The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: anjimehra on 09.06. 2018 06:12
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Hi guys
Back to bother you again.
Valve gear on Both my A10 & A7 plunger is noisy. New valves, guides, seats. Tappets at .010 . Old pump. Noise persists even if I block the return pipe hole in oil tank Any suggestions. Otherwise running fine. Taken the A10 on a 1500 km ride to Goa recently
Ride safe
Anji(https://www.a7a10.net/forum/proxy.php?request=http%3A%2F%2F%5B%2F%5Bimg%5Dimg%5D&hash=60908bfc91c1ad9f6083dfe1522669515d4dbdae)
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Hi guys
Back to bother you again.
Valve gear on Both my A10 & A7 plunger is noisy. New valves, guides, seats. Tappets at .010 . Old pump. Noise persists even if I block the return pipe hole in oil tank Any suggestions. Otherwise running fine. Taken the A10 on a 1500 km ride to Goa recently
Ride safe
Anji(https://www.a7a10.net/forum/proxy.php?request=http%3A%2F%2F%5B%2F%5Bimg%5Dimg%5D&hash=60908bfc91c1ad9f6083dfe1522669515d4dbdae)
Just opened the rocker covers to find rocker box dry. oil coming up to the rocker feeds from return pipe . Have also cleared oil galleries in rocker shafts. Could it be an oil pump issue.
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G'day Anji.
Have you checked the banjo bolts are clear?
Do you have a solid feed pipe from the return to tank junction all the way to the banjos? I have a rubber hose section in mine so I can disconnect it (block off the tank side) and use an oil can to squirt oil up there. If you could do this to make sure there's no blockage. The banjos only have a small hole and there's not much pressure coming up to them so the rockerbox isn't flooded in oil, just enough to keep things wet.
I remember a while back you were having concerns with the pump. Did you do anything with that?
Cheers
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There are two kind of banjoblots with small hole and big hole. Check if the holes are blocked.
A good oilflow had to be with bolts loose.
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Both the banjos have 3/64" holes.
Cheers
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hi musky I think he means rocker box oil bolts which I have seen two different sized holes in some ive got knocking around somewhere
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Which are called banjo bolts https://tinyurl.com/y7brkqwo
Cheers
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G'day Anji.
Have you checked the banjo bolts are clear?
Do you have a solid feed pipe from the return to tank junction all the way to the banjos? I have a rubber hose section in mine so I can disconnect it (block off the tank side) and use an oil can to squirt oil up there. If you could do this to make sure there's no blockage. The banjos only have a small hole and there's not much pressure coming up to them so the rockerbox isn't flooded in oil, just enough to keep things wet.
I remember a while back you were having concerns with the pump. Did you do anything with that?
Cheers
Hi Muskie
I have removed the cu rocker feed pipe & blown it clear.Have also slightly enlarged the oil holes in the banjo bolts. Can only think of 2 other reasons 1) rockers are worn & or b) gears on the return side of pump worn out. I did solve the delivery pressure problem by finding & fitting new gears on the feed side. Fast idle pressure went up to 45 psi from 0 initially. Couldn't find the return side gears though. Still looking
Did you sort out your pressure problem Muskie
Thanks & cheers
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There are two kind of banjoblots with small hole and big hole. Check if the holes are blocked.
A good oilflow had to be with bolts loose.
Hi Klaus
See my reply to Muskie. I have enlarged the bolt holes slightly but no luck
Thanks
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o yes cheers musky I often wondered why the small holes were slightly different, different part numbers, another confused. com sorted cheers
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Anji, not a good idea to enlarge those holes. Their part of a metering system. If too big more oil will go up there instead of the oil tank and could overwhelm the scavenge side of the pump.
These are not actual figures but just an example. Imagine there's 100 ml/minute of oil going in the feed side and the scavenge side can pump 120ml/minute at the same revs (that's why there's bubbles in the return to tank oil). Now say the scavenge pumps 90 to the tank and 10 to the rockers so in reality there's 110ml going in but that's OK as the scavenge can do 120ml. With larger holes say 70 to the tank and 30 to the rockers means there's 130 going in which is 10 more than the pump can handle. In theory the sump will slowly fill and the tank empty. As I said this is just theory but could happen. By increasing the hole from 3/64 to 1/16 will increase the area of the hole by 77% which is a sh!t load.
