Gear clearance

[simonwri]

So finally got around to plastigauge the clearance on the input and idler gear. Now I have some measurements ...i think ...
I put it on both sides of the idler gear and both squashed to about 5 thou.... now its supposed to be between .004 and .007 so question is do i add the total of 5 thou per side or does the squish mean 5 thou overall... little confused.
The input gear squashed into what I’m assuming is 1 thou or less... which I think is correct as this has to be nipped tight .
It’s a brand new idler and primary .... so next job is working out the primary clearance
The brass thrust washer is .110 and I’m dialling the movement at about 30 thou so... upgrade is necessary as the book says .0035 to .0065... or have i misred this? I’m pretty the washers don’t come in .125+

[jockduck]

My autobox has worn surface on the box casing(early boxes have no oil feed to the needle bearing) I used the thickest thrust washers I could find but the clearance is outside the maximum in the manual(it was a long time ago) I get a clack noise when driving and lifting the throttle as the idler gear whacks the casing.
For the crankshaft Bronze thrust washer I made some oversized ones and I still have them (somewhere) you can get extra clearance if your "C" washer/ring is worn.
Jock

[simonwri]

Thanks jock
I think the bronze thrust is way under size
Are the available to buy?

[jockduck]

Sure, I shall have to dig them out and measure, any idea how thick you need? I could machine down to your required size.
Jock

[simonwri]

Current one is 110 but i need to tighten up so maybe around 125..

[jockduck]

Hi again, things just got a bit more complicated, There are different sizes of thrust rings I think there is a difference between 998 and 1275 also early minis had smaller crankshaft noses.
I check what I had, 3 genuine washers 2.125 x 1.694 @ 0.108, 0.114, 0.115.
I also have a smaller washer @ 2.0 x 1.568 x 0.122
The two oversize washers are 2.125 x 1.690 x 0.137 and 0.124. The oversize ones were made for a 1978 998 Manual mini, I think autos use the same washers as Manuals but please check the diameter you need, thickness can be modified no problem.
Jock

[simonwri]

Thanks Jock
I will check and get back to you

[simonwri]

[simonwri]

Yes so it looks like this 1970 1265 auto has a different size to what you have .
Am I measuring this right ?

[simonwri]

You can see the thrust sit into a larger diameter lip .
The actual crank diameter is what you stated for the primary gear

[jockduck]

Well I am puzzled, there is something odd about the photo with the ring, I would suggest the ring is the wrong way round, the internal chamfer is there for the radiused fillet on the crankshaft. Is there a groove in the sleeve gear for the ring to fit into?
I have no engines open at the moment to check, I have looked at various manuals but they are not of any help.
Did you check the clearance between the sleeve gear and the "C" washer steel ring with a feeler gauge ?
Jock
P.S. I have just remembered I have a couple of sleeve gears, I shall look at them in the morning.

[jockduck]

Hi again, I have 2 sleeve gears, one for 1.5" C/shaft and one for 1.625, weird thing the thrust rings look like they fit both, included photos but I don't think it helps you, sorry.
Jock

[mra-minis]

Apr 20, 2020 10:53:59 GMT simonwri said:

Thanks jock
I think the bronze thrust is way under size
Are the available to buy?

I make these for most if not all the major players... I also find that due to manufacturing tolerances etc I often have a few thicker ones in stock, the same for the early idler spacers as well.

[limby2000]

I know Martin ,you made me a custom sized one, at a favourable price thanks.

[mra-minis]

I can be contacted on [e-mail]

Thanks Terry, always appreciated to be ... erm appreciated

[mra-minis]

I can be contacted on [e-mail]

I have moved this thread to the "TRANSMISSION" section where it belongs