The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: anjimehra on 28.01. 2017 13:32

Title: 1952 A7 oil to rocker box
Post by: anjimehra on 28.01. 2017 13:32
Hi guys
Just started up the basket case A 7 today & she fired up instantly & soon settled down to a steady fast tickover. One problem. Very little oil going into the rocker box, resulting in too much clatter. Rocker box dry. Closed the hole in the return pipe & a a little oil seeped out from the sides of the rockers. Tappets remained dry & no oil going down to the camshaft. Assuming holes in rocker shaft clear as newly assembled. To the best of my knowledge there should be a lot of oil spraying around in the rocker box. Any suggestions  Thanks
Anji

adm edit: title edited to reflect topic content
Title: Re: 1952 A7 oil to rocker box
Post by: stu.andrews on 28.01. 2017 14:57
No, there should not be a lot of oil up top as it will run down the valve guides & burn. A little oil should be up there so I would see if there is any restriction in the feed.
Title: Re: 1952 A7 oil to rocker box
Post by: muskrat on 28.01. 2017 18:24
G'day Anji.
As Stu said a lot of oil is no good but how much is just enough? I've never measured the oil flow to the rockers. I'll be doing a bit of work on my 51 A7 this week so will run a test.
Cheers
Title: Re: 1952 A7 oil to rocker box
Post by: Klaus on 28.01. 2017 19:10
My experience is another. There is a lot of oil coming out from the oilfeed banjo. Open the inspektion covers and you can seethe oil runimg down from the rocker spindels. The most oil is feed to the exhaust rockers were the oil is spreading out by running a few minute.
The cam is running in a tube filled with oil so the cam is well lubricated as the camfollowers too. Oil from the inlet rockers going down the push rods  to the top of the followers and through two holes back in the crankcase. So check the connection from the oilfeed junktion ift they is free off dirt.

cheers Klaus
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 29.01. 2017 06:33
My experience is another. There is a lot of oil coming out from the oilfeed banjo. Open the inspektion covers and you can seethe oil runimg down from the rocker spindels. The most oil is feed to the exhaust rockers were the oil is spreading out by running a few minute.
The cam is running in a tube filled with oil so the cam is well lubricated as the camfollowers too. Oil from the inlet rockers going down the push rods  to the top of the followers and through two holes back in the crankcase. So check the connection from the oilfeed junktion ift they is free off dirt.

cheers Klaus

Thanks Klaus. Have checked oil at banjos & it's getting there. Have also blocked the return hole in the oil tank & a little oil seeps out from the sides of the rockers but stops when I let oil flow back into tank. Because of this no oil reaching the camshaft & tappets. Engine newly reconditioned
Anji
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 29.01. 2017 06:40
G'day Anji.
As Stu said a lot of oil is no good but how much is just enough? I've never measured the oil flow to the rockers. I'll be doing a bit of work on my 51 A7 this week so will run a test.
Cheers

Hi Muskrat
Agreed, too much oil counter productive, but it's not even getting to the tappets & the camshaft is running dry as no oil is draining down via the pushrods tube. The rocker shaft oil galleries appear clear as oil seeps out of the sides of the rockers if I block the return hole in the tank. Totally foxed !!
Take care, Anji
Title: Re: 1952 A7 oil to rocker box
Post by: KiwiGF on 29.01. 2017 07:01
Have you checked there is plenty of oil returning to the the oil tank?

A proportion of the oil returned to the oil tank is bypassed to the rockers, by the action of a slight restriction placed in the return where it attaches to the oil tank, the restriction will hardly be affecting he return rate, as if needs be, the return side of the pump could reach the same psi as the feed side, in practice it doesn't, as there is very little restricting the oil flow back to the tank.

A rocker feed copper pipe with too small an I.d. Might slow the oil supply down?
Title: Re: 1952 A7 oil to rocker box
Post by: Rocket Racer on 29.01. 2017 07:10
keep in mind the camshaft runs in a bath fed if I recall by the feed from the pressure bypass valve on the front of the cases, so shouldn't be running dry and doesn't rely on the rocker feed for oil. The cam follower shafts are lubricated by the drain from the top end.
If blocking the return hole in the oil tank sends oil to the rockers then thats what I would expect, the main function of the oil is for lubricating the spindles.
Many prewar machines ran dry top ends and a rocker oil feed was only introduced for the late c11's.
For a rebuilt motor the top end should have been liberally primed with oil and once the engine is above idle the higher pressures should be sufficient.
The most common problem with top end oil lines is leakage.
Is an after market in line oil filter fitted on the return side?
If you loosen a rocker oil nut slightly does it weep? It should

Title: Re: 1952 A7 oil to rocker box
Post by: Greybeard on 29.01. 2017 09:04
Many prewar machines ran dry top ends...