If the oil line is clear the banjos are clear and the shafts are clear there will be oil up there. With the motor running loosen one of the banjo bolts, oil should emerge. Tighten that one and loosen the other, more oil emerges. Tighten both. Remove tappet covers, start motor, finger over return pipe in tank, should be able to see oil dribbling out the rockers. If not the pump can't give enough pressure to get through the bolt holes. Time to look at the pump. Lap the end plate on a piece of glass with wet & dry (400 grit) till the gear wear marks are gone.
Well that just about wore the print off my one typing finger!
Cheers
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If oil is going up the pipe check that washers are not covering and blocking the holes.
(edit) Added a picture to make it clear.
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Anji, not a good idea to enlarge those holes. Their part of a metering system. If too big more oil will go up there instead of the oil tank and could overwhelm the scavenge side of the pump.
These are not actual figures but just an example. Imagine there's 100 ml/minute of oil going in the feed side and the scavenge side can pump 120ml/minute at the same revs (that's why there's bubbles in the return to tank oil). Now say the scavenge pumps 90 to the tank and 10 to the rockers so in reality there's 110ml going in but that's OK as the scavenge can do 120ml. With larger holes say 70 to the tank and 30 to the rockers means there's 130 going in which is 10 more than the pump can handle. In theory the sump will slowly fill and the tank empty. As I said this is just theory but could happen. By increasing the hole from 3/64 to 1/16 will increase the area of the hole by 77% which is a sh!t load.
If the oil line is clear the banjos are clear and the shafts are clear there will be oil up there. With the motor running loosen one of the banjo bolts, oil should emerge. Tighten that one and loosen the other, more oil emerges. Tighten both. Remove tappet covers, start motor, finger over return pipe in tank, should be able to see oil dribbling out the rockers. If not the pump can't give enough pressure to get through the bolt holes. Time to look at the pump. Lap the end plate on a piece of glass with wet & dry (400 grit) till the gear wear marks are gone.
Well that just about wore the print off my one typing finger!
Cheers
Thanks Muskie. Agree with your logic. Beginning to think that it's the scavenge gears in the pump. Found some on eBay but part nos don't match my catalogue numbers. Need your advice on whether the one on eBay will do
Catalogue numbers scavenge 67-1386, 67-1385
eBay nos 67-1405, 67-1406, 67-1403, 67-1404
Thanks & cheers
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G'day Anji.
'47-'55 Scavenge gears 67-1385 & 67-1386, Feed gears 67-1383 & 67-1384 are correct for your pump. In '55 these were superseded with Scavenge gears 67-1405 & 67-1406, Feed gears 67-1403 & 67-1404. So yes the 1405 & 1406 will fit but MUST be a pair (not one early & one late). These gears went right through into the A50 & A65 models. Back in the day BSA would only supply the gears in a set of 4, scavenge and feed.
Cheers
PS: re your ? about my oil pressure problem. No, she's still going, no horrible noises. In fact the whole motor is quiet with 40/70 oil in there *sick*
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If oil is going up the pipe check that washers are not covering and blocking the holes.
(edit) Added a picture to make it clear.
Not covering the holes Roger. Thanks
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Quote from: RogerSB on June 10, 2018, 02:18:20
If oil is going up the pipe check that washers are not covering and blocking the holes.
(edit) Added a picture to make it clear.
Not covering the holes Roger. Thanks
Although anji's, if you've drilled the holes out, it may be advantageous.... *dunno*
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Anji, not a good idea to enlarge those holes. Their part of a metering system. If too big more oil will go up there instead of the oil tank and could overwhelm the scavenge side of the pump.
These are not actual figures but just an example. Imagine there's 100 ml/minute of oil going in the feed side and the scavenge side can pump 120ml/minute at the same revs (that's why there's bubbles in the return to tank oil). Now say the scavenge pumps 90 to the tank and 10 to the rockers so in reality there's 110ml going in but that's OK as the scavenge can do 120ml. With larger holes say 70 to the tank and 30 to the rockers means there's 130 going in which is 10 more than the pump can handle. In theory the sump will slowly fill and the tank empty. As I said this is just theory but could happen. By increasing the hole from 3/64 to 1/16 will increase the area of the hole by 77% which is a sh!t load.
If the oil line is clear the banjos are clear and the shafts are clear there will be oil up there. With the motor running loosen one of the banjo bolts, oil should emerge. Tighten that one and loosen the other, more oil emerges. Tighten both. Remove tappet covers, start motor, finger over return pipe in tank, should be able to see oil dribbling out the rockers. If not the pump can't give enough pressure to get through the bolt holes. Time to look at the pump. Lap the end plate on a piece of glass with wet & dry (400 grit) till the gear wear marks are gone.
