The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Steverat on 21.12. 2018 19:11

Title: SRM oil pumps?
Post by: Steverat on 21.12. 2018 19:11
I’m at the point in the rebuild where the pump can go back on. I think the old one is okay though it is a bit stiff to turn manually - just pushing the drive pinion around withe the ball of the thumb Is probably not significant torque.

Anyway, there is a lot of new stuff in the engine so I’m wondering whether a better oil pump would be a good idea. SRM have a strong reputation so I guess their pump is good- but is the benefit worth the significant outlay? Would I notice anything? How does the pressure and flow rate compare with a standard BSA pump?

Thanks for your data and thoughts....
Title: Re: SRM oil pumps?
Post by: ellis on 21.12. 2018 19:27
No question about it SRM pump is the way to go. Bet you wouldn't like an old heart in your body.

ELLIS
Title: Re: SRM oil pumps?
Post by: muskrat on 21.12. 2018 19:30
G'day Steve.
I can't help with a comparo but all that get one love it. I too would dearly love one too but can't justify 2 weeks wages. I refurb mine anytime I have the motor down. Just by lapping the marks out of the end plate and extension housing. Mark everything on disassembly so it all goes back in exactly as it was. tightening the screws little by little whist turning the worm. If right it will be firm to turn but no tight spots. Both mine are the original pumps and both can pump well over 80psi.
Cheers
Title: Re: SRM oil pumps?
Post by: kiwipom on 21.12. 2018 20:48
hi guys, in my opinion putting an S.R.M. oil pump is insurance, you do all that work with new parts here and there so you dont want risk destroying everything by leaving the most important part to chance. I replaced mine as not being confidant of my own engineering to resurrect an old important part, but each to their own.
 Putting an oil pressure gauge in the system will let you know what is going on if you decide to keep the original pump, cheers   
Title: Re: SRM oil pumps?
Post by: JulianS on 21.12. 2018 21:02
No comparison between a new SRM pump and an old mazac bodied one.

SRM miles better, larger feed and scavenge gears and body does not distort, I think most mazac pumps have distorted bodies with distorted oil chambers which is why they are stiff or lumpy to turn manually.

Mine been in use 9 years works fine does not wet sump. Well worth the money
Title: Re: SRM oil pumps?
Post by: trevinoz on 21.12. 2018 21:31
Just a comment on the SRM pump as to whether it is effective in reducing or stopping wet sumping.
A friend recently restored a bike which was wet sumping.
He was advised to fit an SRM pump to the engine, which had been reconditioned, to stop the problem.
Pump fitted but the engine still wet sumps.
Obviously the check ball was not reseated during the overhaul but the point is an SRM pump will still pass oil, being a gear pump.
Title: Re: SRM oil pumps?
Post by: Rex on 22.12. 2018 09:21
If the engine didn't have an oil pump then I would have fitted an SRM one, but I wouldn't spring for an SRM unit if the old pump was useable (even with work) which it was.
Given the use most old A rangers will ever have, and the inherent reliability of the pumps an old original pump is more than adequate.
Title: Re: SRM oil pumps?
Post by: orabanda on 22.12. 2018 11:18
Over the last 30 years I have accumulated a few A10's.

I have had two of the original (Mazak) housings fail (crack and break away) in the thinner drive spindle area.

Others have shown signs of the metal crumbling away.

Not surprising that a 70 year old material,that was specified more for cost saving, than metallurgical quality (ie material was cheap), suffers fatigue failure.

I work in the fluid power industry; the only application of this material in a gear pump I have ever seen, is by now defunct manufacturers of British motorcycles.

All of my machines have a replacement high quality pump: some SRM, some cast iron).

Richard

Title: Re: SRM oil pumps?
Post by: chaterlea25 on 22.12. 2018 11:47
Hi All,
The old mazac pump bodies can also go porus *ex*
I have told the story before on similar threads about how a porus pump body wrecked my brothers SR
I also have seen so called rebuilt pumps fail to perform on SRM's test rig

(Just a happy New pump user)
John
Title: Re: SRM oil pumps?
Post by: RichardL on 22.12. 2018 15:09
Over the last 30 years I have accumulated a few A10's.

