Looking Around For Pb Bearings

[dch1950 37 1 Cars]

Hi all,

I followed the thread on replacing inner/outer beam bearings last year with interest.

Now they have been fitted (presumably) I was hoping some more would be produce but it hasn't happened.

I started looking around for material(s) and came across these

 

Oilite sleeve bearings

 

Oversize - but maybe could be used as a basis for turning down to size (O/D & I/D) and pick your width.

Not a bad price either at £10 each (presumably plus Vat)

Any thoughts

regards

Dave

[dch1950 37 1 Cars]

Hi all,

schoolboy error on the I/D. I was scanning the list a bit too quickly.

I meant this one:

 

Oilite bearings - second (real ) choice

 

This is £7.49 and looks good to me - if I can find a shop to do the turning down for me at a reasonable price - its a goer.

Especally given if there is wear on the tube end you could also afford to take a bit off it or tidy it up with a wheel and then pick your O/D.

Nice.

regards

Dave

[shalmaneser 26]

Bloody hell that's a goer.

 

Two minutes work on a lathe and you're good to go!

 

Might order a few of them!!!!

 

How easy are they to machine? It's just brass really isn't it, piece of piss, nice to tools too...

 

Measured my shafts (oooh er missus) and looking at about 42/47mm ID, whats the OD? give it a few hundredths for compression....

[dch1950 37 1 Cars]

Bloody hell that's a goer.

 

Two minutes work on a lathe and you're good to go!

 

Might order a few of them!!!!

 

How easy are they to machine? It's just brass really isn't it, piece of piss, nice to tools too...

 

Measured my shafts (oooh er missus) and looking at about 42/47mm ID, whats the OD? give it a few hundredths for compression....

Hi,

Outer bearing OD is quoted on here as 53mm nominal

They don't look too bad at all do they ?

regards

Dave

[tri_longer 25]

How would these compare to the PB ones?

[dch1950 37 1 Cars]

How would these compare to the PB ones?

Hi,

I think they are good alternative. If you check the spec sheets for the material it offers what is needed both in terms of machinability, wear and of course self lubrication.

Have a look around , the material is well known.

regards

Dave

[Rippthrough 98]

Not very good for shock loads and unless you machine it with razor sharp tooling you can damage the oil feed to the surface.

And oilite dries out - it should be wick-fed from a reserviour.

[dch1950 37 1 Cars]

Not very good for shock loads and unless you machine it with razor sharp tooling you can damage the oil feed to the surface.

And oilite dries out - it should be wick-fed from a reserviour.

Hi Mate,

The Oilite spec sheets do say that sharp tooling is required to preserve the oil retaining surface of the material. As for shock load - the introduction of Super Oilite and Oilite 16 offers a good comparison with lower grade phospor bronze variants. The cost per unit is the factor that made it so attractive as worthy material to try out. Wick feed from a reservoir - never seen that before - what application is that ? Introduction and dispersion of both oil and grease as a lubricant is achieved by internal grooves (as per gti-si bearings) and presumably an oil hole in the ring that supports the outer beam oil seal would allow for that.

Get your point(s) but it doesn't rule it out.

regards

Dave

[tri_longer 25]

I'm planning a full strip, blast, powder coat and rebuild over winter and was originally thinking I'd be able to still get hold of the PB bushes but seems that's not going to be the case, so I'd be really interested to see how you get on with these oilite ones.

 

I'm an bit sketchy with getting things machined and looking through previous threads all this talk about interference etc goes a bit over my head so i'd be grateful for any advice on what you get done to fit these.

 

Only thing i have sourced is some grease nipples which i seem to get the impression are a good idea.

Edited June 28, 2010 by tri_longer

[dch1950 37 1 Cars]

Hi there,

I shall purchase a pair of these (oversize) sleeve bearings and then go to our local engineering firm in Leamington to get the outer diameter turned down and the inner diameter adjust to what is called a "slip fit" - taking the new arm shaft with me to check the fit. The bearing can the be fitted by driving it in with a mandrel.

