Bolt specifications for attaching Quaife LSD to ring gear

[chief tool]

A while ago I bought a Quaife LSD, but I am having alot of trouble working out what bolts need to be used to attach the ring gear to the LSD.

unfortunately both Quaife and the distributor that sold me the LSD have been unable to assist me with the specifications.

anyone who has done this before (or knows of someone who has) what did you use, and do you have specifications and or part numbers.

[ftjandra]

There is only one bolt kit and it's made by ARP and costs $150-200! MMS (Mazdamotorsports) sells it, part number 0000-02-6501-BT. If you are a member or can get someone to order it for you, they charge ~$150. Put that part number in Google and it comes up with a few places that sell it.

--Ferdi

[chief tool]

Thanks for the info...

I can see AWR sell it for $192.....

I'll see if I can get someone locally who can supply it, before I go to AWR.

unfortunately I dont know anyone with mazdaspeed membership, but I'll ask around.

[chief tool]

Next problem

Ok, I thought while I work out where is the best place to source the ring gear bolts. (probably AWR, and I'll order some engine mounts while I am at it, but I have to wait until I get paid this month)

I thought I'd test fit the Quaife LSD into the ring gear and use normal bolts so I can get started on the gearbox, which is going to be a mix and match of different gearboxes and some new parts.

Just as well I did go for the test fitting.....as it doesnt fit.

Getting the ring gear off was a piece of cake, done this a few times now, just drilled in to the rivet heads to about 1/4 depth, first with a 9/64" drill, then a 1/4" drill bit then to an 11mm (excuse my collection of imperial an metric drill bits) just deep enough to dislodge the head of the rivet.

Then punch the rivets out with a drift pin, here its is removed...about 1/2 hours work.



Quaife LSD centre with new speedo gear (and old rivets off to the right)



now here is where it goes pear shaped. The ring gear goes over the spigot ok, its a bit tight, I discovered heating the ring gear to near 100deg C (212F) makes it slide over the LSD much better.



but this is where it comes to a stop, the back part of the LSD just wont fit into the recess in the ring gear. I tried it in my hydraulic press, I loaded it up to a "reasonable" amount before deciding that it was not going to go. (note the photo shows an air gap...I took the photo after I pressed it back off, so the gear its just sitting there)



turns out that the back of the Quaife LSD is just a tiny bit larger than the standard open centre

150.2mm

150.0mm

What to do now.

In an ideal world, I would just take the Quaife back and get it "adjusted" or exchanged....but it came from the other side of the globe, I cant just walk up to the corner shop. If I have it machined locally i'll void the warranty.

So it looks like I will have to get the ring gear machined instead.

Admittedly I am using a 3.85 ring gear out of an early(1986) G series box from a 626, but theoretically the diff centre dimensions "should" all be the same, this is something I am unsure of.

I noticed that the Quaife techincal drawing does not show the dimension in question. it only lists the spigot diameter.

what a pest....maybe I should have held out for the MFactory group buy! but it wasnt on the radar at the time when I bought this.

[ftjandra]

Hmm, I am using the 3.85 final drive with a Quaife and it fit together fine. Mine is from an 97+ Escort though. Just for the hell of it, have you tried fitting the 4.105 ring gear on the Quaife?

--Ferdi

[chief tool]

I dont really have one handy to measure.

If there is anyone out there with a ring gear lying around, could you measure the recess diameter and post it up.....

at the end of the day though I will probably end up taking it down to diff technics and tell them to "make this fit into there"

I would be interesting to find out if there is any difference in the ring gears, or whether I just scored a diff that was built on a friday afternoon.

[FE3-323]

why do the speedo gear recess's look improper?

[chief tool]

The top part is machined bigger, dont know why



but it seems to fit better than the old one, there is less play, but there is a small gap



It is a new speedo gear tho,the new plastic hasnt stretched, the old one looked to be in fairly bad condition and wasnt worth getting off, when a new one cost me $22 AUD.

[therieldeal]

i'm using the escort ring gear, same as ferdi... it fit without much trouble (didn't need a press). unfortunately i didnt measure anything and its still installed in the car.

i have an idea that may be helpful... give me a few hours

[chief tool]

Thanks....The Mfactory ones look pretty good, I saw the pick you posted up...

[therieldeal]

I measured the mfactory diff with my (cheap) digital calipers and it measured out at 149.94 mm. they had two stock sample diffs and a ring gear to base these on... so it seems like your quaife is too big...

[chief tool]

Thanks for that....

The MFactory one would seem to be the same size as the original open centre.

It seems my Quaife might have been built late on a friday afternoon after all.

It also proves that the early model G series gearboxes can take an MFactory or properly built Quaife diff centre.

I might contact the place where I got the thing and see what they can do for me first before I decide for sure whether to machine it or the ring gear.