MiniSpares X - pin (cross pin) diff assembly
Turbo Mini Forums

OK, after all your advice I bought the MiniSpares one (C-AJJ3385) and went to do a trial assembly today (trial because I haven't got the CWP ratio I want yet so I just trialed it with a 3.44 CW).

I remember reading on this forum on one of my earlier searches that someone (can't find the post now!) had found it tight with the new fibre washers so had used old ones, so I decided to measure them first.....

New ones supplied by MiniSpares with the diff, 0.030" and 0.034" (not even within 10% of each other !!!)

So I measured some of my old ones and all were 0.032" on the "used" part and 0.035" on the unworn bit.

I had also bought a new "competition" single pin a while ago (before I decided to go x-pin) and the two fibre washers I bought at the same time measured up today at 0.043" thick !!! so I decided to try the used ones I had at 0.032".

It assembles fine, certainly not tight, just the opposite - with a DTI I can measure 0.014" end play on either one of the output shafts (probably not 0.028" overall as there is play in the small planet gears to the cross pins which my DTI will also be measuring) but certainly more than I expected.

BUT.... if I push the two shafts together (as if the washers were thicker) and turn them in opposite directions, it feels like a bag of nails, as if the tooth profile is all wrong, but pull them apart against the two 0.032" washers at it turns fine.

So I'm assuming the gears are meant to run with a fair amount of clearance/backlash but the correct amount will only be determined by the fibre washer thickness.

Anyone any ideas as to what it should be ???

BTW, I'm not slagging off MiniSpares here, it looks to be a very well made piece of kit but there is no technical info provided and the last time I tried to get technical info from them over another product, I had no luck, so I'd rather hear other people's experiences, if you see what I mean.

Rod.

Schrödinger's cat - so which one am I ???

The gears are not designed to be run with them 'pushed together - this is not aligning the pitch centres of the gears. They will thrust outwards in normal use, so test them this way.

I agree, and they feel a lot better allowed "outwards", but by how much ???

On any normal bevel, hypoid etc., gear assembly there would be a defined clearance/backlash/endfloat (or however the designer chose to specify it) but all I have is an instruction leaflet that says "use the new washers" (even though they are both different sizes), and a selection of different thickness old and new washers !!!

I suppose I could dig out some "engineers blue" from the bottom of by toolbox but....

ie, any thoughts on how much they should run apart (defined best by end-float on the output shafts as that's easiest to measure)?

Rod.

Schrödinger's cat - so which one am I ???