A few?  *eek* ;) *smile*

Richard L.
Title: Re: SRM oil pumps?
Post by: scotty on 22.12. 2018 20:15
+1 SRM oil pump for me

Does not stop wet sumping in my case but I live with it

S
Title: Re: SRM oil pumps?
Post by: beezermacc on 22.12. 2018 23:06
Just fitted a Wassell cast iron pump to my newly built bike. The flow rate looks the same as the previous standard pump but it has cured the wet sumping. The Wassell pump does not come with the crankshaft worm whereas the SRM pump does.
Title: Re: SRM oil pumps?
Post by: chaterlea25 on 23.12. 2018 17:25
Hi All,
Thinking back, some time ago, 2010 ??
I rebuilt a customer A10, I had the anti drain ball valve modded to seat against the rear of the pump when getting SRM to fit a new bush and grind the main and B/E journals
They rebuilt the standard pump at the same time
The bike wet sumped after the rebuild  *sad2* so the owner asked me to fit a new SRM pump
That cured the wet sumping  *smile*

John
Title: Re: SRM oil pumps?
Post by: beezermacc on 23.12. 2018 18:43
Hi All,
Thinking back, some time ago, 2010 ??
I rebuilt a customer A10, I had the anti drain ball valve modded to seat against the rear of the pump when getting SRM to fit a new bush and grind the main and B/E journals
They rebuilt the standard pump at the same time
The bike wet sumped after the rebuild  *sad2* so the owner asked me to fit a new SRM pump
That cured the wet sumping  *smile*

John

A mate of mine bought a bike which had an SRM engine fitted. My mate asked me to have a look at it after it seized (twice actually). We stripped the top end and found no problems apart from seizure marks on the pistons so just rebuilt it again after cleaning the pistons up. However, on checking the oil return on startup I was alarmed to see virtually no oil returning to the tank. The bike had an original pump so I blamed that and we swapped it - no difference, still very little oil return. I'd noticed the ball and spring on the back of the pump and wondered if this was the cause of the problem so, off with the pump, remove ball and spring.... hey presto! A gusher of an oil return. I can only assume that the ball was compressing the spring completely thereby causing a blockage in the oilway. Whatever the diagnosis the modification had cut the oil off.
Title: Re: SRM oil pumps?
Post by: chaterlea25 on 23.12. 2018 19:37
Hi Beezermacc,
I cannot answer that ???
The ball needs to be 1/4in. it sits in a 5/16in. drilling ( I posted some photos on another thread recently of the setup)
If the wrong size ball was fitted it could cause a problem *????*

I have my own SR with the SRM setup on it with in excess of 25k miles without issues
All the other A series bikes that I have rebuilt with the modification have run trouble free

John
Title: Re: SRM oil pumps?
Post by: BSA_54A10 on 24.12. 2018 23:02
Over the last 30 years I have accumulated a few A10's.

I have had two of the original (Mazak) housings fail (crack and break away) in the thinner drive spindle area.

Others have shown signs of the metal crumbling away.

Not surprising that a 70 year old material,that was specified more for cost saving, than metallurgical quality (ie material was cheap), suffers fatigue failure.

I work in the fluid power industry; the only application of this material in a gear pump I have ever seen, is by now defunct manufacturers of British motorcycles.

All of my machines have a replacement high quality pump: some SRM, some cast iron).

Richard
Total & utter crap.
The zinc based alloys used were metallurgically  a very sound decision.
The EXACT SAME ALLOY has been used for decades in carbs, injection pumps & turbos.
Even today the tonnage of Zn based alloys is nearly 2/3 the tonnage of Aluminium/\.
Mazark by the way is a trade name for around 20 different zinc based casting alloys, and not a specific metal.
It is the perfect material for pressure tight cast to size high precision castings and is still used for that purpose today.

