Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board Where does sludge in the sludge trap come from?om

Started to "try" to remove the sludge trap on a basket A-65 a few weeks back. Realized its a little beast and scratched around for my drag link socket. Once found, the drag link socket was a little too big, but nothing a carbide cutter could not correct. Now find the little carbide cutter!!!

Got side tracked by the cold weather, chopping wood, grandson's car problems, daughter's car problems, my truck problems, caught covid and quarantined. More my truck problems.

Now all caught up mostly and thought about that little beast still stuck in my A-65 crank. Why is that sludge trap even there? One answer might be that modern oil filtering techniques had not yet been adopted. Which got me wondering where the sludge in the trap is coming from? Oh, its scavenged from the bottom of the crankcase by the oil pump back to the oil tank where it passes right through the oil screen at the bottom of the OIF and sucked back around by the oil pump to the crank and gets caught eventually by centrifugal filtering at the sludge trap. Oh!

So, if there was a proper oil filtration process, the sludge trap would be unnecessary. The sludge in the crank passage would exist elsewhere not at the most inviolate spot.

I need a proper oil filtration process. So far I have searched BritBike and found the words "Charlie type oil filter", "Motao filter". Just got to get it together.

The "sludge trap" is a short name for a full flow centrifugal oil filter.
It take out every particale of debris in the oil that is heavier than the oil regardless of its size .
They are very good & very efficient , till they get fully pluged up.
And the sludge is timy wear particles and carbon from combustion.

Quite correct. Modern engines with good filtration don't have or need sludge traps.

And stray bits of gasket sealer, rag lint, debris from the last time it was opened up and back in the old days.... tetraethyl lead .

The debris is a mix of worn engine parts which mainly includes very fine particles from the piston and barrel and parts that wear at a slower rate like cams.

As already mentioned, carbon from combustion is included and any other parts floating around like bits of the gasket.

The centrifugal trap works really well but can fill up rapidly if the engine oil isn't frequently changed.

I've got a Norton type filter on my A65, it was tricky to fit given its size, you can get smaller ones that fit behind a frame tube and accept Trident/Rocket 3 filters.

Also worth fitting a magnetic sump drain plate, the magnet on the end of the drain screw always has a covering of grey sludge when I undo it. I assume this is from the rings and barrel and would have ended up in the centrifugal trap.

Even with a good oil filter you will still get a soft sludge form in the sludge trap with mineral oils, probably not as much if you stick with the original service schedules. Keeping it is a good thing for a road going motor.

Have you managed to remove the trap now? Many people forget or don't realise that the flywheel bolt that mounts above it has a longer teet just for securing that sludge trap. If you haven't done already, you'll need to remove it.

Carbon black is denser than oil and finer than the pores in a full flow paper filter.

Simple as that.

Cleaned up my garage today. Tools and debris were all over the place from 3 automotive jobs and one more to be completed. So, sludge trap not pulled yet. Will post a photo once out. The trap cap is driven a few threads deep and it was good to have read the post by Morgan A.K.A. about removing a Triumph sludge trap with the flywheel bolt removal requirement. Guessed it would be the same. That soft sludge build up that Alan G. pointed out in the trap even with a supply filter installed and regular maintenance seems like a distinct possibility since the trap is a low velocity section of the oil supply relative to other lines and the centrifugal filtering effect .I would like to think this could be overcome by modern oil engineering which provides for the possibility of an almost spotless engine if not spotless as far as sludge with proper filtration assumed. An appropriate amount of diesel added at warm idle for 10 minutes and immediately followed with a fresh oil and filter change will help eliminate sludge due to diesels detergent qualities.

I'm not expert but carbon in the oil is normally the least thing to worry about. I believe it is collodial and unfilterable. If it was very detrimental then wouldn't the diesels all be blowing up? Granted diesel oil is engineered to allow for much more carbon in the oil then a gas engine, and of course some oils can be run in both.

Again, I'm not expert but the snot ball of sludge exactly in the supply to the rods and drive side bearing is an obvious concern.

I was at some point in the past familiar with marine steam turbine bearing oil centrifugal cleaners. Guess what? These had continuous cleaning maintenance as they were in operation. A skimmer band sluffed off the layer of undesirables as the machine operated. Unlike the BSA sludge trap which is only cleaned at engine useful end of life or there abouts.

Its pretty clear where the sludge in that A-65 crank sludge trap comes from: supplied from the unfiltered oil tank.

Found:
1) "Charlie's filter" 19-4589, 99-1179 Oil filter element, BSA unit singles & T140 at Mike Boulton Motorcycles in UK.
2) BSA Triumph Oil In Frame Singles Oil Filter PN# 99-1179 19-4589 FB994/1 at The Bonneville Shop

So, I'm guessing the OIF singles have no crank sludge trap?! Also, T140 no crank sludge trap?! Are the filters for these bikes in the oil supply line to the oil pump?

Not found yet: Motao filter

Hey, just not about to build any engine without proper oil filtration. Hey, Fram is ok by me. No filter: NOT OK!

I use a TriCor filter on my B44. It’s a Triumph T150 Triple oil filter. Easy to fit.