Am I correct in thinking that the early A's had no rocker oil feed?
Title: Re: 1952 A7 oil to rocker box
Post by: bsa-bill on 29.01. 2017 10:11
Quote
Am I correct in thinking that the early A's had no rocker oil feed?

Yes GB I think most early bikes had no feed to the rockers and indeed no covers on them either, possibly they got a squirt from an oil can before a journey and maybe some sort of misting device (not sure about that one).
Other forms of lube could have been - reservoir and wick - grease pot with screw top (you know what I mean)
Covers may well have to keep the rider clean
Title: Re: 1952 A7 oil to rocker box
Post by: duTch on 29.01. 2017 11:15

 
Quote
Am I correct in thinking that the early A's had no rocker oil feed?

 I think the first 'A7 Vertical Twins', and some singles had feed to one rocker (ex?/In *????*), but not the other   
Title: Re: 1952 A7 oil to rocker box
Post by: Bsareg on 29.01. 2017 13:29
C11 handbook says "top end is lubricated by oil mist". Possibly  OK if used engine gets good and hot but doubtful when used for short journeys, maybe this is why they added an oil feed later. I fitted the mod to my  C11 in 1964 and could hear the difference a proper oil feed made
Title: Re: 1952 A7 oil to rocker box
Post by: chaterlea25 on 29.01. 2017 21:48
Hi All,
Going back to the original question..

Anjimehra
What size holes are in the banjo bolts ?
I know that there are quite a few different size drillings to suit various models ?
Next Question, does the early A7 have the same size drillings as the late A7/10 ??

John
Title: Re: 1952 A7 oil to rocker box
Post by: muskrat on 03.02. 2017 08:52
G'day All.
I just did a flow test on my 51. Opperating temp, fastISH idle, before banjo's. New 25/70 oil & KN153 filter in line before rockerbox junction, 2 beers after work!
2 minutes = 12ml. So not a loy.
Cheers
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 05.02. 2017 11:18
Hi Muskrat & Chaterlea25
Sorry for not responding earlier, but just got time to go back to the bike. Heres what I have checked:
1) Loosening the banjo nuts indicates oil reaching the end of the rocker spindles. Closing the return hole in tank increased pressure Inserted a a washer with a smaller dia ( 2mm ) hole in the return pipe to increase pressure to rockers. Ran the engine for 5 mins on fast idle. No oil present in the rocker box. Tappets etc bone dry
2) Dismantled the rocker box & checked spindles for blockage. All clear
Engine very noisy. Suspect no oil reaching camshaft & timing gears also. How do I check if the relief valve is operating w/o a pressure gauge? Will malfunction of relief valve cause excessive valve gear noise?
By the way, return oil is coming in bursts, as I think it should, considering return pump capacity = 2 x feed pump

HELP !!
Thanks
Anji
Title: Re: 1952 A7 oil to rocker box
Post by: bsa-bill on 05.02. 2017 11:43
Quote
Loosening the banjo nuts indicates oil reaching the end of the rocker spindles.

Do you have an old type oil can with thumb lever, if you do could you try squirting oil into the end of the rocker shafts, - a bit of a long shot but would eliminate the shafts - leaving the banjo bolts
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 06.02. 2017 17:09
Opened the prv & it was completely dry. Poked a wire as far as it would go in both the gallery from pump & one to the camshaft. Timing chest had oil in it when I took off the outer cover . Totally foxed !?
Anji
Title: Re: 1952 A7 oil to rocker box
Post by: chaterlea25 on 06.02. 2017 19:34
Hi Anji
I would remove the oil pump and see if oil is flowing through from the oil tank
Carefully strip the pump and check its condition, They can seize up when left idle and then shear the gears or drive when the engine is run  *sad2*
No oil at the PRV means no oil was going to the crank *sad2*

John
Title: Re: 1952 A7 oil to rocker box
Post by: muskrat on 07.02. 2017 18:25
G'day Anji.
I agree with John. When the oi; pump is off, use an oil can to pump oil in the feed hole and see if any gets to the prv. It might have spun bronze bush inside the steel case main bearing blocking the holes.
Cheers
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 16.02. 2017 07:56
Quote
Loosening the banjo nuts indicates oil reaching the end of the rocker spindles.