The simple fact is BSA did not factor in a 70 year service life. THIS IS NOT A MATERIALS FAILURE .
Your A 10's had a 90 day warranty in the USA and 12 months in Australia so the minimum service life of any part was the 12 month warranty period.

BSA knew what the average service life of a motorcycle was back then ( around 25 years from memory ) and so they designed the bikes to go that distance.
Remember that in the day it was new rings & big ends at 30,000 miles for BSA's but 50,000 miles for Triumphs because they used better slipper materials.
However no one puts Schit on the slipper material.

And by the way, MAZARK was not cheap. It was a branded alloy so BSA had to pay royaltities for using it.
It was however easier to machine and suffered substantially fewer machining failures than making them from cast iron.
So if you consider using a material that had a better than 90% acceptance rate over one that had a 30% quality failure rate then yes it was a cheaper option than the cast iron pump.

Oh and by the way just about every automotive oil pump, the one in your car right now is made from the same
DEFECTIVE CHEAP & METALLURGICALLY UNSUITABLE MATERIAL
so you better go out right now rip it out and toss it  in the scrap bin.
Title: Re: SRM oil pumps?
Post by: Greybeard on 24.12. 2018 23:33
Whispers: happy Christmas!
Title: Re: SRM oil pumps?
Post by: orabanda on 25.12. 2018 00:57
Thanks Trevor,
All of your points appreciated; I have learnt a lot.
Merry Christmas
Richard
Title: Re: SRM oil pumps?
Post by: Colsbeeza on 25.12. 2018 01:22
What a great discussion. I recently dismantled my original Marzak oil pump, and found it a bit stiff, not being able to rotate it by thumb. I found the main shaft tight due probably to corrosion due to standing about for 20+ years. I probably did not assemble it properly 25 years ago.
In the process, I dropped the gears and of course had no idea where each had been fitted.
I inspected the casting, and found no defects, polished the end plate with oiled 1200 Wet-n-dry on a glass plate, and re-assembled it. On tightening the screws, the gears locked up fairly tight. It took several iterations of the gears to find the best fit to reduce friction. Finally I found a combination which worked well.
The pump works well, gives 60psi cold and 40psi hot.
I may eventually get a new pump, but until I get trouble, will stick to the original.
Col
Title: Re: SRM oil pumps?
Post by: BSA_54A10 on 25.12. 2018 01:45
And a merry one to you.

Sorry to jump off the pan handle but I was a metallurgist and even taught it for a long while after I left the industry.
Way back , illiterate wafes got a job as a copy runner in a printing works.
They ran around all day clutching galleys of type in their grubby hands to hopefully be delivered to the correct copy reader then eventually back to the sub editors then to the comp shop to be pasted tgethe to make a page then back down to the foundry to be set in metal.
Eventually these urchins got to do some menial writing then eventually reporting and finally graduated to journalist if they could manage to convert the bumf the factories supplied into words that the factories approved of and Joe Public found plausable.

From the pens of these totally engineering illiterate came all sorts or rubbish, like picking up on the term "Pot Metal".
Pot metal was a foundry slang term applied to everything that was melted in a crucible rather than in a "real " furnace like a blast furnace, cupola or rotary hearth.
Naturally all of these were superiour to melting in a pot so by vitrue of this all "pot metals " must be inferiour and there fore make inferiour parts.

There is a big difference between selecting the best metal and the right metal.
Rolls Royce used the best metals and were perpetually on the verge of and in bankruptcy .
Ford chose the right metal and made a fortune.
Pilgrim pumps were piston pumps and long considered the state of the art in pumps.
They were made from cast iron because the pistons needed a fine hard & strong surface to run against.
Some were made from bronze but initally all were fitted outside the engine and plumbed in.
Thus any pump not made from cast iron or bronze had to be inferiour, to a 4 year olds understanding.
Thus it went into print and got repeated & repeated till by the face book principle it has to be true.