"Again, I'm not expert but the snot ball of sludge exactly in the supply to the rods and drive side bearing is an obvious concern."

You got it. Well, the rods anyway, particularly the left one. The DS bearing is not fed through the crank.

Stop making these guesses.

I know of A65's that run with the T140 style filter in the down tube, they run just fine. It works because you have about 2 litres (or about 1.6kg) of oil sat directly above the filter. It wouldn't work the same if you put a external filter in the feed line without either having that weight or pump pressure behind it. Thats why most oil filters fitted to pre OIF twins (and the likes of the WDB40) are mounted in the return line. nothing to do with the sludge trap.

If you look at a sludge trap you will see that the oil feed from the trap to the main gallary is in the inner side (facing the centre of the crank), so when sludge accumulates on the outer most point it will still get oil to the big ends. If that trap wasnt there then the left side rod would block much more quickly.

You must not have done much of a search on oil filters -
https://www.britbike.com/forums/ubb...for-internal-cartridge-filter#Post865983
A centrifugal filter is very effective. By the time the trap in the crank filled to where it would block the oil path the engine would have to be rebuilt for other reasons.Some people, like Pat Owens, Triumph service manager and Romero's mechanic, have run a T120RT 400,000 miles with the original head, valve seats, cylinder, crank and engine cases ("Triumph in America", pg 93).
If the trap were not in the crank, the hole through the centre would be only the diameter of the oil passage. Otherwise sludge would accumulate and eventually block the oil flow. Note the rod oil hole is not radial to the crank centre, It points toward the low pressure area, typically at right angles to the throw so a large through hole would give sludge a place to accumulate.
Allan, I am not sure that is correct - "It wouldn't work the same if you put a external filter in the feed line without either having that weight or pump pressure behind it." If an external filter is mounted not higher than the internal "Charles" filter the weight of oil above it is the same so the pressure against the element is the same. However, most external filters are not as large as the internal filter so there is less area for the pressure to work against. In that respect, you may be right.
The B25 single with its plain rod bearing does have a sludge trap in the crank journal. The B44 and B50 with their roller bearing rods do not.

B44s and B50s do have sludge traps.



Tom

BSA Gold Stars with their roller big ends don't have a sludge trap unless you count the small axial hole in the crankpin as one. It does actually trap debris but has very little capacity..

Sludge from the days before detergent oil and oil filters. When it dries out in there it looks like graphite. And hard as a rock.

What a nice day! Hit 48 F, would have taken a ride but yard work till noon. After lunch, noticed the sun was shining into my garage.

The must make repairs on stuff was all done.

Time to pull the scavenge trap on the A65 basket.

Phase one didn't work a few weeks back

Phase 2 with carbide cutter and drag link. Getting leverage with the vice. Don't try this at home kids.

30 inch breaker bar to the rescue. Calibrated arm estimated at 90 foot-pounds
https://live.staticflickr.com/65535/51871719482_2124c524c3_c_d.jpg
You can see the flywheel bolt tit stickin through.
Uh, what size did you say the flywheel bolts are?

The hex is .532 inch. Too big for 1/2" US of A. Too small for 9/16 US of A. 13 mm almost goes on but is a hair small. If I had to I would tap the 13 mm on with a small perswader. But I don't have too. Guessing a 17/32 US of A might be the ticket. But of course, its either Whitworth, BSF, BSC, one of those BS sizes which one I have no clue. Maybe i should check the manual; its around here somewhere.

If I read the charts correctly a 1/4W or 5/16 BSF socket would fit a 0.525" bolt head. I do not have a crank handy to measure to see what size I get.

Gordo

They are 3/8 BSC bolts with 5/16BSF heads as i remember.

Missed the unmarked piece in the exploded view, sorry.

yes , what Gordo and Nickl said .
its called out in the book as a 3/8 x 26 tpi bolt ... , but 3/8 is the shank , not the head ( across the flats )
... with the one size reduced head ,
takes a 5 /16 BSF wrench ... which is also 1/4 W .
  both are 0.525 " across the flats and the wrench/socket may
come marked with both

If you haven't got any Whitworth spanners/sockets and your working on an A65 you will need them, a late motor has a mixture of both and early ones are all Whitworth size heads.

Old spanners and sockets will say 1/4W 5//16BS, newer sockets will just say the Whitworth size.

I learnt about sludge traps the hard way. Back in 67 as a youngster I had my first second-hand Spitfire and one day while out riding I heard this faint knock from the motor which quickly got louder and louder until I stopped the engine. Yes, the trap was found to be completely blocked along with the journal drillings. I had no idea that the engine had such a thing, also I had just changed the oil with Filtrate 20/50 (that had colloidal graphite additive). It was too damaged to be re-ground so it was to be a new crank from the local BSA agents, £17.50! I can't remember whether that included a set of shells.

The manufacturers weren't bothered if the bike blew up, as long as it was out of warranty. They would sell another bike!
The only oil filtration needed a complete engine strip to service it, obviously it was going to get blocked up and fail

The OEM crankpins on a Gold Star had a removable slotted plug but all the aftermarket Alpha pins are plugged and would need to be drilled out.


Bill B...