Interference fit bearing sleeve

[not done it yetParticipant @notdoneityet]

Ep90 gear oil? Do be careful that it doesn't contain extreme pressure additives that eat yellow metals.

I wasn’t aware that there was any form of oil pump in those Fairey overdrives. Are they not just splash lubricated? I had two fitted to my Series lll – one always ran very hot and its replacement was a far better unit (ran cool and drive selection was far smoother).

[Simon Williams 3Participant @simonwilliams3]

Posted by not done it yet on 13/07/2023 20:19:32:

Ep90 gear oil? Do be careful that it doesn't contain extreme pressure additives that eat yellow metals.

I wasn’t aware that there was any form of oil pump in those Fairey overdrives. Are they not just splash lubricated? I had two fitted to my Series lll – one always ran very hot and its replacement was a far better unit (ran cool and drive selection was far smoother).

Hopefully my comments re GL4 and GL5 oils cover this.

As to the "pump" concept, the main output gear is drilled radially with small holes in the lands at the bottom of the teeth. Hence oil brought up from the sump riding the gear teeth is squished under pressure through these holes as the teeth mesh, providing lubrication to the bearing inside.

Edit :

Bear in mind that oil for the final drive gear is from the sump of the transfer box.  In theory this oil is  kept separate from that in the bottom of the overdrive so hopefully the cooling of the inside bearing is better.  

Edited By Simon Williams 3 on 13/07/2023 20:53:24

[Graham MeekParticipant @grahammeek88282]

These damage marks could be ground out and some oversize rollers made from HSS drill blanks. This would effect a permanent repair.

Regards

Gray,

[Ian PParticipant @ianp]

Posted by Graham Meek on 14/07/2023 15:32:41:

These damage marks could be ground out and some oversize rollers made from HSS drill blanks. This would effect a permanent repair.

Regards

Gray,

I second that solution

Ian P

[David George 1Participant @davidgeorge1]

I have just had a thought. You can get over sized rollers to replace the original rollers in the bearings. You could get the bore re-ground to clean up then order oversized rollers to fit.

https://www.rgpballs.com/en/products/precision-cylindrical-rolls-rollers-and-needle-rollers/?gad=1&gclid=CjwKCAjw5MOlBhBTEiwAAJ8e1sIUYsMtsSAadQ46WskNmzYYmh5x2FaBsLBy3U9PSSIGsn4BkDtz6BoCGZ4QAvD_BwE

David

[duncan webster 1Participant @duncanwebster1]

Removed

Edited By duncan webster on 14/07/2023 17:18:50

[RedsetterParticipant @redsetter]

Is there any reason why the bush cannot be retained in the external housing, with the shaft rotating inside it? It would only need a light press fit, or Loctite. The oil holes could be drilled through after fitting.

Or isn't that complicated enough for you guys?

[RedsetterParticipant @redsetter]

A floating bush has been suggested earlier but I think it is difficult to predict how this would behave. As the assembly heats up the bush will expand, and tend to bind in the housing. To ensure that it floats properly it would have to be quite a loose fit, in which case it may not work well as a bearing.

[Gary YeadonParticipant @garyyeadon51936]

Just a thought if not already rejected create your bronze bearing sleeve in 2 stages:-

1. Press fit design OD from Limits and Fits leaving bore sllghtly undersize.

2. Once fitted to Housing Precision Bore/Ream to give Transition fit with shaft.

[Graham MeekParticipant @grahammeek88282]

In the original set-up the needle roller cage is retained onto the coupling that fits inside the above gear by two C-Clips. These retain and locate the needle roller bearing on the coupling. Pressing a bush into the above gear means it would not be possible to fit the leading retaining C-Clip, or the parts cannot be assembled.

This type of needle bearing assembly allows for some degree of self alignment, endwise within the housing bore. It may need several trials to get any pressed-in bearing, in the correct endwise position.

A few words of caution.

If this bush should seize at speed then not only is the gearbox and transfer box going to suffer, but it could also lead to an accident. It may also mean invalidating the insurance on the vehicle, as fitting this bush would be modifying it.

Regards

Gray,

[Dave HalfordParticipant @davehalford22513]

If they can do it over the pond ….. link

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