1952 oil pump

[anjimehra]

G'day Anji.
I haven't actually done that test. My guesstamate at a fast idle with 25/50 oil cold, would be around the 60 to 70 psi. Hot that would drop to about 15 to 20 psi and should get to 50 psi by 2500 rpm.
Please post your findings either good or not so good. I'll try to run a test soon.
Cheers

Hi Muskrat
Thanks. Will do the test on rhe weekend & revert. By the way, I stripped the rocker box, timing side to try & eliminate the soung ( track I put up ) but no luck, Any ideas.

[anjimehra]

When I worked for a shop & Dealership some years back (We worked on all kinds of classic bikes but were also a dealership for new Enfields and Urals) we had a test station to proof and test oil pumps.  It was surprising what can result. I thought the original Enfield oil pumps were a joke and was very pleased that starting with the Electra models they went to a real oil pump which I believe helped immensely.

  I made up one for Triumph twin engines and loaned it out for a vintage bike meet and someone stole it, have not made a new one yet.    I was thinking that with a number of BSAs i own, both preunit and unit models and the dodgy reputation that BSA pumps have that it might be a worthwhile project to make a test rig for BSA pumps that can accommodate a variety of pumps.  Might be a good off season project.  Ill post pix of my alternator and stator test rig as well, I am expanding it to test coils, and regulator/rectifiers
Thanks Sluggo

But there is a number of people who have done the same,. This article is quite interesting... I have a 1962 Matchless G80CS as well, and came across this article some time ago and thought it was worthwhile.  The oil pumps for later versions are the same as many Norton models so there is a cross over..

See: http://centralcoastclassicmc.com/NortonOilPumps.htm

Noc has a thing or 2 to say on the topic: http://www.nortonownersclub.org/support/technical-support-common/oil-pump-repair

Not related to BSA, but a wealth of knowledge and excellent tech materials posted by Fred & Ella up North of me in Seattle.  (Been a real asset to the community)
See: http://www.oldbritts.com/ob_tech.html

DynoDave also does BSAs,, but has written a wealth of info on a wide variety of topics, mostly related to Nortons as we all know,,, they need all the help they can get. 
But he has posted on a variety of forums the wide disparity of performance in rotary style oil pumps (Usually Norton) but the same design applies to BSA.  He has written some posts on this as well on AccessNorton and INOA about how BAD some pumps are and cautions anyone to test your pumps. Never assume.  The material he has posted has made me a believer.  You can troll around forums looking for his postings but here is his own main website.

See: http://atlanticgreen.com/norton.htm
See: http://atlanticgreen.com/bsamain.htm

I do have a couple cast iron pumps for the 1971-73 Unit twins and a B50 Single and I really like those, Thats what BSA Should have made all along.  But any pump can be improved.  Personally I am a BIG fan of a liquid filled oil pressure gauge and I tend to fit one to any of my bikes I keep for myself.  I am not certain yet how to plumb them to a preunit A10 but I will be doing so at some point.

I firmly believe it makes you a better owner and operator, Cold pressure can be shockingly high and it encourages you to properly warm up your mount, as well as prevented a few catastrophes.  Ill spare you the tales as the examples I have are NON-BSA but the experiences compel me to fit a gauge to anything I get my hands on.

I have a number of BSA service bulletins and its amusing how they decided to eliminate the idiot warning lights on later unit model BSAs because they alarmed the owners and resulted in more service warranty claims.  But my take-away from that is that Ignorance is NOT Bliss!

[anjimehra]

Not seen a figure for A7 or A10 but BSA did publish one for the A65, page 2 of that bulletin attached.

Thanks Julian

[anjimehra]

G'day Anji.
Just did a test on my 51 A7 (I wish I hadn't, rebuild will be sooner rather than later) and 57 A10 (recent rebuild). I plugged the blow off holes with blind rivets in the main body and drilled & tapped the end cap to take the gauge fittings.
  The A7 was very worrying (it's not fitted with a full time gauge like the A10). I know the main bush is worn but it must be phu(ked. At best it might have shown 5 psi at fast idle and maybe 10 psi with revs  .
  Then before I put the same setup on the A10 I started it for a minute to get the oil through it, 55 psi at fast idle. I then changed it over to the test rig. Strange that at the same fast idle (1500 rpm) it only showed 25 psi  . I then took her up to 4000 rpm (not wanting to rev a cold motor with forged pistons) and saw 90 psi on the gauge. It's fitted with the roller conversion and end feed to the crank so there's no loss through the bush.
  Now that my A7 is a lot sicker than I thought she'll be up for a rebuild over the next few months (after I move house), and she'll be getting a full time oil gauge. Lucky I did the test, she could have thrown a leg out of bed.
  Let us know your results.
Cheers

Hi Musky.
Wish you luck with the A7. Am sorry that I had to be the reason for the strip down !!!

