Author Topic: Sludge traps and pistons  (Read 1869 times)

Offline PDMiller

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Re: Sludge traps and pistons
« Reply #30 on: 23.10. 2018 20:14 »
Hi John
The crank is drilled from the threaded end, the drilling extends up into the gallery that contains the sludge trap and from there oil flows through the two holes in each big end journal. Not sure what the quill is that you mention but I'll check it out tomorrow. Does it supply oil to the timing side bearing? The bearing is exactly the same as the one in the diagram posted by Muskrat.

I checked the end float today and what a surprise it was .040". No doubt due to the complete absence of any shims. I got it down to .004" so that'll do. The bike was bought from a deceased's estate and I can't help but wonder if a spirit with a wicked sense of humour is having a good old giggle somewhere >:D
Thanks for your attention.
Pete
Late extra. I've been reading about these timing side bearing conversions and apparently that side now takes the axial thrust so no shimming required at the drive end. *conf* Not sure at all about the oil supply now. Will take photos tomorrow. *cry*

Online chaterlea25

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Re: Sludge traps and pistons
« Reply #31 on: 23.10. 2018 23:03 »
Hi Pete,
A steel tube is pressed into the drilled end of the crank, this is then machined to run true.
The oil feed is diverted either to a block "welded" into the outer timing cover fitted with an oil seal or to the jiggery jig
linked to on the Beeza Bill thread

There is no need for shims when the combined roller / ball bearing is fitted
I mentioned earlier that the outer ball bearing cone is held tight by a spacer placed outside it and clamped by the timing pinion and nut

Attached is a pic of a modified timing cover that I found on another thread
Also a borrowed A65 pic from SRM's website showing the diverted /added oil galleries

I feel that you need to do a lot of research and study the parts you have carefully in order to successfully complete this rebuild, as its non standard and there's no written manual for end fed setups

John


1961 Super Rocket
1963 RGS (ongoing)

Offline PDMiller

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Re: Sludge traps and pistons
« Reply #32 on: 24.10. 2018 08:07 »
Morning All.
Looks like I have half of an SRM conversion. *roll* The case has obviously been machined out to take the new bearing and the crankshaft has been drilled through to the oilway but no quill so there's no means of getting oil to the big ends. Idon't know what those 2 grub screws are for either side of that gallery.
My first inclination is to see if I can return everything to standard with an oversize bush and a plug in the end of the crankshaft.
All ideas and theories most welcome.
Thanks again to those who spotted this, not being familiar with these engines I might've just built it up. *doh*. (Mind you I'm getting more familiar by the day)

Offline Topdad

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Re: Sludge traps and pistons
« Reply #33 on: 24.10. 2018 10:26 »
Good morning Pete, I've had the timing side bearing and end feed conversion done by SRM quite a few yrs ago ,( thats on the bike by the way and not to me  *whistle*)  I'd suggest a call to them . When they do a job they keep records and I've always found them very helpful. Also they need the crank cases ,obviously the crank the pump and the inner and outer timing cases ,they mark there jobs similar to that on Johns t/case in the picture ,if you can find a number on anything that would be a real boon for you as they can trace the job ,also they may record the engine number . It'll only take a few minutes and could bring you an alternative way of completing this rebuild , even if they could refit a quill that would be a step forward, lets know how you progress, Bob.
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Offline Swarfcut

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Re: Sludge traps and pistons
« Reply #34 on: 24.10. 2018 10:36 »
  Hi Pete. Once more it is decision time. To state the obvious and for the benefit of those to whom it is a mystery, this is how the oil system is supposed to work. These engines have what is known as a "dry sump". The oil pump can be considered as two pumps, side by side. Any oil that collects in the crankcase is returned to the oil tank by the scavenge side of the oil pump, which has a larger pumping capacity than the feed side.

