Author Topic: Sludge traps and pistons  (Read 1906 times)

Offline PDMiller

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Sludge traps and pistons
« on: 19.10. 2018 10:37 »
After reading about sludge traps on his forum I decided that it would be a good idea to check mine on the new project. Following Swarfy's excellent instructions I got the plugs out. One was straight forward but the other one was a bit of a battle. The whole oilway inside was completely choked . luckily the engine has never run since being built up many years ago, if it had I think it would've been toast. *eek*. The other thing I noticed was that the bores are +.060 and the pistons are +.040. Luckily the bores are in good nick so new pistons are on order.
Oh well, my quick tidy up has turned into a Winter re-build.

Online Greybeard

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Re: Sludge traps and pistons
« Reply #1 on: 19.10. 2018 11:02 »
I am so glad you checked for sludge!
When I started restoring my machine I was not aware of sludge traps. I wasn't on this forum then, (I know!). Luckily I read someone's online account of keeping their A10 on the road for many years. They emphasised how important it was to clean out the crankshaft oilways periodically. When I opened mine up it was also very full.

Offline RichardL

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Re: Sludge traps and pistons
« Reply #2 on: 19.10. 2018 13:21 »
My story's kind'a like GB's, but ended up spinning a rod bearing. I think I am blaming   the Hayne's manual for not addressing the sludge trap in a meaningful way.

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Online Swarfcut

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Re: Sludge traps and pistons
« Reply #3 on: 19.10. 2018 14:36 »
 P D.....Thanks for that accolade. Nice to know it did some good.   Picture looks like a later "Big Journal" Crank    But you cannot relax. The next trial is to come.   What you think is a choked oilway is in fact a removable tube. Removable?  Well in a manner of speaking. One sludge trap plug has a small central pip to seal the end of the tube. The tube bells out at the other end, where the oil goes in. The tube is located by the radial flywheel securing bolt.  Once this is removed, the tube will come out, revealing even more sludge.  Like the plugs, some are easy, some have to be carefully drifted out,  or cut down the middle with a small hacksaw blade and collapsed inwards.

   Many folks have neglected to remove the tube for cleaning, leaving that sludge there to do its worst.  Take your time and do it properly.  Lots of information about re assembly on this forum. Some people change the flywheel bolts as here failure can also make it go bang.

    The earlier small journal crank is much simpler, just remove the plugs and clean everything.

    Note which way the Conrods are fitted.   Cap and rod numbers should match on each rod.  Matched rods are usually from the same batch, so the numbers stamped on them will be in the same style and close, rarely consecutive. Forging numbers also will be in the same font if they are matched original rods. For a big journal rod, the forging number is 67-1160.

  Opinion is that the rods are fitted with the numbers to the gearbox side, shell bearing locating tabs to the front of the engine.

 The left hand, drive side rod has a small hole from the bearing location to the bottom of the side of the rod. This should point towards the flywheel.

  See postings headed "Conrod Oil hole" for a bit more about this true purpose of this hole.

  Apologies if you know all of this this already, but if the previous owner couldn't match bores to pistons, even the basic assembly may be incorrect.
 
 Good to know you have made a start.

  Keep Spannering

  Swarfy.

   

Offline muskrat

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Re: Sludge traps and pistons
« Reply #4 on: 20.10. 2018 06:35 »
G'day Swarfy.
For that excellent tutorial I give you a Karma point.
Thanks for sharing your knowledge.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline PDMiller

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Re: Sludge traps and pistons
« Reply #5 on: 20.10. 2018 08:37 »
Thanks for that Swarfy.
The tube you mention was indeed caked solid with sludge.  All clean now and waiting for bits to arrive.
The engine numbers start with GA10R so I think that indicates that it's from a Road Rocket? Not sure what the differences are. This bike is a real bitsa so I'm looking forward to many cold and oily hours in the man cave. ;)

Online Swarfcut

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Re: Sludge traps and pistons
« Reply #6 on: 20.10. 2018 09:29 »
G'Day Musky. Thanks for your endorsement. Always difficult to know how much folks know about these motors. I am happy to pass on my experience.

