oil pump removal A10

[chaterlea25]

Hi David, shabashow and ALL
I have just had a chance to go and look at a couple of sets of crankcases I had in storage to check if
there was any "truth" in the info from Roy Bacons publication
Anyway the spare cases I have CA10 and DA10 are both flat across all 3 of the oil pump mounting holes which is also flat with the outer mating face of the crankcase
I have checked a couple of oilpump bodies and these are flat as well
Why would BSA add another machining operation to just lower one point on the cases surface ???? ???? ????
It doesnt make any sense  

Since SRM supply a one piece gasket and with the good number of A engines I have worked on I'm quite sure
it would have been spotted if there was a difference on the pump mounting surfaces

Regards
John O R

[shabashow]

My washer has done sterling service for the last 4 years or so, and will stay where it is until I need to remove the pump, hopefully not for a very long time, therfore I can't verify the flatness of my cases or the underneath of my pump. ;-)
This begs the question - why isn't the original gasket big enough to cover all the appropriate holes and the stud positions. I can't see how saving less than 1 square inch of paper and adding a fibre washer would make the job in the factory any easier and cheaper. The mindset at the time would look for the cheapest, quickest and easiest form of fabrication, I'm guessing. Why use two pieces when one would do unless there was another reason?
john

[bsa-bill]

Why would BSA add another machining operation to just lower one point on the cases surface huh2 huh2 huh2

My understanding was that they didn't and that the PAPER washer is just to keep the pump up level as the rear studs have a paper gasket.

if you have a fibre washer in there you risk distorting the pump and breaking something ????

As to why BSA did it this way instead of a one piece gasket I can only assume the ways of accountants then was as mysterious as it is now

[dpaddock]

Well, Bill, if the pump surfaces aren't coplanar, the risk of pump distortion and breakage is definitely increased if one doesn't compensate.

Another thought re this might be that there were a shipment of pump bodies that had faulty faying surfaces, and BSA ended up machining them to make them usable.

Anyway, check for this when reassembling.

David

[Beezageezauk]

BSA's service sheet number 215 covers the reassembly of the A Group engines and states that "Before mounting the pump, replace the thick washer so that the holes match, and the round fibre washer on the third stud".

The term "Thick Washer" is obviously referring to the gasket and the round fibre washer is there for a good reason.

I personally put a straightedge over the face of the pump and make a suitable fibre washer depending on how much daylight I can see.

Beezageezauk.

[dpaddock]

Ah! I knew I'd seen this is one of the Service Sheets!
Thanks, Beezageezauk.
David

[nagrod]

I received my new worm gear drive from SRM yesterday, it's now residing happily in the pump, the pump turns easily enough, I'm sure there will be a little bit of "wearing in." My next step obviously is to get the pump back in its position. To avoid repeating the problem that caused all this I will be sure that there is a gasket under the forward stud hole this time. A straight edge along the base of the pump shows the two surfaces that mate to the inner case surface are not co-planar, the forward stud will require a thinner gasket. Besides pump to case attachment being secure I am thinking that the centerline of the worm gear drive has to be very close to the centerline of the tach drive spindle so again I don't repeat my original problem of breaking the tangs. This I think will have to be by eyeball, trial and error and seeing how the spindle rotates. As per John O R's advice I removed the pump easily by removing the 3 studs and slipping it out. I am wondering now since the studs have been removed from their 51 year resting place if I should use loctite when I do the final mounting of the pump. And also maybe the four screws that hold the pump body together! The nuts that hold the pump on the studs do have star washers but I'm afraid that Murphy's Law is lurking waiting to strike again.

Thanks
Rick D

[chaterlea25]

Hi Rick,
Ive just had another thought after reading your last post
Since you observe that in your case a thinner washer  is needed for the front stud???
The main pump body and the front portion are separate pieces, its probable/possible that these can become misaligned to some degree as its only the screws holding the pump together that keep the bits aligned????
I dislike the star washers intensly as they chew into the soft pump body 
I normally fit the pump with 3 suitable allen screws with thick steel washers under the heads, I spotface the damaged alloy flat so the washers will have support
A little screw lock on the threads if you feel its neccessary,
I would put some on the screws holding the pump together

Also check for any rot in the pump body, they crumble away with age

Regards
John O R

[nagrod]

I've been fiddling with the pump assembly a little, trying for the correct alignment after installing the new worm gear drive. I'm having a small problem with free rotation. It binds in one direction then I take it apart, it binds in the other direction. I can't tell if it's only because I'm turning it via the tach drive end with a screwdriver, it does not rotate freely enough to turn it from the worm gear itself. The parts rotate freely when the pumps is apart, not a sign of trouble. The back end does show some wear from the gears on it. I'll try dressing that a little, do a final assembly and see what happens. I keep wandering over to the SRM site and looking at their pump. I do not want to put this thing in, button everything up and then have it bind when there is some real force driving it and end up damaging the worm drive or worse. I sank some money into the engine this summer and so not want to create a problem there. What's another couple of hundred!

Rick D

[muskrat]

G'day Rick,
                thought I'd add my 2cents worth in. The pumps can be a bit of a pain to assemble so that they run free. I find that by spinning the spindle while tightening the 4 screws a little at a time in a cross pattern and a gentle tap with a hide mallet works for me. If it binds I start again. I replaced the studs with allen head screws and use an inch/lb tension wrench to tighten evenly, with red loctite . If the pump is not co-planer I shim to suit. Doing all this without the worm in place I can check the pump spins freely. Once I'm happy I put the worm and nut on.
Cheers

[nagrod]

the saga continues - I've taken all the good advice I've gotten here and gotten the oil pump back together, it rotates by hand freely in each direction and I'm just waiting for the loctite on the screws  to set up before I install it in the engine. I took a look at the gasket though and the holes for oil flow are smaller than the holes in the engine case. Is there any point in opening these up? Seems to me like they would offer some restriction to oil flow but maybe it's inconsequential?

Thanks

Rick D

[bsa-bill]

Compare them also to the holes in the pump, can't recall from memory if the pump and cranckase are the same size

[nagrod]

I did end up enlarging the gasket openings around the oil ports. The pump is now back in place and everything is buttoned up. And the tach drive, the reason this all started is working again. Now on to the next thing!

Thanks for all the help and advice and info!!

Rick D