5 replies to this topic

[minigeorge]

Hi, Im still restoring my brothers mini and now putting the engine and gearbox back together. But I  think I have a problem with the idler gear end float being too much. I have took some pictures to show  the sizes below.

 

I followed the guides online and fitted the thrust washers, idler gear , the gasket and the housing and torqued up the bolts. I then measured the gap between the thrust washer and gear box case   which was 0.046in. The thrust washers were 0.131in and 0.134in.  I have read that the end float should be 0.004 to 0.006. So if It was 0.005 I would have a gap of 0.041in  that needs to be made up. If I add up this with the combined size of both thrust washers and divided  it by two I would need two thrust washers that were 0.153in each. Can anyone confirm if I have calculated this  correct because I have looked on various sites and they dont seem available in this size. After taking the gasket back off and measuring where it had been squashed it was 0.030in which I have read is the correct size.

 

 

The flywheel housing part number is  (dam 2929 4d1291) and the gear box is a+ (dam 5626). There was no idler gear fitted when my brother bought the mini so this is also a new pre a+ one with conversion bearings fitted in the casings so it will fit.The flywheel housing does have some wear around where the idler   thrust washer would sit but I didn't think it was a problem as the original  lines pattern in the casing is still mostly visible and the washer still sits flat. There doesnt seem to be any wear on the gearbox thrust washer  side. 

 

Can anyone confirm if the gap is too big, what might be causing it and what to do to fix it. Thank you

 

 

 

 

 

 

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[Spider]

Your procedure here looks and sound fine.

 

Off hand, I think the thickest standard thrusts available is 0.138".

 

Looking at your Flywheel / Transfer Housing, it does appear worn on the Idler Thrust Face.

 

A couple of ways to repair this;-

 

1)  Measure the depth of the wear, then dress that entire face flat, Then machine the gasket face back by the same amount as the wear and it would be a wise idea to take another 0.003 - 0.005" more off, then go to thinner thrusts. This will allow for adjustment down the track in a normal way.

 

2) Make a custom Thrust Washer.

 

I've done them both ways. Usually with a worn thrust face like you have, on the Transfer Housing, I prefer to just dress them as described in 1) above. When the Thrust on the Gearbox becomes worn or chewed out, that's when I usually go to a custom thrust washer.

 

Another fix is to simply get another Transfer Housing, though I like to discourage this as in a few years, I can see we'll all be scrounging for these parts as they will soon become thin on the ground and really, this is an easy fix taking minutes on a mill.

[minigeorge]

Thanks for the help. My brother bought another case as he wants it finished as soon as possible and is away so didn't have the time to get the other machined. It has now arrived though and has closed the gap to 0.006-7 but I'll still probably get another washer to bring this number down.

Should I replace the idler bearing in the new case, I was going to buy a new bearing off ebay but the bearing in the case is torrington and I have read that these are better quality then some of the others that you can buy.

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[Spider]

At 0.006-7" end float, yes, I'd bring that down. The lower limit is 0.0035", but I don't like to go any lower than 0.004".

 

In regards to Bearings, yes, I would replace them, but go for a recognised, established name bearing, pretty much anything out of France, Germany, USA and Japan will be fine, but beware, there are counterfeits getting about. I went looking for these recently and found some good ones from Japan.

 

The number for this bearing is BR-142212.

[minigeorge]

Hello, I have since changed the washers and the endfloat was slightly over 3 thou, But after actually fitting the gearbox back to the block and putting all the bolts back in the clutch case the idler gear become tighter to turn then it should be. But I have another washer that is about 1 to 2 thou thinner. But the washer that needs changing has flat top edges at the top hand bottom and inner hole has 2 extra grooves cut out. Is it ok to use the washer that is fully round in place of this one or does the one with the extra grooves allow more oil to circulate the bearing in the case.

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[Spider]

The upper one appears to be non-genuine, all the same, it should be fine. I've had to make a few, I do put the 2 half holes on the ID, but don't worry about the flats on the OD, they are I'm sure only for job holding in manufacture.