Oil pump cover-1275 ex-Marina engine

[ndevans]

Hi all.

What's the consensus on refitting the oil pump cover? I have a Marina 1275 engine in my Minor. The BMC manual says it should be soldered in place, but that's going to need a blow lamp and presumably plumbers solder. Can I use blue gasket sealer instead?

Also, is it possible to modify an oil pump from spider drive to slot drive?

Thanks,
Neil

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[philthehill]

The 1275cc engine oil pump cover is not soldered in place.

Only the 803cc/948cc oil pump cover has to be soldered in place and that is only because the thin pressed steel rear engine plate has a tendency to warp and leak oil.

The 1275cc oil pump cover just fits into the oil pump aperture of the 1275cc rear engine plate and is held in place by the rear engine plate and is sealed by the rear engine plate gasket. If a new rear engine plate gasket is used and the bolts tightened progressively the cover will not leak. Lightly grease the gasket when fitting. No need for sealant.

With some oil pumps the drive shaft can be changed from spider drive to slot drive but it does depend upon what oil pump or oil pumps you have.

Oil pumps with a woodruff key to locate the rotor onto the drive shaft are best as there have been cases of the rotor turning on the drive shaft when the rotor is only secured by an interference press fit.

I would recommend that you fit a new slot drive pump and be done with it.

[ndevans]

Ok thanks Phil.

When I last had the engine apart I did use a bit of blue sealant, and it does not appear to have leaked. I'll refit it with a smear of grease this time.

I'm only asking about the oil pump because I'm thinking of fitting a Kent camshaft. They only supply with slot drives, and I have a spider drive. I have a spare old oil pump that I think came off a 1098, which is a slot drive. It wasn't low on oil pressure when I took it out, but I guess for want of £20 it's best to get a new pump.

Cheers N

[philthehill]

The 1098cc oil pump is normally pin drive and has a slot in the oil pump drive shaft which engages with the pin at the rear of the camshaft.

Below is a pin drive oil pump.

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[ndevans]

The 1275cc engine oil pump cover is not soldered in place.

Only the 803cc/948cc oil pump cover has to be soldered in place and that is only because the thin pressed steel rear engine plate has a tendency to warp and leak oil.

The 1275cc oil pump cover just fits into the oil pump aperture of the 1275cc rear engine plate and is held in place by the rear engine plate and is sealed by the rear engine plate gasket. If a new rear engine plate gasket is used and the bolts tightened progressively the cover will not leak. Lightly grease the gasket when fitting. No need for sealant.

With some oil pumps the drive shaft can be changed from spider drive to slot drive but it does depend upon what oil pump or oil pumps you have.

Oil pumps with a woodruff key to locate the rotor onto the drive shaft are best as there have been cases of the rotor turning on the drive shaft when the rotor is only secured by an interference press fit.

I would recommend that you fit a new slot drive pump and be done with it.

So does the gasket go between the flange of the oil pump cover and the backplate, or does it go between the cover and the block?

Cheers N

[philthehill]

The only gasket involved is the rear engine plate gasket Pt No: AEG554B (MOSS)
The rear engine plate presses the oil pump cover down onto the rear engine plate gasket so sealing the oil pump cover.
There is no gasket between the oil pump cover and the rear engine plate and no need for sealer either as there is no oil to the rear of the pump cover.

1275cc oil pump cover on the right, 1098cc oil pump cover on the left.

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I would advise that you replace the two core plugs at the back of the block before you fit the rear engine plate as they are often overlooked and leak due to corrosion. Coolant then seeps down the block and you wonder why. Engine out to cure.

[ndevans]

Ok, are the core plus easy to replace? Is it a do at home job, or machine shop?
Thanks,
Neil

[philthehill]

The two core plugs in the rear of the block can be easily changed by the home mechanic with basic tools.

Unlike the small block engines 803cc/948cc/1098cc the core plugs can be accidently knocked into the block core if care is not taken when removing them as there is no back lip to restrain them.

The 1275cc core plugs are flat with a raised lip around the outside and are fitted concave outwards.