oil pump removal A10

[nagrod]

My '60 Super Rocket, A10 engine is so close to getting back on the road, but one thing I want to solve before that is a problem with the oil pump. Oil delivery seems fine with a steady return stream but the little tabs that are on the end of the worm drive gear have broken so that the spindle that the tach drive cable fits into is no longer driven by the worm gear. I can see this by removing the connection piece that the tach cable threads onto on the engine side. I have this part on order from SRM. But to replace it and see what is going on I need to remove the oil pump. My big question is after I remove the outer case does this give me access to the pump or are other things in the way. It's been years since I've done this and I've forgotten and my Haynes manual and service sheets offer little help. Next question is can the pump be removed in one piece or do I need to take it out in pieces, and lastly should I drain the tank first?
Thanks in advance for any and all answers!
Rick D

[chaterlea25]

Hi Rick,

Drain the oil.
You can remove the oil pump after removing the outer cover
It will come out in one piece
Forget what the Haynes says about undoing the crank nut etc!
Lock a second 1/4 BSF nut to the nuts on the pump studs then unscrew the studs from the crankcase
this will let the pump drop out of engagement with the worm drive on the crank
It can be a bit finniky to get the circlip out that holds in the drive gear in the pump 

Fit a new greased gasket to the pump on replacing, I dont like the idea of a fibre washer on the front stud
I mahe a one piece gasket that takes in the 3 studs
SRM use an A65 gasket but that needs to be cut or folded

HTH
John O R

[nagrod]

Thanks John - Sounds like a good plan. I am thinking I can use the nut from one stud to use as a locking nut on the other and then swap the two. If all goes as planned I'll give it a try tomorrow! Thanks again for the help!

Rick D

[nagrod]

The studs are out and the pump is off. Now I just need to wait for the part from SRM and back it all goes! Getting the studs out was easier than I expected. The nuts used to hold the pump in place were too thick to both fit on the stud and lock together so I borrowed two with a thinner profile from the tach mount, locked them up tight and it worked beautifully! Now if I could only figure out why the two ears on the driven spindle broke! I'll probably take two pics and post a separate question. Thanks again.

Rick D

[dpaddock]

In my notes somewhere there is a caveat re the oil pump mounting gaskets. I recall that the round fibre washer is thicker than the paper gasket, and if the pump is assembled without noting this difference, it will not seat properly. As a result, the pump body will distort and eventually break.
A search of the Forum files will confirm this (or not).
Perhaps I'm wrong, but do check this out.
David

[nagrod]

Thanks David, I think you have found the answer to my question of how this happened in the first place(broken tach drive). When I removed the pump there was the paper gasket but no fiber gasket on the forward stud. I had the pump out some years ago and must have put it back without that forward gasket. I think this may have cocked the center line of the pump off from the centerline of the tach drive spindle allowing it to stress the tangs on the worm gear and eventually break them. See my other post "oil pump driven tach drive broken" in this forum.

Rick D

[shabashow]

When I built my A10 up I mounted the pump temporarily on the two studs and gasket and found a suitable diameter steel washer to take up the place of the fiber washer. I ground it down to the right thickness so it would just slide in under the front stud hole. That way I could be sure that when I mounted it permanently, there was no way the pump body could distort. Don't know why we rely on a fiber washer, which can come in varying thickness and compressabilities, instead of using my method. As far as I know I'm the only one doing it this way. If there's something wrong with this method, I'd like to know. So far, its given no problems after about 5000 miles.

[chaterlea25]

Hi shabashow,
I'm puzzled as to why you think a steel washer is needed???
The surface on the crankcase should be flat
The oilpump should be flat
So why introduce a solid object between them?
The gasket betweem them will compress somewhat, where does that leave the steel washer?

I make a one piece gasket which spans all three mounting studs
that way they all get tightened the same and the gasket compresses equally across the joint

Anyway thats my method??

Cheers
John O R

[trevinoz]

I agree, John.
                           The pumps always need to be checked for "flat" across all 3 mounting points.
They are not always so!
                                       Trev.

[manosound]

SRM now supplies a one-piece gasket,  as  John describes.

[chaterlea25]

Hi All,
The gasket SRM supply is an A65 one, these have the mounting studs farther apart for the 3rd stud
its neccessary to fold or cut this to avoid the springiness(??) of the material pushing the gasket towards the rear wheel
The gasket holes are a loose fit on the studs 
You may ask what difference this makes
Well!!! Apart from the oil holes being somewhat misaligned
If theres the modified ball and spring setup fitted, which has the ball seating on the back of the pump
the gasket can interfere with the ball seating properly 
Wet sumping is then inevitable 
These are the reasons I make my own oil pump gaskets, individual to each crankcase, as the oil holes can vary a bit!!
All this was learned the hard way 

HTH
John O R

[manosound]

John,

Thank you. My apologies for not checking the part number (they don't mention the model) before jumping to conclusions. Even if it had been perfect for length and hole diameters, I would not have guessed that the placement of the oil holes would vary. However, now that I think about it, I suppose the holes are too close together to be drilled all at once with a multi-spindle drill head and a fixture carrying all the drill bushings.

In case anyone bought one of these (the gasket in question, that is) after I posted and before John posted, it could be on me, less postage. Send a PM.

Richard L.

[chaterlea25]

Hi Richard
The SRM gasket will work provided care is taken as I already described!
I am probably (I am) an exceptionally fussy Bas***d
I just hate having to go back into an engine to rectify silly problems that can be avoided with some extra
attention to detail during the build
Near enough is never good enough for me

Regards
John O R

[dpaddock]

Page 93 of Bacon's Twins book reveals why the round washer should be used. For pre-unit twins, the oil pump face and the stud face are not co-planar.

David

[shabashow]

Thanks David,

I knew there was a logical reason for me to fabriacte a suitably thick (thin, really) washer, apart from not being able to source the proper item at the time.

John

[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.