A10 oil pump spindle

[Stu]

Guys, got another one for ya.
I am having doubts about this spindle. I didn't rebuild the oil pump and turned the engine over a couple dozen times when I first built it.
When turning the engine over this time I noticed the pump doesn't turn, looking at the end. I'm thinking I damaged the worm spindle, please check the pics and advise. Cheers

[Stu]

Another thing that might help, at first I was turning the engine in reverse and the pump turned. Turning out the correct way it stopped. Im guessing this means that the under side of the spindle thread isn't worn much, hence turning in reverse but the used edge is buggered. Did I get that right?
I have added a pic of the worm to check if that's the problem but looks ok.

[Greybeard]

Off the top of my head comes: if the crank spiral gear is loose it may only turn one way. Turning it the other way might just be unscrewing the thread.

[muskrat]

G'day Stu.
They both "look" fine to me.
GB has a point. The worm has a left hand thread.
You also have a good point re wear on one side of the worm.
As the worm is only working on a short part of it's length it would only be worn on that section. A simple test would be to add one or two washers behind the worm to bring a fresh section into play.
Cheers

[RDfella]

Worm looks fine to me too. A little wear on the pump gear, but that's not unusual. Needs a closer look as something's not right. Tang broken off pump gear, perhaps?

[Stu]

The worm and pump are bolted right into place so can't be the worm unscrewing itself.

[chaterlea25]

Hi Stu,
If the pump is loose on the studs it may have "fallen" out of mesh ?
Loosen the nuts and see if the pump will slide towards the crank,
There MUST be a little play between the worm and gear when the pump nuts are tightened

John

[Stu]

The pump seems to have one position but I'll try that, thanks. When I zoom in on the picture I see lots of burrs in the grooves, like the crank worm cut into the spindle. Have a close look at he second picture, looks like the spindle was stuck and the worm cut it. I'll try making the pump work looser but I think the spindle needs replacing. To be safe I might just replace the worm and spindle, a third of the cost of a new better pump from.SRM. I'll let you know. Thanks

[Swarfcut]

 That worm drive has some heavy wear on close inspection, the pump gear looks a lot better than some, the worst ones are worn to a knife edge between each cut.

 So once more we're back to pump enigma. What to replace and what to spend?  First step is to gather as much information about the assembly and set up of these pumps, take your courage and take it apart. They are renowned for stiffness and lock up due to the creep properties of the pot metal bodies. My guess is that you will find some  tight spot, which must be resolved.

 Swarfy

[Stu]

I have attached a close up pic of the pump gear, you can see the metal had been cut and pushed down, I'm thinking that's from the worm gear turning against the pump while stuck, the pump gear being softer, takes the damage.
If I can find out the width of a good worm gear I could measure and see if the thread has worn down, but I'm told that's way harder than the pump gear so shouldn't get too damaged against a softer metal.

[RDfella]

Unless I missed it, I don't see mention of the pump being stripped down. Why not? That's the first port of call, especially as it's intimated it doesn't turn.

[berger]

i have seen the gears work ok when worn to a knife edge something must be wrong or wrong or even wronger. just saying

[muskrat]

G'day Stu.
I'm +2 with what RD said about the tongue and need to strip the pump for inspection.
The end plate and extension housing will need to be lapped on glass and wet & dry paper to get the marks made by the gears out.
Mark all the gears in relation to one another so they go back in EXACTLY as they came out.
Cheers

[Stu]

Sorry,I didn't mention but I did strip the pump down, cleaned and smoothed it out but didn't did the sandpaper. Never thought about the cogs maybe sticking to the end plates. Fully built, in my hands the spindle turns ok, tiny sections where it's sticking but I can turn freely with my fingers. I have read that I should put a piece of gasket under the spindle end nut shaft as there's a gasket under the main body, maybe that's making the body twist?

[Stu]

Does anyone know the width of the crank worm gear threads? Maybe I can measure and see if the threads have been flattened, making them not reach the spindle?