    Oil from the tank is drawn by gravity and suction into the feed side of the  pump, which then forces the oil  under pressure through a spring loaded non return ball valve, and then to the back of the timing bush. The bush sits tightly in a nice smooth housing machined in the crankcase, which in an ideal world is perfectly in line with the drive side bearing in its housing. The back of the bush has an annular oilway and oil holes to feed oil to the bush bearing surface and also by a miracle of hydraulic dynamics, feed oil into the crankshaft oilways and then to the big ends. The bush oilway connects via another drilling to the pressure relief valve. Depending on the model year, this surplus oil pressure vents to the oil pump cavity on early models, or as in your later version, passes to the camshaft trough via internal oilways in the timing side crankcase.

  Now we come to the tragic bit. If the non return valve leaks when the bike is parked up, oil will pass through the pump, through the oilways and timing bush and accumulate in the sump. This termed "wet sumping", and is dependent to a degree on the bearing clearance and the wear in the pump and bush, and the inability of the valve to seal against gravity flow. This is of no real consequence on a machine in regular daily use, but manifests itself frequently on bikes parked up for longer periods. Here a sump plate with a convenient drain plug is a good idea. There are various options to deal with this phenomenon.

  Now to consider your findings. In a conversion such as yours, you should find a non standard oilway somewhere that has  been machined or plumbed into the housing to connect to the relief valve. Without removing the bearing outer to check, there should be a free flowing connection between the hole with the valve in it, (Oil pump pressure output....  push a matchsick into the hole, you should feel a spring loaded ball) and the oilway at the back of the relief valve location. Even if this has been done you can still go back to standard. If it has not been done, then you have to decide whether to go down the conversion route completely, or stick to standard. No new oilway anywhere would indicate either a poor knowledge of the engineering considerations, or a failure to complete the conversion.

  Without this oilway, the oil has reached a dead end, and you have no way for oil to reach the relief valve or any subsequent arrangement to feed the crank oilways.  So this is the deal breaker.....oilway in place? Stick with the conversion..  No new oilway? The bearing will have to come out either to machine an oilway or go back to standard.

   Chaterlea John has given us some excellent views of what in involved. You need to find out how far the conversion has been completed, as you are already a good way there. The bearing design cannot hold oil pressure, meaning  the crank oilways must be fed in a different way, the most obvious is from the end, hence the various designs to achieve this.  The roller bearing may or may not have its own oil feed, but as oil will accumulate in the oil pump cavity, there is probably enough there to allow it to survive.

  If you stick to standard, remember over time the crankcase location for the bush may not be round, it may be also be gouged and abused. Any leakage between the housing and the outside of the bush  will result in loss of some oil pressure to the bearings. This location can be bored out if necessary, and an oversized O.D bush obtained.  Also, for the best result, after installation the bush should be line bored (in line with the drive side bearing location) to give the final running clearance.  If you are lucky and the case is OK, choose a one piece bronze bush of smaller size than your crank, to allow for final line boring to size. If the crank is worn or scored, just get it ground just enough to clean up the journal. Then choose your bush.  Remove material from a relatively cheap bush rather than a rare expensive crank.

   SRM are the experts here if you stick with the conversion and are a good starting point for more information. A fair amount has already been invested in this motor, and removing and reinstalling the roller bearing may not be easy, so think of your options and cost/benefit considerations. Done properly the conversion will give a long lived reliable engine. If SRM did the original conversion they should have a record.

  Hoping this helps, and will assist you in your next move.


   Swarfy.

Offline duTch

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Re: Sludge traps and pistons
« Reply #35 on: 24.10. 2018 11:29 »
 Having all that ^^ said, before doing anything it may be worth measuring the T/S journal and compare to standard to see if it's been machined to accommodate the conversion sleeve...and generally see where it's at  *dunno*
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Online chaterlea25

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Re: Sludge traps and pistons
« Reply #36 on: 24.10. 2018 12:15 »
Hi Pete and All,
As said the crank timing side journal is machined down to fit the bearing inner
The conversion does not look like an SRM
one , the tube fitted  in the photo looks threaded and a plug added at the outside
SRM fit a plain tube and weld over the outside,
It maybe a very early version though??
The conversion is almost complete it would make sense to complete it as what would have been the expensive part of the work is already done

John
1961 Super Rocket
1963 RGS (ongoing)

Online cyclobutch

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Re: Sludge traps and pistons
« Reply #37 on: 24.10. 2018 13:12 »
Roger at Cake Street was devising his own version of this some years back. Not sure if he ever put it into 'production'.
Various, including ...
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Online JulianS

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Re: Sludge traps and pistons
« Reply #38 on: 24.10. 2018 14:00 »
I dont think it an early SRM, mine was done by them back in 1984 when they were in Penarth.