I think it should be a good alternative to PB - which as you say seemed to be a one off.

regards

Dave

Will keep you informed

D

[Rippthrough 98]

Introduction and dispersion of both oil and grease as a lubricant is achieved by internal grooves (as per gti-si bearings) and presumably an oil hole in the ring that supports the outer beam oil seal would allow for that.

Get your point(s) but it doesn't rule it out.

regards

Dave

 

If you use grease on them you'll block the porous channels in the oilite structure that wick oil through the material, oilite is sintered together so there's porosity between the grain boundarys of the particles - it's the wicking force through those that draws oil through them to the surface - put grease on them and you stop that.

And obviously, in order for oil to move to the surface to give boundary lubrication at the moving surface you need to be able to replenish that oil supply if the bearing is in constant use rather than occasional motion - by feeding the bearing with oil - as otherwise the bearing will dry out over time - old lathes used to either run a small drip feed of oil onto the oilite bearing, or fed it via a large wick from sump somewhere - just like a candle wick basically.

Super Oilite isn't really much better at shock loadings than standard oilite is - it's the porosity that's the problem, and super is just a harder version that can take more load with less wear.

 

And make sure the machine shop replenishes the oil after machining them - soak 'em in hot oil for 10 minutes or so.

Edited June 28, 2010 by Rippthrough

[dch1950 37 1 Cars]

Hi there Rippthrough,

An interesting dissertation - thanx.

Grease is cited an oilite's own web site (technical data sheets) so I'll go by the manufacturer says.

"The lubricating mechanism determines the nature and orientation of the internal grooves in the bearing."

The movement of the arm in this bearing is nothing like that of a rotating shaft and I can't see lubrication being a problem -can you?

Yes I agree that giving them a good soak in hot oil wouldn't go amiss before fitting them.

an tapping in a nipple as well would be useful.

regards

Dave

[Rippthrough 98]

The movement of the arm in this bearing is nothing like that of a rotating shaft and I can't see lubrication being a problem

 

It's much worse than a rotating shaft as the pressure is in one point and the motion is oscillating...

[dch1950 37 1 Cars]

It's much worse than a rotating shaft as the pressure is in one point and the motion is oscillating...

Sorry mate but how does this make it worse ? It's not going to over heat and compared to a series of point contacts of the needle rollers, the load is distributed over a larger area. So worse than what in this instance? The 15 - 20 degrees of angular movement has always been the problem with the original bearings, especially when the crappy little seal goes west. I have suggested the use of a neoprene ring seal to get round that particular problem.

Carry on giving us your input by all means but I'll try them just because they are a lot cheaper than phospor bronze

Nothing ventured nothing gained.

regards

Dave

[Rippthrough 98]

Sorry mate but how does this make it worse ? It's not going to over heat and compared to a series of point contacts of the needle rollers, the load is distributed over a larger area. So worse than what in this instance? The 15 - 20 degrees of angular movement has always been the problem with the original bearings, especially when the crappy little seal goes west. I have suggested the use of a neoprene ring seal to get round that particular problem.

Carry on giving us your input by all means but I'll try them just because they are a lot cheaper than phospor bronze

Nothing ventured nothing gained.

regards

Dave

 

Because the shock loadings and the fact that you have oscillating and not rotating motion prevents any formation of a hydrodynamic oil film for lubrication and also removes most of the wicking action that occurs in the first place.

Peugeot didn't go to the expense of roller bearings over cheap oilite for nothing....

 

Anyway, if you insist on trying them, then I would suggest you put a little EP90 gear oil between the two bearings so it acts as a reservior of oil to feed the oilite, or, if you have it, a 30w suspension fork oil.

There's a neoprene X-ring seal that's a direct replacement for the Peugeot part, I'll see if I can find the part number if you want it.

Edited June 28, 2010 by Rippthrough

[Tom Fenton 1,536]

outer diameter turned down and the inner diameter adjust to what is called a "slip fit" - taking the new arm shaft with me to check the fit. The bearing can the be fitted by driving it in with a mandrel.

 

 

Don't forget that you will need to make the outer diameter a slight interference fit in the outer tube to stop the bush moving in the tube. Thus when you drive it in, you will find it closes up by a percentage of the interference nip. Typically I'd want 1 thou per inch running clearance over the arm shaft, over and above the allowance for the interferenace fit.