).

http://www.porsche.com/all/media/pdf...T3_KATALOG.pdf

Like the GT2, it lists the LSD (the only diff) as part number 996-332-083-9B. It is hard to read from your photo the last two digits but could this be your diff (or does it end "00" or "01").

The GT3 & GT2 use the 999-217-152-01 bolts (only option listed).

(also corrected the part number above for the other bolts, as you mentioned)

[Wally]

Thanks Bruce, the diff number ends with 9B, so its spot on.
I'll order the 999.217.152 bolts then

It will be fun to later couple a 1200 T1 engine to a 996GT2 equipped diff with a Gears Transmission friction plates upgrade

[Wally]

Bruce,
By any chance, do you also know the correct torque setting for these bolts? I did came across it once, but didn't save the info then...:-(

[Steve C]

Hi

Does this help?

Steve

[Bruce.]

Steve:
From what I can gather, that is the "street" LSD.
Wally's LSDiff is the motorsport version which is tighter than an inappropriate simile.


Wally:
For the torque settings, I think the safest plan would be to send another email to Guard. I'm sure he will spare 2 mins for a customer. Internet chatter suggests 50ftlbs+90degrees with locktite for a standard diff but I wouldn't trust that spec without confirmation from a reliable source such as Guard.

[Wally]

Originally Posted by Bruce.

which is tighter than an inappropriate simile.

Wally:
For the torque settings, I think the safest plan would be to send another email to Guard. I'm sure he will spare 2 mins for a customer. Internet chatter suggests 50ftlbs+90degrees with locktite for a standard diff but I wouldn't trust that spec without confirmation from a reliable source such as Guard.

Well, I am no customer really. Paul send me a few old used disks from his own old stock as a favour to try out in my bug. He has sold most of the company a few years ago, but carries still his name. I did already send Paul a message of course from my new email adress. Hope he receives it as he probably knows this value by heart. So cool he wants to help a bugger out!
Hope to be able to pick up the bolts tomorrow afternoon as they were in stock at the central porsche dealership over here.

[Steve C]

Originally Posted by Bruce.

Steve:
From what I can gather, that is the "street" LSD.
Wally's LSDiff is the motorsport version which is tighter than an inappropriate simile

Hi Bruce

I thought that he was after the part number for the bolts.

Steve

[Xellex]

Wally, sorry for changing the topic, but could you detail the modification you did to the oil filter pressure relief ball/spring setup? I was surfing the keversite.nl forums with google translate, but it's not that good :P
Thanks!

[Wally]

Easy: drill 5.0mm hole in top above ball-spring, tap with M6 tap and install M6 bolt with lock nut. Install with loctite

These are/were the original bolts: 22.0 mm shank length. I need 2mm more (i.e. 24.0-24.5mm).


I do hope the ordered bolts are the correct length, but how could they not be?

[Bruce.]

Hi Steve,

I looked in the same place as you, the 996 carrera catalogue but the optional LSD for the 996C is different from the "motorsport" LSD used in the GT3/GT2 and the bolts specified for each are different.

Hopefully, the bolts will fit with the G50 Crown gear. It is difficult to see how they wouldn't.

[Wally]

Picked up the correct bolts for exactly my differential and got a mail from Paul to use 120 lbs.ft and a drop of red Loctite.
There is a difference in length, but not exactly as much as the difference of the flanges.
Anyway, it will do fine I think.

[Wally]

Just reassembled everything and very happy I got the spacers and bearings pressed on again without any trouble. Ring gear was extremely nice and tight fit on the much later dated diff housing. The machining on these parts is amazing!

[Wally]

After a lot of work pulling the engine forward far enough to get the thicker diff back in, I got the engine back in its place again. Filled tranny with new synthetic 75W90 Valvoline and reused the O-ring n the side cover (even though I still have a new one from the gasket set). If you turn one wheel, the other one turns in the same direction as it should with a LSD It turns nice and smooth by hand.
Got the engine running again and went for a test drive.

No extra noises, all seems just fine and dandy. Did a deliberate lighting of the tires in second gear (cold and damp road) and that felt different somehow, more aggressive in a way, but not out of control.
Car is still stupid fast and seemingly effortless at doing so.
At home, tranny is still bone dry as before.
All in all, this was relatively easy sailing, though I didn't know that up front..
Gotta love orginal parts