In a gear pump. the actual pumping is done by the gears so what is important is the fit of the gears into each other.
And yes excessive side clearence will allow the pump to leak, but that is not the critical part, the gears are.
The body just needs to maintain the position of the gears relative to each other and be pressure tight so must be rigid & be able to be cast without porosity defects.
Zn is a bearing metal ( yes others are better ) and is pressure tight through very thin wall thicknesses so fits the bill quite well.
IT also has an expansion co-efficient close to aluminium and can be made to almost exactly replicate that of the Al-Si used for the crankcase casting.
Thus is does not leak, will warp & contort to comply with crankcase movements, is easy to machine WITH THE PRODUCTION TOOLING OF THE DAY and takes a fine finish.

Also we have to remember that it was deigned to be used with strait 30 or 40 oils, not multigrade oil which is full of aditives some of which can attack the pump chemically.

Even in the day of computer controlled carbide tooling that is accurate to .000001", SRM chose to machine their poump from extruded alloy to get the pressure tightness & rigidity necessary to work reliabily.
Title: Re: SRM oil pumps?
Post by: bsa-bill on 25.12. 2018 10:09
Well said Trevor

I've no doubt SRM pumps are everything  they are said to be, but hey the majority of us are riding around on 70 + year old machines designed for commuting with much original stuff in them, my high tech 1/lt 3 pot fiesta is great for commuting also but I  doubt it will be 70 odd years from now.

Merry  Christmas all
Title: Re: SRM oil pumps?
Post by: Rex on 25.12. 2018 11:46
Trevor, what's your take on BSA original pumps stiffening up when unused (all models) and that stiffening being attributed to the Mazak "swelling"?
Title: Re: SRM oil pumps?
Post by: ellis on 25.12. 2018 13:53
BSA_54A10

Always send your copy to the proof reader before it goes to print so that any spelling mistakes are corrected.

ELLIS  ex stereotyper.    *beer* 
Title: Re: SRM oil pumps?
Post by: BSA_54A10 on 25.12. 2018 21:55
Trevor, what's your take on BSA original pumps stiffening up when unused (all models) and that stiffening being attributed to the Mazak "swelling"?

My initial thoughts would be bollocks.
Oxide growth certainly but swelling of the alloy at room temperature not top on the list of possibilities .
Zinc based alloys do not adsorb much hydrogen from the atmosphere as aluminium alloys will.
And even if they did, energy has to be applied to allow the trapped gas atoms to travel through the lattice structure then bump into each other and for a hydrogen molecule.
Then you need thousands of these events to put enough strain on the lattice to cause the layers of atoms to slide over each other and cause the item to grow.

OTOH it does not take any energy for the surface of the metal to oxadize, in fact it takes energy to prevent this happening.
The corrosion product of zinc based castings can have a variety of structures depending upon how many water molecules get included.
If there is little water the corrosion layer is translucient and as such quite hard to see with the naked eye .
You do not see the oxide layers that have formed on your carb body & slide on concentric carbs but it is sufficient to lock the slide in place then rip lumps of zinc off the surface of either the carb or slide. The process is called stiction ( joining together ) & gauling ( ripping surface atoms off )
Now this happens between a body & slide where the space is around .005".
It will also happen around the hole in a pump body where the running clearance is in the order of 0.0005"

The number 2 culprit would be plain old slump.
Nothing that we think is solid is actually solid and over time nothing greater than gravity will cause everything to go "pear shaped".
It is just some, like glass & lead will do it faster than others like steel & titanium but they all do it
So if stored for long enough not properly supported I would expect pump bodies to distort over time.
Even the Platinum-Irridium bar which used to be the standard meter distorts over time which is why it got replaced with an atomic measurement, and even that has found not to be as stable as we had hoped for so was reciently upgraded again.
Title: Re: SRM oil pumps?
Post by: BSA_54A10 on 25.12. 2018 22:05
BSA_54A10

Always send your copy to the proof reader before it goes to print so that any spelling mistakes are corrected.

