Oil pump worm gear question

Gents,
How much play / back lash should there be between the crankshaft worm gear and the oil pump worm gear?

My "guts" say no more than barely perceptible.

Slick

I would say 'as long as there is meshing contact' since it only 'drives' in one direction.
Ta.

needing said:

I would say 'as long as there is meshing contact' since it only 'drives' in one direction.
Ta.

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I'd say the same, once the backlash is taken up it won't make any difference how much is there.

daveparry said:

needing said:

I would say 'as long as there is meshing contact' since it only 'drives' in one direction.
Ta.

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I'd say the same, once the backlash is taken up it won't make any difference how much is there.

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if the backlash became so severe, it is possible the start of the driving worm would jam on the start of the driven worm. This could result in loose metal in the timing chest. I had a similar occurrence with the worm in my speedo gearbox .... the jam spun the GB with the wheel rotation.

Barely perceptible play is normal, anymore is not.

Slick

Hi texaslick.
Re your: "...if the backlash became so severe, it is possible the start of the driving worm would jam on the start of the driven worm..."
Has this happened to you or has anyone else experienced this 'possible' failure?

Apples and oranges. Speedo drives are notoriously under lubed / maintained and usually the ring gear shears the centre of it's teeth against the driven teeth as the housing should have been effectively clamped during rear wheel assembly.
Ta.

It’s only the oil pump shaft (driven), which I would be of concern with. If too much end -float on the pump then I would investigate the internals and may be flatten the brass plate if it’s heavily grooved by the gears. The oil pump studs and paper washer dictate proper location to the worm gear.
Cheers,
Thomas
CNN

Gidday Eddie
Lots. here is the reasoning.

For example, If the crank has 25 thou end float, it moves laterally 25thou.

if the back lash is less than this, there will be impact from the c/shaft gear teeth to the pump gear teeth. any impact here is not good.
crossed helicals are not good at end float control.

Therefore the backlash should exceed the c/shaft end float. This is probably why there is a max end float figure given.
Excessive back lash in this application will have no detremental effect.

have a look at a used pair. the indicated depth of engagement is far less than tooth depth. This seems to have worked well.

Contrary opinions welcomed. bradley

I think FastEddie should be more specific as to what he is seeing, and what his concerns are. Backlash or end float?

Certainly, excessive wear in the oil pump drive worms is a situation to be investigated, and corrected.

Slick

texasSlick said:

I think FastEddie should be more specific as to what he is seeing, and what his concerns are. Backlash or end float?

Certainly, excessive wear in the oil pump drive worms is a situation to be investigated, and corrected.

Slick

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I'm just curious having seen a little more back lash between the two gears mentioned, it looked like more than I thought correct, but the explanation about allowing for crank end float probably explains it, as neither gear shows particular signs of wear.

So I'm kinda assuming all is good.

I would have thought that the end float would be taken up by the rotation between the gears. If there is no noticeable ware in the gears there maybe issues with the oil pump mounting location which well effect the gear meshing. But how much play is there an does anyone know what it should be?