The photos show that setup.

In the last photo you can just see the oilway going to the PRV.

No oil bleed to main bearing in the large needle roller outer.

Offline PDMiller

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Re: Sludge traps and pistons
« Reply #39 on: 24.10. 2018 18:08 »
Pressed the bearing out today and no machined groove linking the oil holes. The bearing outer case has an annular groove with a hole through to the inside but the groove doesn't line up with the holes in the casing. Also for some reason the inlet to the pressure relief  valve has been blanked off with a grub screw. The inner race just about fell off revealing a rough machining job below and I thought I read somewhere that the two flats inside the case that help locate the bush should be removed when boring the casing but strangely they have been left on.
I haven't got much confidence in the way this job has been done so I've just about decided to see if I can go back to standard . Going to see the local engine re conditioner on Friday to see if he can sleeve and regrind the shaft stub back to standard. Also as the casing has been bored out I'll need an oversize bush or a sleeve to adapt an original
No sign of the non return valve Swarfy but I've had reasonable success with the external ones on a couple of my other bikes so might use one of those.
Success today  *yeah*,managed to clean loads of bits and even fitted and reamed 2 new little ends  *lol* So I'm quitting while I'm ahead and settling down with a beer to contemplate the meaning of life Maybe try to work out why we continually put ourselves in stressful situations in the name of old motorbikes. *conf*.
Thanks again for all the input.

Offline Swarfcut

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Re: Sludge traps and pistons
« Reply #40 on: 24.10. 2018 19:18 »
 Pete, the ball valve should be  behind the small slotted plug on the inside of the crankcase, adjacent to the bearing location. With all the chaos you have found, this could have been removed or not re assembled. If the crank can be sleeved to run in a bush, you will have to re drill the sleeve to join the oilway to the big ends.  iI am thinking another crank may be your best option.

   Swarfy.

Offline PDMiller

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Re: Sludge traps and pistons
« Reply #41 on: 24.10. 2018 19:52 »
I'll check that tomorrow Swarfy  I noticed the plug today but didn't realise that's what it was. New crank would deffo be the best option but none available just now. One will probably turn up as soon as I get it finished. No doubt it'll be in bits again so it's something to look out for.
On the subject of taking things to pieces twice I'm wondering now if I should strip the other 7 bikes to check the sludge traps. *conf*
One of them is a Hinkley Bonneville so that doesn't count
Cheers
Pete.
Might nip out and check that NRV now. ;)

Online RichardL

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Re: Sludge traps and pistons
« Reply #42 on: 24.10. 2018 19:56 »
My videos, always good for a laugh at my expense. This one showing removal of the oil retaining ball.

https://www.youtube.com/watch?v=5IaZnt5WHeI&t=12s

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Online chaterlea25

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Re: Sludge traps and pistons
« Reply #43 on: 24.10. 2018 21:24 »
Hi Pete and All,
There is probably a simpler solution to the anti drain ball /spring
It may already have been converted to the A65 system,
It is very simple to incorporate this when rebuilding the engine,
All that has to be done is enlarge the oil passage from the rear of the oil pump to towards the grub screw
Again all this has been posted in previous topics
The oil pump gasket needs to be a good fit on the studs and may need modifying slightly around where the ball will seat against the rear of the pump
The great advantage of doing this mod is if a wet sumping problem occurs its a much smaller job to access the ball valve

Pete,
If I were you I would seek the advice of someone who is very experienced on BSA A10 engine repairs, not somebody who just talks about repairing them  *eek*

John
1961 Super Rocket
1963 RGS (ongoing)

Online Greybeard

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Re: Sludge traps and pistons
« Reply #44 on: 25.10. 2018 00:22 »
When I see this topic in the list I want to sing, 'Sludge Traps and Pistons and warm woolen mittens. These are a few of my favourite things'.