Do you have an old type oil can with thumb lever, if you do could you try squirting oil into the end of the rocker shafts, - a bit of a long shot but would eliminate the shafts - leaving the banjo bolts

Hi Bill
Thanks. Stripped the rocker box again & checked oil galleries. All clear, so problem elsewhere. will strip the pump & see.
Anji
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 16.02. 2017 08:03
Hi Anji
I would remove the oil pump and see if oil is flowing through from the oil tank
Carefully strip the pump and check its condition, They can seize up when left idle and then shear the gears or drive when the engine is run  *sad2*
No oil at the PRV means no oil was going to the crank *sad2*

John

Hi John
Will strip the oil pump today. However, if its a pump problem, how is the timing cover full of oil everytime I remove it , & oil is returning to the tank? I have also squeezed petrol into the horizontal gallery in the PRV housing & it comes out into the inner timing cover. oil pump nuts are tight.Anji
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 16.02. 2017 08:05
G'day Anji.
I agree with John. When the oi; pump is off, use an oil can to pump oil in the feed hole and see if any gets to the prv. It might have spun bronze bush inside the steel case main bearing blocking the holes.
Cheers
Hi Muskrat
Good point will check today. Thanks
Anji
Title: Re: 1952 A7 oil to rocker box
Post by: chaterlea25 on 16.02. 2017 20:51
Hi Anji,
Only a strip and examination of all the parts will reveal the problem *????* *????*

Quote
I have also squeezed petrol into the horizontal gallery in the PRV housing & it comes out into the inner timing cover. oil pump nuts are tight.Anji

That does not sound good ?????

While you are at it arrange something to rest a screw driver on and under the crank nut
Try and lever the crank upwards, if theres movement then the main bush is in trouble  *sad2*

John
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 03.03. 2017 06:51
Just clearing my own thinking on the general subject of lubrication. As far as I understand, oil from the pressure side of the pump travels via the PRV to the mains & big ends. From there it drips into the sump to be returned to the tank. When the oil pressure exceeds 50 psi the PRV lifts & allows oil to the cam shaft & timing chest. Sop, if the pRV is dry, presuure side of pump not delivering ?? Is this possible as the pump is working & oil returning to the tank, albeit in spurts & not a continuous flow.
Could someone please sort this out for me
Thanks
Anji
Title: Re: 1952 A7 oil to rocker box
Post by: muskrat on 03.03. 2017 10:15
G'day Anji.
The oil is fed to the bush, from there it's fed to the big ends. It also branches off to the oprv. If the pressure builds to 50 Lb excess is then diverted to the cam & timing gears.
From what I read the bush has spun depriving all but the sump, oil. What oil is getting to the sump is picked up by the scavenge side of the pump and returned to the tank.
I hope I'm wrong, but if anyone can come up with a better explanation, a total strip is in order.
Cheers
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 04.03. 2017 06:52
G'day Anji.
The oil is fed to the bush, from there it's fed to the big ends. It also branches off to the oprv. If the pressure builds to 50 Lb excess is then diverted to the cam & timing gears.
From what I read the bush has spun depriving all but the sump, oil. What oil is getting to the sump is picked up by the scavenge side of the pump and returned to the tank.
I hope I'm wrong, but if anyone can come up with a better explanation, a total strip is in order.
Cheers

Thanks Muskrat. Not looking forward to this.
Another thought. If oil branches off to the prv on the way to the mains, then why is the prv dry ? If the pump is delivering, then irrespective of whether the bush has rotated, oil should reach the prv. Have stripped the pump & all seems in order. As a precaution have lapped the pump end covers. Tried blowing compressed air from the prv housing end, but not exiting from the pump end port. Am sure all galleries were cleared before assembly.
Anji
Title: Re: 1952 A7 oil to rocker box
Post by: duTch on 04.03. 2017 09:34
 
Quote
... Tried blowing compressed air from the prv housing end, but not exiting from the pump end port...

 Isn't the anti syphon valve in there, which would stop the air?
 Maybe blow the other way?
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 04.03. 2017 12:12
Quote
... Tried blowing compressed air from the prv housing end, but not exiting from the pump end port...

