LSD's. How tight is too tight!?!

All technical questions and answers regarding starions, being modifications to maintenance.
Post Reply
sucka
I like starions more
Posts: 177
Joined: Tue Dec 21, 2004 11:35 pm
Location: Perth, western Australia

LSD's. How tight is too tight!?!

Post by sucka »

So,
I had an issue with my LSD a while ago. Suddenly it got really clunky on turns so I took it to a local diff specialist. He stripped it down and found a an apparently superfluous? shim that had disintegrated and put it together again without it stating it was good to go.

Except it wasn't, it turns out that the shim was an integral part of the whole LSD experience, without it the whole mechanism was a clunky and metal making mess.

I decided to tackle the whole job again myself and machined up a shim to suit what I thought it needed. Through the expert tutelage from Scum (he said if you can bolt it together then it must be perfect) I arrived at the magic number of 1.5mm shim width for the diff clutch pack.
Except now it's so tight that you can not turn the diff LSD by hand. It does do LSD stuff on the road whoever.

So my question is, how tight is too tight?
TOMSUN
Group buy King
Posts: 2391
Joined: Fri Sep 10, 2004 10:24 am
Location: Sydney (Liverpool)

Re: LSD's. How tight is too tight!?!

Post by TOMSUN »

Nice work. Is there anyway to adjust it and back it off?
Got any pics of the shim?
If you were in Sydney, I would suggested you to have a chat with Jason from "Gear Exchange" Diffs.

Good luck and keep the updates coming as my LSD needs adjustment after being punished on the drag strip (running slicks) :)
1985 JB Starion #157
coop1er
I've been here before
Posts: 240
Joined: Sat Feb 14, 2004 3:36 pm
Location: Adelaide

Re: LSD's. How tight is too tight!?!

Post by coop1er »

If you are talking about turning one axle relative to the other, then there is no way you could turn it by hand. But you should be able to turn the pinion easily.
sucka
I like starions more
Posts: 177
Joined: Tue Dec 21, 2004 11:35 pm
Location: Perth, western Australia

Re: LSD's. How tight is too tight!?!

Post by sucka »

Thanks for your replies.
Yes coopler I was talking about turning the centre, so wheel to wheel. Before the previous shim collapsed you could turn it fairly easily. Now with my new shim it's stiff as all hell. The centre can't be turned by hand but will slip on asphalt whilst driving. It does clunk a bit, like a competition LSD.

I did my first event with it this weekend, the Mount Clarence hill climb in Albany WA. This event often involves a wet surface for the first couple of runs and can be quite treacherous for the uninitiated, catching out a competitor in a Caterham who binned it on the practice run. The Starion is noticeably more tail happy on the throttle in turns, but I PB'ed on my second last run so I'll take that as a sign that a tighter LSD is a good thing. I'll check the magnet on the drain plug this week to make sure it isn't destroying the clutch pack.

Tomsun, there is no way to back it off short of pulling the centre out and machining more off the shim. There is a procedure to determine the shim width that involved a lot of measuring and mathematics, I totally ignored that in favour of a trial and error approach. But I am happy to scan it and post up if you are interested.
User avatar
Alspos
Flucking kwankers
Posts: 4107
Joined: Thu Jan 08, 2004 2:09 pm
Location: Melbourne
Contact:

Re: LSD's. How tight is too tight!?!

Post by Alspos »

The manual mentions Axle shaft turning torque 39nm or more. This is the torque mentioned by Coop1er (some call it break away torque)
Post Reply

Who is online

Users browsing this forum: No registered users and 9 guests