[anjimehra]

G'day Anji.
Just did a test on my 51 A7 (I wish I hadn't, rebuild will be sooner rather than later) and 57 A10 (recent rebuild). I plugged the blow off holes with blind rivets in the main body and drilled & tapped the end cap to take the gauge fittings.
  The A7 was very worrying (it's not fitted with a full time gauge like the A10). I know the main bush is worn but it must be phu(ked. At best it might have shown 5 psi at fast idle and maybe 10 psi with revs  .
  Then before I put the same setup on the A10 I started it for a minute to get the oil through it, 55 psi at fast idle. I then changed it over to the test rig. Strange that at the same fast idle (1500 rpm) it only showed 25 psi  . I then took her up to 4000 rpm (not wanting to rev a cold motor with forged pistons) and saw 90 psi on the gauge. It's fitted with the roller conversion and end feed to the crank so there's no loss through the bush.
  Now that my A7 is a lot sicker than I thought she'll be up for a rebuild over the next few months (after I move house), and she'll be getting a full time oil gauge. Lucky I did the test, she could have thrown a leg out of bed.
  Let us know your results.
Cheers

Another stupid question Muskrat. Cant remember how the oil galleries are drilled in the inner cover, but does the oil go first to the PRV & then the big ends & mains or does it go directly to the crank
If I remember correctly, the camshaft & timing gears get lubricated via the prv

[muskrat]

G'day Anji.
The oil goes from the pump to the main bush then into the shaft and big ends. From the bush there is a drilling that feeds the prv. Once pressure has risen to the prv blow off the oil goes to the cam and timing gears.
How did your test go?
Cheers

[JulianS]

Diagram from the BSA patent on lubrication showing the drillings in the crankcase.

[anjimehra]

G'day Anji.
Just did a test on my 51 A7 (I wish I hadn't, rebuild will be sooner rather than later) and 57 A10 (recent rebuild). I plugged the blow off holes with blind rivets in the main body and drilled & tapped the end cap to take the gauge fittings.
  The A7 was very worrying (it's not fitted with a full time gauge like the A10). I know the main bush is worn but it must be phu(ked. At best it might have shown 5 psi at fast idle and maybe 10 psi with revs  .
  Then before I put the same setup on the A10 I started it for a minute to get the oil through it, 55 psi at fast idle. I then changed it over to the test rig. Strange that at the same fast idle (1500 rpm) it only showed 25 psi  . I then took her up to 4000 rpm (not wanting to rev a cold motor with forged pistons) and saw 90 psi on the gauge. It's fitted with the roller conversion and end feed to the crank so there's no loss through the bush.
  Now that my A7 is a lot sicker than I thought she'll be up for a rebuild over the next few months (after I move house), and she'll be getting a full time oil gauge. Lucky I did the test, she could have thrown a leg out of bed.
  Let us know your results.
Cheers

Hi Muskrat
Finally got the time to work on the A 7. Fitted the gauge & on a cold engine got 40 psi on fast idle. Does that sound correct ? Still got the noise from timing gear. Could it be that tha prv ball is not lifting to allow oil to pass to camshaft. Tried everything else
Take care
Anji
Musky, do you know where I can get some info on a 1921 sunbeam Iam restoring. Marston club has been very helpful but need more detailed info. Thanks

[anjimehra]

Diagram from the BSA patent on lubrication showing the drillings in the crankcase.

Thanks Julian

[chaterlea25]

Hi Anji,
I don't believe the PRV will send oil to the cam with only 40 psi
I seem to remember 55/60ps is needed to open the PRV
(another test rig needed???)

John

[muskrat]

G'day Anji.
As John said the PRV won't be opening at that pressure. The pressure will rise with revs to the point the PRV opens, usually 50-55Lb.
Sorry I can't help with the Sunbeam (all cloudy here  ).
Cheers

[ellis]

Hi anji, looks like a new pump is needed to up the oil pressure.   

ELLIS

[anjimehra]

Hi Anji,
I don't believe the PRV will send oil to the cam with only 40 psi
I seem to remember 55/60ps is needed to open the PRV
(another test rig needed???)

John

Thanks John. Will start the hunt for a pump.

[anjimehra]

G'day Anji.
As John said the PRV won't be opening at that pressure. The pressure will rise with revs to the point the PRV opens, usually 50-55Lb.
Sorry I can't help with the Sunbeam (all cloudy here  ).
Cheers

Hi Musky
Another question. Does the oil pump register 55 psi even when engine is hot & running at say 1/4 throttle or less ( in traffic ). If not then how does the cam get lubricated ?
Take care
Anji

[anjimehra]

Hi anji, looks like a new pump is needed to up the oil pressure.   

ELLIS

Thanks Ellis. Difficult to find here in India. Will start the process

Anji