The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: lillygunny on 21.06. 2019 19:39
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I have a Rocket Gold Star with an oil filter installed by Frank Diehl. Frequently oil blows out the breather when the oil is cold evan if I drain the sump beforehand. I have pried out the rubber seal in the filter and though that helped it did not solve the problem. Is there a low back pressure bypass filter available or other solution to this problem? Once the engine is hot it works fine. I use Silkalene 20/50 oil.
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The problem is probably not caused by the filter.
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Then what is the cause? Thanks
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What type of filter have you got? I had a look on Frank Diehl’s website but there’s no mention of an oil filter?
I have a Champion COF 103101S screw on type mounted in the toolbox. Works fine.
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Hiflofiltro HF147 with rubber seal pried out.
Thanks
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You could try an equivalent from another manufacturer, see if that helps.
Seems though that the HF147 is a rather standard filter, comparable to the Champion, and I do not see how prising out the rubber seal may help get a better return. It would seem logic that the oil would leak out without the seal, so if it doesn’t that would mean there’s almost no return pressure.
Following that, I am leaning towards TT’s opinion that the filter may not be the culprit here but that there’s something wrong on the oil pump return side
When you have emptied the sump, does it take a while for the oil coming out of the breather pipe or is it coming out immediately?
I would start by disconnecting the filter feed line (engine return) and see if there’s a good return flow. Just don’t let the engine run to long in that condition because there won’t be any oil going to the rocker box. Or If it’s not possible to disconnect the feed line, at least check the return in the oil tank. There should be a decent amount of oil gushing out of the return pipe.
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Very good immediate oil return in the tank. Sorry, I should have mentioned that. It takes about 10 seconds before the oil shows up underneath and then slows dow, stops totally in a minute or two, Frank said it is cold thick oil causing a higher back pressure and a different filter might work, but he didn't have one to recommend. In a previous oil filter thread it was mentioned to pry out the rubber seal in the filter.I will just disconnect the filter and go back to nondetergent oil but I was hoping someone else on the forum had this problem and resolved it.
Thanks.
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What other work did Mr. Diehl do on your bike when he installed the oil filter?
Richard L.
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Richard, complete engine rebuild with roller bearing conversion. I had installed an SRM oil pump about 500 miles prior to the rebuild.
Thanks
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Yes, bypass the filter completely and see if that has an effect.
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liily- there may be some crucial information missing here....
ie; Have you used this motor before adding the filter..
What type of filter head you are using...and exactly which seal did yo remove *conf2* ?
Some pics may help to explain some things
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G'day lilly.
duTch asked my next question. If using one of the filter heads commonly found on fleabay (Notrun type) it should use an RF153/KN153. I have these on both mine and still using the 60 ya old pumps with no problems.
https://tinyurl.com/y3ryxvrw
Cheers
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musky I bought a champion cof103101s off ebay for the very slow going new build , does anybody use these or know if they are ok to use they are for citroen cars apparently
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According to the Champion website that filter cof103101s is for a BMW series 3 model, just checked on ebay and a dealer is selling on oil filter kit with that filter, type this no. into ebay 372685007930 you can just read the number although it is upside down.
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musky I bought a champion cof103101s off ebay for the very slow going new build , does anybody use these or know if they are ok to use they are for citroen cars apparently
I have one on the SA. Small enough to hide in the toolbox, easy to install.
No visual difference in oil tank return flow.
The only thing I do is fill the filter up with oil before screwing it on so the rocker box will get oil immediately on first start up
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And just having another thought. Does it have the sump plate kit with magnetic plug fitted?
As often discussed on this forum, if the magnetic plug is to close to the oil pickup it may hold the ball valve shut
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Hi All,
The first question to ask is
Are the pipes connected to the filter the right way round?
All these oil filters are designed to flow gallons of oil per minute *ex*
The low comparitive flow from the BSA pump should not pose any restriction to one
I have fitted filters to lots of different bikes without having problems
On my SR I fitted a thread adaptor so common 20mm filters fit I have been using small Peugeot/ Citroen filters as the filter head is fitted in the tool box
17 years on and lots of miles and no issues
I think the problem with lillygunny's bike will be the cork washer on the breather being too loose a fit
John
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Frank thinks it could be blow by from the rings not seating yet after the rebuild. So I will reconnect the return line to the tank, change to non detergent oil, put more miles on the engine, then try again.
On this forum I read that oil filters have a rubber flap to prevent oil draining backwards, but the flap also provides forward resistance and would raise back pressure. My filter is mounted vertically and will not empty when the engine is not running, so the rubber flap is not needed. Theoretically removing the flap should result in a low back pressure filter?? There are no oil leaks when the filter is bypassed so that is why this has been a mysterious problem.
Is changing the breather cork gasket a straight forward job? The oil lines are connected properly with excellent oil return in the tank.
Yes it does have an SRM sump plate with a magnetic plug, facing forward, and an SRM pressure release valve.
Thanks.
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Hi lillygunny,
You can check the rotary breather (cork washer) by removing the outer timing cover
The outer end of the breather top hat sleeve can be checked for end play by gripping the end of it with pliers
It should have zero end play
My method of setting how tight it should be is to see if I can rotate the sleeve by finger pressure (it is not a tight fit on the driving peg and will rotate a little ). If I can move it by finger pressure it is not tight enough, but it should rotate easily when gripped by pliers
The inner cover has to be removed to change the cork though
John
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musky I bought a champion cof103101s off ebay for the very slow going new build , does anybody use these or know if they are ok to use they are for citroen cars apparently
bergs, as far as I know they were a standard fitment for Noturn Commies, when I bought mine years ago....
lilli, a Hiflofiltro HF147 search shows that is replacement for various Yammies, so maybe a different head than current discussion...?