ELLIS  ex stereotyper.    *beer*
Ellis.
I was a 75wpm typist at 60%.
Spell checkers slow this down massively particularly when they seem to be getting more & more American every day.
I am dyslexic so reading for fun was & is a painful process.
Then having spent 20 years training in science /engineering where you have to read for content, you skim & scan rather than read words thus the more educated I got the worse my spelling got.
However you are more than welcome to proof & correct any galley of mine should you feel inclined to do so.
If it is any comfort to you, the humanities students used to experiment on students to see if there were similarities in eye movement, reading speeds, short & long term retention & spelling within disciplines.
My spelling was smack in the middle for engineering students and in the lower 20% or science students
Science & Engineering students were way above humanities students in speed, retention & comprehension
Title: Re: SRM oil pumps?
Post by: Colsbeeza on 25.12. 2018 22:31
As regards swelling, I mentioned earlier that the main gear shaft was tight in its fit through the alloy. I measured the shaft diameter and ran the appropriate drill gently through the alloy casing. The material removed looked like corrosion to me, not swelling of the alloy. This pump had not been used for 25+years, but was installed.
I also forgot to mention that I was not happy with the seal of the end plate - I could see leakage happening, so used the slightest smear of red hermetite, being well aware that I did not want any sealant in the oilways. Sofar so good!
Cheers Colin
Title: Re: SRM oil pumps?
Post by: berger on 26.12. 2018 01:20
hey trevor some very interesting stuff on this metals subject and breathing as well, I was gifted some plastic packed grease nipples years ago which were for use on aircraft-RAF old stock. they had use by dates on each pack , I often wondered and still do as to why a grease nipple has to have a use by date?
Title: Re: SRM oil pumps?
Post by: BSA_54A10 on 26.12. 2018 03:41
Everything that goes into aircraft has a use by date.
There is a small spring behind the ball which like a valve spring will eventually loose tension.
Title: Re: SRM oil pumps?
Post by: ellis on 26.12. 2018 12:24
BSA_54A10

That was just an observation and not a criticism. Please accept my apology i didn't mean to offend.

Merry Christmas to you all.

ELLIS   
Title: Re: SRM oil pumps?
Post by: berger on 26.12. 2018 14:51
cheers trevor never thought of that, everything has a reason . it struck me as being odd but now explained *beer*
Title: Re: SRM oil pumps?
Post by: BSA_54A10 on 26.12. 2018 22:07
BSA_54A10

That was just an observation and not a criticism. Please accept my apology i didn't mean to offend.

Merry Christmas to you all.

ELLIS   

Ellis.,
I ride BSA's so
1) you could not insult me if you tried
2) no offense is ever taken at anything said to my face
3) I have a sense of humour ( note the spell chequer won't accept the u in humor ) that includes self deprecation in spades.

So no worries.
The offer to edit my galleys still stands.
I have not had the luxury of a sub editor since I stopped writing for Reed and that was in the 90's

On the funny side.
Directly after school I went into the SMH proof readers test with a bunch of mates, as you did in the days when people were more important than property.
At the start we were told only those with a 100% score would get one of the 30 positions on offer.
Stage 1 was a strait spelling test, you got a new word every 15 seconds
about 1/2 the applicants had left after the first 10 words
By the time the whole 100 words was done there were about 50 of the 300 odd applicants left.
Then we went to the observation section where we were all given a galley about a meter long in a variety of font sizes printed in 1/2 tone ( draft ) on slightly yellowed print stock.
we had to mark up , but not correct , all of the spelling & grammar errors with a blunt purple pencil.
2 minutes were allowed for this and by pens down there were only 9 people left , including me and we were all offered positions.

Apparently speed & self confidence were more important that actual accuracy.
Some where in the box of self stuff is the letter of acceptance as a copy proof reader, I kept it for the fun of it.
And yes, Russ got the job and he stayed with the SMH for 40 years .
Title: Re: SRM oil pumps?
Post by: ellis on 27.12. 2018 03:08
Hi Trevor.