Well that just about wore the print off my one typing finger!
Cheers
Hi Muskie
Have taken a video clip of the sound but the forum is not accepting it I think because of its format. Can I mail or whatsap it to you
Cheers
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Have taken a video clip of the sound but the forum is not accepting it I think because of its format. Can I mail or whatsap it to you
If I want the forum to see a video I upload it to YouTube and post a link to it here.
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If I want the forum to see a video I upload it to YouTube and post a link to it here.
That's what I do.
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G'day Anji.
Yes please mate. I'll then put it on youtube and post the link.
Cheers
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G'day Anji.
Yes please mate. I'll then put it on youtube and post the link.
Cheers
[/quote
Need your whatsapp number Mine is +919975292020
Cheers
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I often wondered why the small holes were slightly different, different part numbers, another confused. com sorted cheers
Rocker feed banjo bolts: As far as I know: small for inlet, large for exhaust - but for later Gold Stars only.
I believe there is also a similar bolt with a bigger hole used as a rocker drain bolt on the B series.
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G'day Fellas.
Uploaded a video from Anji. https://youtu.be/7xFTj58ghF8
Anji, can you use a stethoscope to pin point the rattle? Most likely in the valve train but is it front or back of the rockerbox, or lower down at the lifters?
Cheers
PS: 1st time I've put up on youtube! Easier than I thought. Now I'm off twerk.
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Hi All,
It sounds to me like the "tack, tack, tack" is at engine speed *ex*
Pistons touching head gasket ??? (has happened *ex*)
John
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G'day John.
You may be right. I was in a rush this morning and only listened to it once.
Anji, what comp pistons and have the barrels been decked (lowers the gasket in relation to the pistons)?
All the gasket kits I've seen down here have head gaskets for the A10 not A7 so it's larger than the A7 bore. *dunno*
The other problem of the return oil flow being continuous could be due to the banjo bolt holes being opened up in order to quieten the "tappet rattle".
Cheers
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Hi All,
It sounds to me like the "tack, tack, tack" is at engine speed *ex*
Pistons touching head gasket ??? (has happened *ex*)
John
Hi John
The gasket is the right size & pistons low compression with flat top ( not domed ).
Thanks, Anji
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G'day Anji.
Have you been able to narrow down where the noise is coming from, top or bottom, drive or timing side? If you slowed the idle down it would be easier to tell if its full or half engine speed.
I notice there's no dynamo. With no dynamo drive sprocket there would be excessive end float of the idler pinion.
Cheers
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If you had the primary cover off, make sure one of the 3 forward most larger screws is not touching the crank and making that rattle.
I would just back them out a ways and see if anything changes.
Lee
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G'day Anji.
Have you been able to narrow down where the noise is coming from, top or bottom, drive or timing side? If you slowed the idle down it would be easier to tell if its full or half engine speed.
I notice there's no dynamo. With no dynamo drive sprocket there would be excessive end float of the idler pinion.
Cheers
Hi Muskie
Thanks for posting & feedback. Sorry for delay in replying as I was out of station. The noise appears to be from the timing side . Have put the dynamo drive sprocket back on but noise persists. There is a little play in the breather hole that fits on the cam gear wheel pin. Could the sound be because of the advance retard springs having lost their tension??
Cheers
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Timing side noises may be from wear in idler pinion or idler pinion bushes. Also possible that the crankshaft pinion may not be a tight fit on the shaft and is rocking on the woodruff key.
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.......There is a little play in the breather hole that fits on the cam gear wheel pin.......
Please explain further.. *conf*
........Could the sound be because of the advance retard springs having lost their tension??..
aaah... *conf2*...how do you figure that ???
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Timing side noises may be from wear in idler pinion or idler pinion bushes. Also possible that the crankshaft pinion may not be a tight fit on the shaft and is rocking on the woodruff key.
Hi Julian
Thanks., but the bushings have all been changed, & theres no excessive backlash in the gears.
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G'day Anji.
Clutching at straws now! I've listened to the video quite a few times now.
With the motor running pull the right hand spark plug cap off, keep it running on the left. Does the noise diminish? Then do the same the other side. This is the standard big end knock test.
Feel free to take more videos with varying revs and the above test and email it to me.
Cheers
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I have to say, when I recently managed to get a pushrod on the edge of the follower during tappet adjustment, that then dislodged, causing huge tappet clearance, the engine sounded rather like that: https://youtu.be/9AdUATO7uRI