Shrapnel in Sump

Status
Not open for further replies.
So here’s an embarrassing story. Several years ago, I built a 71 Triumph Bonneville – every nut and bolt. The bike ran great and I had it out for several miles testing. When I was happy, I planned to take it out to a field for pictures so I could list it for sale. Gave it a kick and the lever went down about half way and jammed. After fooling with it for a while, realized than the engine was seized. I was shocked and confused – I’ve built many engines and never had anything like that. So, I started taking the engine down to see what happened. Primary off, noting wrong there and the gearbox was free. Rocker boxes off – all looked good. Cylinders off – cylinders, pistons, rings – all good. Rods moved smoothly on the big ends but the crank wouldn’t turn – main bearings? As I started to lift the engine from the frame, the crank turned – weird. On a whim, I turned it upside down and a ¼” x ¾” bolt fell out! Took the cases apart and found only a nick where the bolt had jammed the crank. Put it all back together and everything was fine.

Fortunately, it didn’t catch with the engine running! To this day I have no idea how that bolt got in the engine. The engine was built on the workbench in an afternoon with no one around but me so somehow a bolt got in there that had nothing to do with the engine.

To me, it’s simple. Something broke in your bottom end or that part has been there since the engine was built. If it were mine, I would take it apart and figure that out. The thought of an engine seizing at speed dictates it for me! It may be the picture, but it looks thick. The only steel I can think of in a Commando engine that might be that is a piece of a main bearing. But, since it looks like something that doesn’t appear to belong in a Commando engine, I’m betting that it has been there since the engine was built.
 
Daft suggestion, but are you sure it was on the magnet when you took the plug out. No way the debris could have attached itself to the magnet outside the engine, e.g. from prior use of your waste oil container?
 
oldmikew said:
I wonder if it could conceivably have got through the pump gears?
Click to expand...
Tornado said:
At nearly 3mm wide and curved, I'd struggle to see how it could get through the pump.
Click to expand...

I seriously doubt it could have gone through the pump because it would have to be the feed side and not only would something that size and shape have been severely mangled or chopped to pieces in the process but would then have had to pass through the crankshaft and out of one of the big ends to reach the sump plug magnet!

It couldn't have gone through the scavenge side as it was found attached to the drain plug magnet so hadn't got that far (and couldn't due to the sump strainer), therefore, I think that any suggestion of it passing through the oil pump can be ruled out.
 
I once found a Crescent wrench in the oil pan of an engine we were working on. The engine was running just fine...

Admittedly, there's plenty of room for a wrench in an oil pan as opposed to the sump of a Commando. But, as others have said, it's quite possible that the piece of washer, shim or whatever has been there a while and came from something OTHER than a component failure within the engine.

Frankly, I'm not sure what I'd do. Of course, the only way to be sure is to disassemble the engine but if the engine is running as well as it always had, with no apparent change, I might tend to do whatever relevant checks I could without disassembly and, absent finding anything untoward, just ignore it. ;)

OTOH, if I had removed that sump plug previously and it had been 'clean,' whereas this time that piece of metal was there, then I'd start disassembling...:(
 
I too have looked through the AN exploded drawings for something that this could be and have found nought.

Like Glen, I’m not sure what I’d do, but I tend to think I’d strip it. I know I’d always be listening, thinking, worrying... A bit like this…

Shrapnel in Sump
 
I think atthe end of the day it depends on the kind of riding you do... if you are quick on the road and rev the engine out then for peace of mind partially strip the engine...on the otherhand if you cruise along rarely exceeding say4,000 revs , then iwould not bother if the engine seems tobe otherwise ok.
 
The remains could be a fragment of your d/s roller bearing cage. Some bearings had steel cages, some brass. As you won't be able to inspect by a bore scope due to proximity of crankshaft, I think you should gear up for a tear-down.

-Knut
 
Last edited:
Looks like Cliffa has nailed it - look at the section at 5 o’clock in the photo where it doglegs. Likely someone didn’t stuff the case mouth when removing barrels .
 
Coincidentally, "about 0.023" thick" would be the thickness of an oil scraper rail and if worn could be 0.114" wide although the radius looks less than expected for it to be part of a scraper rail.
 
I think in all likelihood it was dropped accidentally through the case mouth in the past while disassembled. It may very well be that presently the rockers are complete with newer Thackeray washers - the broken one being the reason they were replaced.
 
Fast Eddies cartoon hits home...every time you go out that little piece of shrapnel is going with you.
 
Mart UK said:
Daft suggestion, but are you sure it was on the magnet when you took the plug out. No way the debris could have attached itself to the magnet outside the engine, e.g. from prior use of your waste oil container?
Click to expand...
Yes it was there as I withdrew the plug, I did not let plug fall into my pristine catch container.
 
L.A.B. said:
You've quoted the dimensions in inches but the scale in the picture seems to be mm/cm as 0.114" wouldn't look anywhere near as wide on an inch scale.
Click to expand...
Yes the calipers were for thickness and radial width, the Metric ruler was just for a rough length to give things some scale. Thinking was most of folks here work in the "good Christian measures" (as Mr. Hemmings once exhorted to me over the phone :) ) and these might help better ID the flotsom.
 
cliffa said:
Sprung steel by the looks of it, so I would say it's the remnants of a rocker spindle Thackery washer or circlip but as L.A.B. mentioned it depend on what scale that rule is.

View attachment 81923
Click to expand...
I have some spare thackers from my head rebuild work, as I replaced all with new. Will pull one out and confirm. Will say the bit is quite stiff, I cannot easily bend with fingers and I did try to squash it flatter for measurements using hand pliers...no flattening could be done.
 
Status
Not open for further replies.
Back
Top