Musky- RF153/KN153 ? or HF ?
If you address Johns suggestion, and find you need thicker cork, and as around my woods no choice available, I cut gasket paper and packed behind the cork
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G'day duTch.
Yes HF153, dyslexic keyboard. Used on most Dupussies.
Cheers
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lillygunny, I thought this thread was familiar, and read through all your previous posts. This problem, or a variation of it first appeared way back in October/November 2018. This would really profanely upset me, as it looks to have already cost you a lot in time and cash. The problem looks to have never been resolved.
Is the oil definitely being pumped from the breather?
As you have a roller conversion, JulianS suggested a failure of the seal on the end feed to the crank, and this would be easy to check. But it has all the symptoms of wet sumping on start up, despite you draining the sump to start with. If the breather is not set up properly, then by my reckoning it will not improve by much as the motor warms up, so why the symptoms only when cold? If you can live with this inconvenience by all means put on a few careful miles, trust Frank. No improvement means back to basics.
So all in all a big puzzle, so do a few simple checks and start by bypassing the filter to eliminate that. There are lots of bikes running filters, you could just be unlucky that your set up has a fault, so take away that factor. Then a good check of the scavenge side... sump ball valve, a magnetic sump plug holding it shut? adequate lift available on the ball to allow good flow, pick up pipe integrity and oil tight connection on to the crankcase, pump gasket good, oil pipes clear with no kinks or restrictions.
The filter should be fitted between the crankcase and the rocker feed take off. Putting the filter last in line puts a restriction in the tank return, just enough to send more oil back to the rockers, and results in a build up of oil in the sump.
Worth also checking the PRV is working fine, ball and seat in good order, spring OK.
Swarfy.
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Swarfy, thanks a million for your analysis and suggestions. I will proceed and report the results, but it will take a bit of time!
Ron
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Just a further thought, if the motor was rebuilt by someone else. The breather passage crosses from one crankcase half to the other, and this junction must be oil and airtight, otherwise oil can enter the breather passage from the area of the camshaft trough. A post from way back had a similar problem and mentioned the retaining nut was found to not be tight and a 2 thou gap found between the halves. Any chance your build has been compromised in a similar way, and any gap closes as the cases warm up?
Swarfy.
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I use Citroen 2CV filters (ebay) on my toolbox mounted set up.
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Over a 5 month winter lay up, my bike wet sumps about a pint.
The funny thing is with the drain plug out i only get a couple of ounces. To get the rest i have to kick the bike over.
It acts like there is a vacuum inside the motor.
If yours wet sumps, try that next time. Maybe there is more oil in the bottom than you know and its escaping at start up through the breather?
Lee
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I am pretty sure I mentioned this LOTS more oil after kicking it bit some time ago, mine did the same as in threw extra out of the cases when I kicked it over , this was just out of the drain plug not with the sump plate off, bit of a vacuum me thinks, nothing to worry about--- not now anyway, it doesn't wet sump.
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Coater87 talks of vacuum. I think the problem is too fine a gauze in the sump, causing a vacuum effect.
Some time ago my GF was pouring oil out of the breather after start up. I had already drained the sump, so wondered what on earth was wrong. So I checked the sump again. Only a few drips, but a gusher when I kicked it over. So when I drained it originally, I had assumed that after the trickle died to a few drops that it was empty. It was not. What I’d drained was the oil below the gauze. It needed a little pressure to get the oil in the crankcase above the gauze to pass through the mesh.
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It acts like there is a vacuum inside the motor.
Maybe cracking a valve cover (exhaust be easiest) would let some air in but be a pain to do each time, so maybe a screw vent in the cover might work *dunno*
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It does wet sump evan with an SRM oil pump, about 8 ounces a week. I did run the bike for about 50 miles after the rebuild without the oil filter hooked up per Frank's advice and it never had any leaks. I started to worry about using 20/50 detergent oil so I hooked up the filter and the problem began, but only with a cold engine. Frank said it needed more miles because of ring blow by so I will bypass the filter and toss the oil every 50 miles. From my own research I realized that Frank put the SRM sump plate on backwards-drain to the front-so I will reverse it Friday and hope part of the problem was that the magnet was holding down the ball, causing the sump to fill up with oil. Will report outcome. Thanks for all the help and I will go through all the recommendations if it still does it without the filter in line.
Thanks,
Ron
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dutch that's a lot of messing about making a vent when all you have to do is move the crank a tiny bit with resting a leg on the kickstart, and the rest of the oil drains out, I think it gets vacuumed because my old sump plate had BIG holes muchos damage in it and in the days of it being stood a few weeks and wet sumping if I thought there was more in there I just prodded the kicker a bit and it all came out
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G'day fellas.
Both mine drain freely. The cafe is Bunn breather equipped and the A7 is std. The only vacuum is between my ears!
Both have sumps with the drain plug forward, again no problems. *dunno*
Cheers
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The only vacuum is between my ears!
Both have sumps with the drain plug forward, again no problems. *dunno*
*eek*
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Fool that I am, I supposed the sump plate was being removed to drain the oil, so RD's comment that the gauze will hold the oil by partial vacuum and surface tension will hold true. Looks like drain plug out and a few kicks should effectively achieve a drier sump for a proper start up.
Swarfy.
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bergs- that's a fair call, but in my defense *beer**fight* *beer* *fight*....
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Still doing it after filter bypass. Frank thinks it is a breather issue. Will check that out next week.