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MG MG Y Type - Oil Pump Issues

Hi,

Just assembling my oil pump....

When the cap is removed the end float of both gears is 004", this is measured by using a straight edge across the top of the pump body and passing a feeler gauge between it and the top of the gears.

However, when the pump is fitted and the bolts tightened correctly, the pump exerts a great deal of resistance on the camshaft making difficult to rotate.

Any suggestions?

Thanks

Rob
Rob King

Just some thoughts:

There are different lenghts bolts. Are you sure you fitted the right?

I trust you're only using a gasket at the foot of the pump.

Was the top/end plate skimmed? If so maybe the shaft gets stuck when tightened if too much was taken off. The remedy would then be to deepen the recess?

Are you sure that the problems is in the pump and not in the camshaftbearings that may 'load up' when the forces of driving the oilpump are exerted?
Are you using a new pump or did you fit new gears, or are you using the old pump?
If you are using a new parts, maybe you could try the old parts to rule out other causes.
Willem van der Veer

Hello Rob. Since the clearance is so small I would first check to see if there is any dirt on the ends of the gears or on the gear teeth. then check to see if the shaft for the driven gear is perpendicular to the face that the oil pump attaches to in all directions. If it isn't it will cause the driven gear to lean and rub. You will need to take the pump off to check that. Take the cover off and look at all parts to see if you can see a smooth bright spot where parts have been rubbing.

Butch
R Taras

Hi Rob,

Maybe the oil pump drive gear is meshing too deep in the cam shaft gear, try using a thicker gasket under the pump body to see if it makes a difference. The other thing to check is how much float on the cam shaft, is the cam shaft too far or not far enough into the end bearing. You may need to increase the float a little to allow the camshaft to adopt the correct position in relation to the oil pump gear. You could also try putting a little engineering blue onto the oil pump drive gear then turn the camshaft. Once the pump is then removed you will see how the gears are meshing.

Hope this helps Chris
C A Pick

Thanks for all of your suggestions guys.....after checking everything again Ive come to the conclusion that its what Butch suggested....

If I assemble the whole thing leaving out just the driven gear shaft there is no resistance...

So if the shaft is not perpendicular to the face of the block what is the best solution?

...big hammer?
Rob King

Hello Rob. Actually a brass hammer is best, else a block of aluminum between the shaft and a hammer. Check with a square each 90 degrees around the shaft. Work one plane at a time tapping to get it straight. The shaft is driven into place in the block with about a .0005 interference fit. The shaft could get accidently knocked out of alignment just by tipping the block over too hard on the floor or banging it on the edge of a hot tank to clean it. Take your time and be patient.

Butch
R Taras

Thanks Rob for keeping us informed about the cause.

When I fitted a new shaft (bought from the OCC) in my engine I noticed that it was looser than the old shaft. I 'glued' it in with Loctite bearing fitting 'glue', slid over the gear and left it to cure overnight with the engineblock on it's side on the enginestand.

Just for my information: what is the other gear called? The driving gear?
Willem van der Veer

This thread was discussed between 18/07/2013 and 24/07/2013

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