 Isn't the anti siphon valve in there, which would stop the air?
 Maybe blow the other way?
Hi Dutch
Tried blowing from both ends ie. from the prv side as well as from the delivery port on the case.
Anji
Title: Re: 1952 A7 oil to rocker box
Post by: muskrat on 04.03. 2017 19:58
If the bronze bush inside the steel casing has spun the holes will not line up preventing oil to go anywhere but seep out the pump or around the outside of the bush. Solid bronze bush's are safer than the 2 piece variety.
Cheers
Title: Re: 1952 A7 oil to rocker box
Post by: trevinoz on 04.03. 2017 20:01
But oil will flow around the outside of the bush into the prv port.
Title: Re: 1952 A7 oil to rocker box
Post by: muskrat on 04.03. 2017 20:21
The plot thickens.
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 05.03. 2017 17:19
But oil will flow around the outside of the bush into the prv port.
So, no oil in the prv means what ?
Anji
Title: Re: 1952 A7 oil to rocker box
Post by: muskrat on 05.03. 2017 19:04
G'day Anji.
I still think it's a strip down, there's something amiss down there that would only end in tears if it's ridden.
Cheers
Title: Re: 1952 A7 oil to rocker box
Post by: trevinoz on 05.03. 2017 20:17
Anji, oil flows to the main bearing and prv via the check ball behind the pump. If the pump is working and actually pumping oil, the gallery behind the pump is either blocked or open to the sump.
Have you tried poking a wire into the delivery port to see if the ball and spring are there? With the ball depressed the gallery to the main bearing should be able to pass fluid.
If the ball, spring and plug are missing, fluid will flow straight to the sump.
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 08.03. 2017 06:53
Anji, oil flows to the main bearing and prv via the check ball behind the pump. If the pump is working and actually pumping oil, the gallery behind the pump is either blocked or open to the sump.
Have you tried poking a wire into the delivery port to see if the ball and spring are there? With the ball depressed the gallery to the main bearing should be able to pass fluid.
If the ball, spring and plug are missing, fluid will flow straight to the sump.

Hi Trivinoz
OK, as I understand, oil from the pump goes to the main shell circumferential oil groove  via the anti siphon valve, the to the PRV from where it travels at an angle up to the cam shaft well, lubricating the timing gears en route via a small pin hole.
So, if oil isn't reaching the prv, it could be
a) the a/s valve is not lifting to allow oil through, OR
b) there's a blockage in the line. The bush can't turn as it is one piece bronze
c) oil pump not working. It appears to be working as oil is returning to the tank
I have opened up the pump & lapped the 2 end covers. All else in the pump seems fine
Hoping I don't have to open the engine
Title: Re: 1952 A7 oil to rocker box
Post by: muskrat on 08.03. 2017 10:52
Hi Anji.
With the pump removed the top right hole in the casse is the supply to the main bush. poke something in there to feel if the ball is stuck. It should only take very light pressure to push it back. Now get an oil can and hold it firmly against the hoke and pump. Oil should come out the prv hole.
Cheers
Title: Re: 1952 A7 oil to rocker box
Post by: JulianS on 08.03. 2017 11:20
Check that the pump is sitting square on the crankcase and make sure the holes in the gasket between pump and crankcase are big enough and do not overlap and slightly mask the holes. Some gaskets offered have holes which are far too small.

If you are using an original oil pump they do distort over the years due to tightening the fixing nuts and the zinc alloy material. The oil chambers can squash a bit reducing pressure and making the pump stiff to turn over.
Title: Re: 1952 A7 oil to rocker box
Post by: trevinoz on 08.03. 2017 20:20
If oil is returning to the tank, it is obviously reaching the sump.
For oil to reach the sump it can be from the main bearing, the big-end bearings, the PRV via the cam trough and timing gears orifice. Also oil can escape from the pump shaft and when the level in the pump chamber is reached oil will flow into the sump through the crankcase wall.
Another route is through the check ball gallery if the ball, spring and plug are missing.
 Good luck, Anji.
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 10.03. 2017 07:50
If oil is returning to the tank, it is obviously reaching the sump.
For oil to reach the sump it can be from the main bearing, the big-end bearings, the PRV via the cam trough and timing gears orifice. Also oil can escape from the pump shaft and when the level in the pump chamber is reached oil will flow into the sump through the crankcase wall.
Another route is through the check ball gallery if the ball, spring and plug are missing.
 Good luck, Anji.

