Morris Minor Owners Club

Hi all, is the oil pump cover that fits in the back plate necessary. Can I leave it off. Im fitting an Ital engine and the moggy back plate wont go on with the pump cover

You must have that cover - so either carefully modify the pump/.and or cover until it does fit - or get a different low profile pump. There are many different pumps out there - for a 1275 engine you need a long shaft pump. Other option is to modify the 1275 backplate and use it - problem will be getting the starter in the right place (I assume you are using the 1098 engine flyhwheel?) - probably need to cut-and-shut a section from the old backplate into the 1275 backplate! You will also find the small engine backplate will be tight over the rear main bearing cap - but that's easily enough overcome.

The original back plate which has cracked right across is the same as the new one except the hole for the pump cover which is off centre. you seem very sure that it is needed, why? I think it is there to stop any leak from the pump contaminating the clutch

Keep the cover and move the hole in the backplate, no point chancing it, I always tend to think manufacturers do things for a reason, as if things weren't needed they would save the money!
beehive springs come to mind! Also putting the brake cylinder bolts in wrong.

Why "must (you) have that cover"?

Moving the hole is not an option you cant just relocate it. It is a 4" is hole with a recess for the cover. I don't know why it is in a different location from the one I had. This one was kindly donated by bigginger. If someone has a number of back plates perhaps they could check to see if the pump hole is in the same place on all of them. I still have the cracked one if anyone in somerset has lots. bigginger, I think you said you have several

Well yes the recess has to be milled as well, I did mine with a router and tungsten bit, it's cast iron so machines well.

As bigginger says, why do I need the cover? someone said if you don't need it, it wouldnt be there. have you seen modern cars!!!

I don't know why the 'hole' is in a slightly different place - because the pump is in the same place - it's just that the later pumps are a bit bulkier - and have much better pumping ability! I 'think' if you slim down the pump you should get the cover on. Leave the cover off at your peril - but oil fume will then be able to enter the bellhousing(there is a vent/drain hole under the pump) and that won't be good for the clutch! Maybe that drain hole could be plugged - the pump doesn't leak, so I don't really see the need for it!

As there seems to be no definative answer; leave it off, and see if it fails---I remember Hal saying something similar in 1969!!

If you leave it off - then you really must plug that drain/vent hole. I'll be doing the job myself soon - so will find out exactly what's involved!

because the pump is in the same place

Don;t be too sure of that, according to an owen burton book the Ital backplate has a larger hole for the pump and is radially displaced by 5mm, the mains 'hole' is also larger

Well - the camshaft runs in the same place as on the smaller capacity engine - same timing chain etc and same front plate/timing cover - so the pump being driven off the back of the cam IS in the same place ! The 1275 block is of course slightly longer - so in that sense the pump is moved back by ~ 5mm - hence the need for a 'long shaft' oil pump (to reach the cam tail) , but otherwise it hasn't moved. And the backplate obviously moves back with the pump - so no difference in spacial realtionship there.
Yes - the mains housing is larger and the hole in the backplate there will need opening out.

There is some confusion here, I have actually done this, and the hole definately needs moving, and if it was radially moved the position regarding the cam and crank would not be effected, would it? So at this moment in time I think you may be wrong bm.

Ehhh?
The pump can't be moved unless the cam is moved too! And it's not!

I'll let you all know next week. My 1275 block will be back from machine shop and I will be starting the rebuild. Roy, did you figure out the best pump to use yet?

Why does the hole need moving then?

The best pump (for pumping ability ) is the 'steel backed' pump - but I'm not sure which pump has the lowest profile.
I don't think the 'hole' does need moving - I can see no logical reason why it should move - I think it's just a matter of possibly reducing the body of the pump with a file to get clearance!

Ok, I just moved mine for the hell of it!!

Maybe !
What I did notice is that the cover (and hole) in the 1275 backplate are slightly larger diameter - but I think on the same centreline. I believe the larger diameter is simply to clear the later more bulky pump body.