Oil pump query

[bevanclark]

Hi folks,
I have been experiencing repeated return pump failures with my 1950 VB. Despite doing all the things previously recommended by the various experts on this forum (draining, cleaning the tank, pump, lines and filters, blowing out lines, tapping the ball to reseat it etc...) it keeps happening. There is some small uneveness (I wouldn't say it is large enough to be described as pitting) around the return ball seat and the plunger has some mild scoring on the working part of the surface and signs of past corrosion further up.

When it is working, it returns oil strongly to the tank. Each time I have dismantled the pump after a return failure I have never found any gunge etc around the ball and seat, so I'm rather mistifyied why it should work so well, but then randomly stop.

I do have a couple more things to try before giving up and looking for a replacement pump - I've got some replacement 7/32" ball bearings (and have ordered new springs). I have just glued one ball to a drift, with the idea that I may be able to lap the seat with some Autosol or similar. Not sure if this is sensible/feasible.

Single spares do not have any serviceable plungers left and Draganfly can't even give me wild guess as to when their Hawker pumps may be available, so if I am to replace the pump, it looks like my only option is a Morgo pump. This company seems to have them in stock:
https://www.sealycycleservice.com/produ ... r-oil-pump

This seems a massive overkill for a side valve, but I'd be interested to know if this may be a good option, albeit an expensive one.

Any and all advice would be welcome !

Cheers,
Bevan

[Roger Gwynn]

Polishing the seats would be good, they look rather rough and polishing will show up high spots. They can be refaced using a drill bit but require careful setting up in a drill press. New balls and springs would be my first try, seat the balls using a drift on the balls grip the pump in the soft jaws/rag in the vice, use some packing under the pump to stop it moving as you hit the balls. These pumps will work for ages without problem and then all sorts of unfathomable problems. The plunger looks a bit nasty but unlikely to reduce pumping, as you say when it works it does so very well. When re-fitting the pump make sure that the sliding block is free to move and not trapped between plungers and nut. Check that the pick up pipe is secure in the crankcase, remove sump and give it a wiggle and a couple of gentle taps. Check for the additional washer around the pick up pipe where it pokes through from c/case to gear case. The pipe must be air tight or it won't pump, well actually it will but it will pump air not oil.

[Julian Murphy]

Could be a trick of the light in the photographs but the seats do not look wery equal all the way round, even if you have tapped a ball on them.

Good idea to bond a ball to a stick, and use solvol to lap the seats in.
Will probably take awhile. Have plenty of hot coffee available.

Be very exact in the cleaning up afterwards to remove all traces of solvol, it is an abrasive afterall.

On the plunger, I would be tempted to use a piece of well worn 1200 G or 1500 G with a lubricant (even water with a drop of washing up liquied in it to make it 'wet' the surface.

(I very rarely through out old wet and dry...the old well worn pices are perfect for this)

[bevanclark]

Thanks for the helpful replies.

It was very hard to photograph the seats; the feed one looks smooth under a magnifyng glass, but the return definitely does not, and there is a discolouration around the seat area, so I'll give polishing a go this morning. I had wondered about lightly dressing the return plunger, so will take another close look at that. As I had said, when it is working it pumps really well - with the sump off and a hose in a glass jar, it sucked around 50 ml of oil out in a few seconds and hurled it back into the tank. I did also blow as hard as I could with one end of the copper pipe blocked and could not detct any ait leak.

I'll fit new springs as soon as they arrive, but may as well try to polish the seat in the meantime.

Thanks again.
Cheers,
Bevan

[paul.jameson]

You might like to consider the factory option in Service Bulletin 125:

http://arielownersmcc.com/members_only/ ... %20125.pdf

[bevanclark]

Hi Paul,
I had seen the service bulletin #125 that details that modification. If I understood it correctly, it seemed as if it would be necessary to drill some way into the copper pipe to get sufficient depth to locate the spring, which made me a bit uncomfortable. But I guess it is the next option if new balls & springs and a polish don't do the trick.
Cheers, Bevan

ps Just re-read the service bulletin, and i think I did misunderstand - you drill out the return hole that leads to the tank, not the suction line from the sump - I think ???

[JohnnyBeckett]

hi, if it was me i would just get on to MORGO and get a mew pump a good oil pump is the heart of a engine, like your own heart if that is knackered so are you

[paul.jameson]

It is most definitely the return line to the tank which you drill out, not the suction pipe from the sump.

[bevanclark]

Thanks Paul, I'm new to Ariels so it is all a learning experience.

Johnny - I'd be tempted to buy a Morgo pump, but can't find one available anywhere - all sites I've checked so far say "out of stock"

[jannickz]

Hi Bevan,

I feel your pain on the repeated return pump failures with your 1950 VB. It's frustrating when everything seems right, but the problem persists. Here are some thoughts on your situation and potential solutions:

Gluing a bearing to a drift and lapping the seat with Autosol is a feasible approach, but proceed with caution. The key is to use a very fine abrasive and go slowly to avoid removing too much material and altering the seat's geometry. Consider using wet-sandpaper wrapped around the ball bearing from instead of Autosol for finer control. Start with a higher grit (around 500) and gradually move to a finer grit (around 1000) to achieve a smooth finish.

Mild scoring on the plunger might not be a significant issue if it's not deep or affecting the seal against the ball. However, significant corrosion further up could be impacting the plunger's movement and contributing to the intermittent failures. If possible, carefully polish the scored area with a fine abrasive cloth or stone to ensure smooth movement.

[admin 19/02/2024: edited to remove sneaky backlinks, this post is from a spamming bot - account now deleted]