 Hi Pete... Worth you following a current thread about main bearing set up. Your engine should have a 356 cam, Big Valve Alloy Head, High compression pistons. More vibration, and envy from lesser mortals comes as standard.   Together with a nagging worry when you leave it unattended.

  Spanner On

   Swarfy

Offline chaterlea25

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Re: Sludge traps and pistons
« Reply #7 on: 20.10. 2018 18:46 »
Hi All,
PD,
Could you check the engine number again?
C A 10 changed to D A 10 for 1960
"G" was not used by BSA on the A 10 engines

John
1961 Super Rocket
1963 RGS (ongoing)

Offline PDMiller

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Re: Sludge traps and pistons
« Reply #8 on: 21.10. 2018 15:39 »
Yes you're right John it's a C not a G. I wouldn't have been surprised if it had been an obscure number as nothing about this engine would shock me now.

After much internal debate and soul searching I convinced myself that I had probably put the sludge trap tube in the wrong way round and possibly screwed the plugs in too far. The crankshaft is still on the bench so the plugs had to come out again so that I could sleep at night. The plugs were just as stubborn second time round, probably due to loctite and centre punch dabs. I made up the little screwdriver tool in the picture and with a big G clamp to keep the pressure on they gave up without too much of a fight.
I made the tool out of a piece of allen key but a bolt head would probably do just as well and be much easier to cut with a hacksaw. Now to find a home for it where I can find it in 50 years or so when it needs doing again. *conf*
Cheers
Pete

Online berger

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Re: Sludge traps and pistons
« Reply #9 on: 21.10. 2018 16:42 »
I have not been to the pub, blinking ek how many hack saw blades did you get through *work*

Offline PDMiller

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Re: Sludge traps and pistons
« Reply #10 on: 21.10. 2018 17:02 »
it was already the right length  for a previous job can't remember what it was,( maybe an awkward diff plug) so i just had to cut the sides off to form the blade. Not too bad with a decent hacksaw blade. Couldn't be bothered to get the grinder out and gloves and find some goggles etc . I'm all for an easy life.  *smile*. Mind you it would've been quicker with the grinder.

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Re: Sludge traps and pistons
« Reply #11 on: 21.10. 2018 17:50 »
You do know you can buy hex socket plugs for our cranks now, don't you.

Offline PDMiller

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Re: Sludge traps and pistons
« Reply #12 on: 21.10. 2018 20:09 »
 Yes thanks I did see them after I had re-fitted mine. Just thought the allen key screwdriver might be handy for someone trying to remove an original one.
The latest little surprise was to find new big end shells fitted to a conrod which has obviously had a bearing spinning in it at some point. Suspect this all goes back to the sludge issue, the crank has obviously been reground and new bearings fitted but with the oilways completely blocked thankfully it has never been run since this work was done.
Oh well let's see if there are any conrods on Ebay  *conf*. This bike is full of little surprises.

Online Swarfcut

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Re: Sludge traps and pistons
« Reply #13 on: 21.10. 2018 22:45 »
 PD.  Before you condemn the rod, your local engine reconditioner should be able to reclaim the big end eye. This is a fairly common engineering procedure. If you are looking on eBay, remember there is  the one rod with the hole and the one without.  Also worth getting the journals checked to make sure the shells are the right size for the crank. New shells on a well worn crank journal are a waste of time and money.  Rod should be marked 67 1160 for a big journal crank.  Rods are identical apart from the drilled hole in the web of the drive side rod.   The timing side bush and its oil supply function are critical, plenty to read elsewhere on this forum.

   Loctite is easily softened by heat. Even a cheap hot air gun makes life easier fitting piston pins, bearings etc and freeing off those old rusty useful bits you pick up from time to time.

  Swarfy

Online Swarfcut

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Re: Sludge traps and pistons
« Reply #14 on: 21.10. 2018 23:02 »
 
 Pete, Just looked at your magnificent sludge trap device on the crank.. The crank looks a little different from normal.  Is that a protective sleeve over the timing side main bearing journal? All cranks I have seen have an annular oilway in that journal, and the journal is the same diameter from the crank cheek to the start of the timing pinion location. The drive side splines also look to have wear. They should be the same width  along the shaft. From the picture it looks as if they have a wear step.  If you do a search for BSA A10 Crankshaft Images you will see the difference.

 Swarfy.