I must confess my printing qualifications pales into insignificance after reading what you have done. I will give you a wave as i pass over Australia on the 25th of January on my way to Auckland.

Cheers

ELLIS
Title: Re: SRM oil pumps?
Post by: muskrat on 27.12. 2018 04:02
Good one Trevor.
You said "left", meaning they thought they were out and left of their own accord. You and 8 others bluffed your way through. Right?
Cheers
Title: Re: SRM oil pumps?
Post by: BSA_54A10 on 27.12. 2018 05:46
Yep,
got up and walked out.
I was going to UNSW the following year and had a full time night shift + 2 weekend jobs so I did not need another and the starting pay rate was not real good.
When Russ told me what they had to do I could understand the need for speed.
No time to check a dictionary , you really had to inspect the individual galleys as they were presented before the type was set in metal.
The subbies had to retype the entire galley then send it off to the print shop.
No time for a second reading except for the front few pages of each section.
And in those days the Herald was a broadsheet and a very thick one . There were up to 6 time editions plus local & international variations
Title: Re: SRM oil pumps?
Post by: chaterlea25 on 28.12. 2018 23:39
Hi All,
I came across this photo of a BSA single oil pump (on ebay)
It shows how the mazac alloy can rot and crumble away  *sad2*

John
Title: Re: SRM oil pumps?
Post by: Colsbeeza on 29.12. 2018 01:49
Hi John, Judging by the appearance of the steel fittings, it has lain outside in the weather for about 40 years.
Colin
Title: Re: SRM oil pumps?
Post by: Steverat on 29.12. 2018 08:54
Well my oil pump looks perfect in comparison. It’s been quite a discussion, I think I’ll keep the old pump for the time being. Thanks for all your relevant views
Steve
Title: Re: SRM oil pumps?
Post by: kiwipom on 30.12. 2018 01:57
Well my oil pump looks perfect in comparison. It’s been quite a discussion, I think I’ll keep the old pump for the time being. Thanks for all your relevant views
Steve
Or at least until the engine seizes up, cheers
Title: Re: SRM oil pumps?
Post by: Steverat on 30.12. 2018 07:21
Well, if I can put it on straight, and it returns oil to the tank, likelyhood is that it is supplying it to the engine too. And Josef is not planning on doing many miles with the bike, and certainly not at the limits of its performance. I have discussed your concerns  with him, and we decided on balance he'd rather spend the £300 elsewhere.
Title: Re: SRM oil pumps?
Post by: Greybeard on 30.12. 2018 09:39
Don't forget the thin fibre washer under the nose of the pump.
Title: Re: SRM oil pumps?
Post by: chaterlea25 on 30.12. 2018 15:16
Hi All,
The fibre washer fitment can be the cause of all sorts of problems *eek*
If a new or prefaced pump is being fitted
The washer should be the same thickness as the gasket, but even so the fibre is much harder than the gasket paper
Resulting in strain/ more distortion of the pump body, and more leakage *ex* *ex*
The gaskets in the usually supplied kits are a poor fit at best *sad2*
I make my own gaskets to closely match the oilway, andwith an extension to match up with the third fastening
So the thickness is equal across the joint

John
Title: Re: SRM oil pumps?
Post by: JulianS on 30.12. 2018 16:26
I agree re the gaskets/fibre washer.

I use an SRM gasket prefering not to make my own. Fits perfectly and oil holes line up and are the right size.

The photo shows 3 different gaskets;

Top left taken from a new old stock BSA made gasket set. It fits and holes line up.

Bottom the SRM product, the large hole being for the ball bearing seating against rear of the pump.

Top right is a real worry. Being sold by a number of ebay sellers. Oil holes too small and dont line up properly resulting in reduced oil flow and risking your engine.
Title: Re: SRM oil pumps?
Post by: Steverat on 30.12. 2018 21:22
I agree re the gaskets/fibre washer.

I use an SRM gasket prefering not to make my own. Fits perfectly and oil holes line up and are the right size.

