Crank Thrust Bearing material
Turbo Mini Forums

I'm going to make some oversized thrust bearings so that I can fit an 850 crank in a 998 block.

I was thinking of using phosphor bronze. I can get that in a hollow bar that I can slit in halves, machine the OD, bore to size and then part off to length.

Any alternatives to phosphor bronze? Does anyone know what the Rover items are made from?

Edited by Paul S on 18th Dec, 2007.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

i think standard bearings is maed whit a copper lead something. Look on youtube. Found it there erlyer today.

Hi,
I know they're steel backed.
Cheers,
Gavin :)

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I think that they're steel backed phospher bronze.

I bon't know for a fact, but they certinally look like all the phospher bronze bits we have in work.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I've pulled a thrust bearing out of one of the engines and it is steel backed and looks like bronze type bearing surface.

I think solid bronze will work ok.

Edited by Paul S on 20th Dec, 2007.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Why are they steel backed? Is it becasue of some thickness or heat considerations, or cost of the material?

I would guess at cost, the bronze is only about 0.5mm thick.

They look like they are stamped out of a sheet, hence you get quite a bit of wastage which you would not want with solid bronze.

I just need to make some about double the standard thickness.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Edit, scrap that, it wouldn't work

Edited by wil_h on 20th Dec, 2007.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Hi,
Is the steel backing to make then stronger?
I ask this as there's only that small tab stopping them from spinning round with the crank, there must be some tremendous forces involved when you press the clutch pedal!
Cheers,
Gavin :)

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No not really, as there is no metal to metal contact. Remember the oil-film.

I'm hoping that making them twice as thick will make them stronger.

As for retaining them, i'm not sure how at the moment. Making them with a tab like the originals will be a bit tricky. Plus the retaining slot disapeares when you machine the cap for a strap.

I'm thinking of dowling them to the cap with a couple of small pins. I believe Wil/Ben once used this method.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

We still use the dowell method.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

isn't phosper bronse sort of brittle?

i'd be worryng about it breaking up, especially with mini thrust pressures...

How about using 2 lots of thrusts, one as a bearing and one as a spacer and actually screwing them to the block, could the screws be located in the 2 "grooves"?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

You could make two work, but you'll need to surface grind them. When I pulled the turbo engine last time, the thrusts had worn 2 thou, but the outer edges of the thrusts had never been in contact with anything. Thrusts from the factory are very rough. I like to surface grind both sides of new thrusts.

surly despite there being an oil film the thrusts will still see a load, after all it has to go somwhere.

but with the 2 sets of thrusts yes ther would then be a lot more BL tolerances to contend with. lol

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Ah,

I get you.

yes I agree that rotational force shouldn't be an issue. as long as the thrust can't move, ifit has a bit of movement like some std setups i've seen i could see a locating tang breaking off.

I think the mounting surface would need to be FLAT.

but what do I know, i'm not an engineer!! lol