Thanks Trevinoz
Another question. I dismantled the pump, lapped the end covers, washed thoroughly & reassembled. Now the pump dose'nt turn by hand, & only does so if I slacken off the bolts a wee bit. Is it OK to assemble as such or will the will the crank worm wheel screw up the pump worm( or vice versa ).Thanks
Anji
Title: Re: 1952 A7 oil to rocker box
Post by: muskrat on 10.03. 2017 18:52
G'day Anji.
Re-built pumps will often do that especially if the gears haven't been put back in exactly the same way (tooth for tooth match). The screws must be tight. I find spinning the pump with your thumb whilst doing the screws up one by one a little at a time often works. It may take a few goes to get it right.
Cheers
Title: Re: 1952 A7 oil to rocker box
Post by: bsa-bill on 10.03. 2017 21:08
I should learn to leave well alone but both bikes have pumps I've checked??? and put together again, both were stiff to turn (for the reason Muskrat states) and both have oiled the engines successfully since
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 11.03. 2017 05:47
Thanks Muskrat &  Bill
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 13.04. 2017 17:11
Hi all
Finally got the time to strip the engine again & this is what I found
The the anti siphon ball valve had somehow jammed. I had to hammer it off the seating. Any ideas. The ball is the right dia I think & the spring is original. Feel some ham fisted previous owner has hammered the ball a bit too hard whilst reseating it.
As a consequence of Lub failure, the main shaft had turned, probably after seizing. Will now check the big ends. Dreading what I'll find. No metal bits in the sump.
Any suggestions on what I should do to the anti siphon set up
Thanks
Anji
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 13.04. 2017 18:07
Meant the main shaft bush. Sorry
Title: Re: 1952 A7 oil to rocker box
Post by: muskrat on 13.04. 2017 21:29
G'day Anji.
Bugga! You can buy new ball & spring. Re seat the ball (I get two balls ( *eek*) and use one to re seat (then throw away) and the other to use. You may need to run a drill down the hole to clean the seat just a tad, and then just a light tap on the disposable ball to seat it.
As usual a $2 part failure causes $1000 damage.
Cheers
Title: Re: 1952 A7 oil to rocker box
Post by: chaterlea25 on 13.04. 2017 22:30
Hi Anji,
I am a fan of converting to the A65 system where the ball sits against the back of the oilpump
Since the engine will be fully stripped down its an easy job, You need to take extra care with the pump gasket so it does not interfere with the ball seating on the pump face

John
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 14.04. 2017 05:41
G'day Anji.
Bugga! You can buy new ball & spring. Re seat the ball (I get two balls ( *eek*) and use one to re seat (then throw away) and the other to use. You may need to run a drill down the hole to clean the seat just a tad, and then just a light tap on the disposable ball to seat it.
As usual a $2 part failure causes $1000 damage.
Cheers
Hi Muskrat
Thanks for feedback. Not really looking forward to redo the whole fricking lot. Will take your advice on the seating. Camshaft was dry. Only ran the engine for maybe 4to 5 minutes. Still don't understand how oil was returning to the tank.
Thanks & cheers
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 14.04. 2017 06:24
Hi Anji,
I am a fan of converting to the A65 system where the ball sits against the back of the oilpump
Since the engine will be fully stripped down its an easy job, You need to take extra care with the pump gasket so it does not interfere with the ball seating on the pump face

John
Hi John
Thanks for feedback. Not quite sure what you mean having never been inside a A65, John.
Title: Re: 1952 A7 oil to rocker box
Post by: JulianS on 14.04. 2017 09:56
The A65 ball and spring fit from the oil pump side rather than from inside the crankcase making it easy to get at and easy to reseat the ball on the oil pump.

SRM end feed converted engines have the ball and valve fitted this way.

Photo from A65 workshop manual.
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 15.04. 2017 15:19
The A65 ball and spring fit from the oil pump side rather than from inside the crankcase making it easy to get at and easy to reseat the ball on the oil pump.

SRM end feed converted engines have the ball and valve fitted this way.

Photo from A65 workshop manual.

Thanks Julian.
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 17.04. 2017 09:41
The A65 ball and spring fit from the oil pump side rather than from inside the crankcase making it easy to get at and easy to reseat the ball on the oil pump.

SRM end feed converted engines have the ball and valve fitted this way.

Photo from A65 workshop manual.

Thanks Julian.
What is the dia of the ball . Iam doubting this as otherwise there is no reason for the ball to stick
Title: Re: 1952 A7 oil to rocker box
Post by: JulianS on 17.04. 2017 10:02
1/4 inch.
Title: Re: 1952 A7 oil to rocker box
Post by: anjimehra on 17.04. 2017 11:33
1/4 inch.

Thanks Julian