The photo shows 3 different gaskets;

Top left taken from a new old stock BSA made gasket set. It fits and holes line up.

Bottom the SRM product, the large hole being for the ball bearing seating against rear of the pump.

Top right is a real worry. Being sold by a number of ebay sellers. Oil holes too small and dont line up properly resulting in reduced oil flow and risking your engine.

Went straight to SRM webshop and bought one, thanks for the tip. ;D
Title: Re: SRM oil pumps?
Post by: Steverat on 03.01. 2019 13:43
Tried to fit the BSA pump only to find the housing so distorted I had to counterbore the casting to get it on over the studs. The joint face is warped, not sure if the nice SRM gasket can take all that up. Also the pump (as previously mentioned) almost too stiff to turn by hand. So I have asked Josef for clearance to buy an SRM. Just look at how the casing has squashed down.
Title: Re: SRM oil pumps?
Post by: Swarfcut on 03.01. 2019 16:42
Steve,
     If you want to play with your original pump, the way that works for me is to reassemble  the gears one at a time selectively adding gears and checking for binding. Sometimes moving the gears to ensure the high  spots never meet is all you need. I drive the gears with a slotted rod, not the drive spindle gear. I tighten the four bolts gently to make sure the gears still turn OK.  Then add the proper drive spindle gear...if it is tight in parts, take it out, rotate half a turn and try again. If all is reasonable, finally tighten the  bolts, turning the drive gear and flexing the body and nose casting as you go, tightening and turning to check for binding. You should end up with a reasonable pump.  The pump can be hard to fit if the mounting studs are slightly bent or bowed.

  Your pump body is far better than most at this age, so don't be to hasty in scrapping it. An alternative for you is to trade it against a recon pump, available from several UK Suppliers.
 
 Swarfy.
Title: Re: SRM oil pumps?
Post by: JulianS on 03.01. 2019 18:28
When the body distorts the oil chambers can distort causing the tight spots and spots with greater than designed clearance. Tight is some places and worn or worn out in others.
Title: Re: SRM oil pumps?
Post by: Rex on 03.01. 2019 18:33
Don't know enough about A range pumps, but on BSA singles the advice is to always remove and strip the oil pump when the bike hasn't been run for a while, as it becomes stiff to rotate, and if it's stiff enough it'll strip the pump drive PDQ consequently leading to a seized engine.
Title: Re: SRM oil pumps?
Post by: chaterlea25 on 03.01. 2019 20:12
Hi Steverat,
Quote
if I can put it on straight, and it returns oil to the tank, likelyhood is that it is supplying it to the engine too

As the song said "It ain't necessarily so"
  *warn*

If the pump is leaking either through the end plate/ gasket/ or porus body there will be little oil pressure to the big end's
The leaked oil will drain to the sump, as there is very little restriction on the return side it may appear that the oil circulation is "OK"

John
Title: Re: SRM oil pumps?
Post by: Steverat on 03.01. 2019 22:53
Yes I take your point. We decided on an SRM pump today, already ordered. After all the arguing back and forth I had lost confidence in. the obviously worn BSA pump and I just don’t have the time to play with it since Josef is coming for the finished bike in March.
Title: Re: SRM oil pumps?
Post by: Steverat on 05.01. 2019 16:46
SRM were quick, pump came this morning! Lovely looking item, very pleasingly packed with all the bits I might need. But I'm confused by the instruction sheet, it seems to be telling me to leave out the spring loaded ball. What do you think? I can't phone them for guidance since its the weekend but it would be nice not to have to wait for Monday. I've highlighted the relevant sentence in pink.
Title: Re: SRM oil pumps?
Post by: berger on 05.01. 2019 17:26
steverat if your bike engine has the spring and ball in the timing side crank case and the bronze main bearing ignore that bit because that is for converted A7s/10s
Title: Re: SRM oil pumps?
Post by: Swarfcut on 05.01. 2019 18:59
  Steve, before you fit that lovely new pump, prime it with oil and make sure it works. Also use a pressure oilcan on the oilway to the timing bush.  This will force oil to the big ends. You can also remove the PRV and make sure oil is flowing from the bush to the PRV.  Also worth removing the rear tappet cover and filling the pushrod tunnel with oil. This will drain down into the camshaft trough and overflow into the sump, ready for the scavenge side to start working immediately rather than running the return side of the pump dry until oil works its way down there. This way all the essential bearings and the camshaft and followers are well lubricated for the  first start up.



 Not long now.......

 Swarfy.
Title: Re: SRM oil pumps?
Post by: Steverat on 05.01. 2019 19:33
That’s sage advice many thanks
Title: Re: SRM oil pumps?
Post by: metalflake11 on 05.01. 2019 20:04
  Steve, before you fit that lovely new pump, prime it with oil and make sure it works. Also use a pressure oilcan on the oilway to the timing bush.  This will force oil to the big ends. You can also remove the PRV and make sure oil is flowing from the bush to the PRV.  Also worth removing the rear tappet cover and filling the pushrod tunnel with oil. This will drain down into the camshaft trough and overflow into the sump, ready for the scavenge side to start working immediately rather than running the return side of the pump dry until oil works its way down there. This way all the essential bearings and the camshaft and followers are well lubricated for the  first start up.



 Not long now.......

 Swarfy.

They are all tested on the bench before they leave S.R.M. You can take that to the bank, I've seen Gary Hearl doing it with my own eyes.

Every pump and P.R.V. every time!
Title: Re: SRM oil pumps? HELP!
Post by: Steverat on 06.01. 2019 15:46
steverat if your bike engine has the spring and ball in the timing side crank case and the bronze main bearing ignore that bit because that is for converted A7s/10s

Still confused I'm afraid, there's no way for me to fit spring and ball between the pump and the timing chest, I just tried with a 3/16" ball (diasappears into the pump) and a 1/4" ball ( won't go into the timing chest, prevents pump from bolting down onto the joint face). I have the standard bronze bush A10 engine, not converted. Do you (and SRM) mean that I don't need to fit spring and ball? The supply side hole into the engine has the same diameter (just over 3/16") as its mating bore in the pump, so there's no way that a ball on a spring in the timing chest could seat on the pump - if it goes into the timing chest, it goes into the pump too.

So do I leave out the spring and ball, or what am I missing?

Title: Re: SRM oil pumps?
Post by: Swarfcut on 06.01. 2019 16:21
Steve.... The standard set up for your crankcase is a non return ball valve at the bottom of the oilway from the pump output to the timing bush. This valve is supposed to prevent oil from the tank draining into the sump when the machine is not in use. If you gently push a matchstick or similar into the oilway you should feel the ball.....it will move in as you push and out again under the influence of the small return spring underneath as you let go.

   Because this valve is only accessed from inside the cases, the later similar A65 engine had a design change to enable the ball valve  to be easily serviced by simply removing the oil pump. The confusion you have is partly due to the poorly worded instruction leaflet from SRM and probable inclusion of  spurious parts to the oilpump pack, namely an extra ball and spring, to cover modified engines.

  If you still have the standard valve in situ you just need the pump and the gasket, making sure the gasket holes do not obstruct the oilways.  LEAVE THE EXTRA BALL AND SPRING OUT!

  If there is no ball valve already in place, then we may have to think again, but its an easy fix.

  Swarfy.

Title: Re: SRM oil pumps?
Post by: RDfella on 06.01. 2019 16:25
Steve, the standard, unmodified system has the spring and ball tucked away inside the crankcase. Can only get to it with a full engine strip. You may just feel the ball with a piece of wire if you poke it into the oil feed hole.
Title: Re: SRM oil pumps?
Post by: Steverat on 06.01. 2019 16:30
Thanks guys you are brilliant. *smile*
Straight back into the garage with matchstick in hand - yessss! Felt the internal ball valve.
Pump now on.