what's this in my sump?

[tedlit]

So after much gnashing of teeth (and a still-seized track arm bush - how on *earth* do you get those out?), I finally got my sump off. I found about half a pint of thick brown sludge, a mostly-blocked oil pickup, and these:



(the numbers on the lower big say 144799 STD KGV E)

Now, I'm not much of a mechanic.. I can change a gearbox and deal with Lucas electrics, but engine internals I tend to leave to the rebuilders.. but these two things look an awful lot like thrust washers to me (my other Triumphs are 2500's, which are famous for spitting their thrust washers into the sump).

There were only two in the sump.. the lower one in the picture has no wear markings whatsoever on it and is maybe 2mm thick, and the upper one is about 0.5mm thick and very badly scored on both sides.

So... what have I found, and should I be thankful there weren't hundreds of tiny metallic pieces instead?

[mad cyclist]

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they go between the bottom of the big end and the crank don't really want them floating about really! do you habve a knocking noise by any chance?
rgds Nick

[tedlit]

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Sortof.. nothing to write home about though.

The reason I'm in the sump in the first place is to see if I can figure out why I've got such pathetic oil pressure.. after confirming it's not the pump, I suspected worn main bearings (engine's got a supposedly genuine 67k on it).

[Guest]

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These are crankshaft thrust washers.I bought a stag once that that had a crankshaft end play of .067 instead of .006 t0 .080 (hope I have got that part right). Took the engine apart and found that the previous person that had rebuilt the engine had put these thrust washers in the wrong way around. The con rod and crank shaft were only good as a boat anchor.

The sludge in your sump is probably a result of the oil not being changed on a regular basis

Dave L

Toronto

[tedlit]

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The end play in my crank is around 1mm - with the thrust washers on my garage workbench, obviously. When I very first bought the car, the play was around .03mm, so I'm guessing at that point at least one of the washers was still in place.

It looks to me like the washer *was* fitted backwards - the wear is on the side without the vents cut in. The other washer piece has no wear marks on it anywhere, so I'm guessing it fell out without ever being used.

Something I don't understand.. and forgive me if this is a little simplistic.. but what holds the thrust washers in place? The factory manual (and the Haynes book as well, actually) both just refer to 'removing' and 'inserting' the thrust washers either side of #3 main... but no indication of anything else that has to be done. I can't see how they can just stay in place on their own!

(Like I said.. dodgy electrics is much more my forte. )

[V Mad]

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I think the thrust bearings fit into a shoulder so they should get trapped when you put the main bearing cap on.

[Sheepdip]

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Correct, they fit both sides of crank and cap keeps them from turning. The cutouts should face the crank to allow oil flow.

A Triumph problem, they are rather thin and can drop out if badly worn, probably more of an issue with manuals as the thrust puts more pressure on them [a 1300 I worked on, engine would happily run but stalled when clutch pressed].

I assume this previously happened on mine as the block had been repaired and still happily runs (albeit an auto). I wonder if the crank can be refaced to save it?

[tedlit]

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Excellent, thanks for the tips guys.

One final question.. could the lack of thrust washers be anything to do with my low oil pressure? I would've thought not.. especially as the upper end lubrication still seems OK.. but you never know.

[Sheepdip]

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Its possible if the thrust washersor thelack of have chewed the bearing.

The only way to check is to remove the cap. You've removed the sump so easy to remove the center cap and check (2 bolts). Wiggle the cap off and 1/2 the shell bearing comes with it - it should be a smooth dull grey colour (the other half is in the block, held by the crank which will be shiny and smooth). With the cap off the 2 slots in the block for the thrust washers will also be visible. I'd suggestmicroscopicattentionto this area, the thrusts may have worn the block/crank, not nescessarily a simple case of new ones I'm afraid.

Good luck

[GDPR]

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I hope you don't do what some animal did to one of my dolly Sprint engines..... the thrusts had dropped out on this block and the newly increased crankshaft endfloat had chewed up the block and main cap where the thrusts go...... so the ******* drilled, tapped and screwed new thrusts into place......:shock:

Might have been OK if he had loctited the screws...... you can guess what happened...

Luckily at the time I'd bought a couple of brand new cranks, from BL at £28 each as part of their stock clearance, but had to scrabble about for a decent block even then...

Russ

[Sheepdip]

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kryten wrote:

I hope you don't do what some animal did to one of my dolly Sprint engines..... the thrusts had dropped out on this block and the newly increased crankshaft endfloat had chewed up the block and main cap where the thrusts go...... so the ******* drilled, tapped and screwed new thrusts into place......:shock:

Might have been OK if he had loctited the screws...... you can guess what happened...

Luckily at the time I'd bought a couple of brand new cranks, from BL at £28 each as part of their stock clearance, but had to scrabble about for a decent block even then...

Russ

Thats unfortunate, perhaps the intention was good but a lack of care to the detail. Whoever did mine fitted a bronze thrust toone sidewith a couple of bronze pegs, taking up the slack with a proper thrust on the others side, works fine.

[tedlit]

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kryten wrote:

I hope you don't do what some animal did to one of my dolly Sprint engines..... the thrusts had dropped out on this block and the newly increased crankshaft endfloat had chewed up the block and main cap where the thrusts go...... so the ******* drilled, tapped and screwed new thrusts into place......:shock:

Ouch!

Granted, I've no idea what state mine's actually in yet.. but if it looks like it needs block or crank work, I'll yank the whole thing out and get it rebuilt properly. I've got another Stag that just needs the interior fitting to make it driveable, so I'm in no real hurry.. as is evidenced by the fact that it took me six months just to get the sump off

[Ian F]

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Tedlit - last issue I had with Triumph thrust washers wasn't a Stag but a Spitfire. Thrust washers were so worn they revolved with the crank, ground a lip in the main bearing cap that was supposed to retain them and (I was told) effectively bu**ered the engine as you could not fit another main cap - they were line bored?

I put another short engine in it, it lasted 12 months and the same thing happened again!! Too young, thrashed it too much or didn't change the oil often enough I know (It was 30 years ago!). The fault manifested itself in a clutch that would not clear properly due to the end float - gawd knows what it did for the piston and conrod alignment. Hope yours is not as problematic!

Ian F

[flying farmer]

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I have seen this thrust washer problem on several triumph engines. There is a good possibility that the thrusts have been installed back to front. I purchased a non running engine for spares and found the thrusts had been installed back to front. The rear one which does all the work had worn to half thickness but had not actually fallen out. Fortunately the crank had been well hardened and it had not damaged the thrust area because I am using this crank on another engine I am building.

If the crank has only worn into the bearing cap and not eaten into the machined area of the block, I have managed to save the block by having the edge of the main bearing cap built up with weld then filed to size to retain the thrust washers. This was on a 1300 engine but the construction and principles are the same. One of the greatest thrust washer killers is starting the engine with the clutch depressed

Neil

[tedlit]

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OK, this next bit's not for the faint of heart. I took #3 main bearing cap off this morning. While the bearing shell itself looks fine (evenly worn, slight uniform bluish tint), I can't say the same for the cap:



...and just in case that's not clear enough:



This truly horrific wear is mirrored on the block face also.. it looks to me like the thrust washer's been spinning around in there for a while. I know this car was last on the road in 1986, and I always assumed it was taken off the road for bodywork.. perhaps not, eh?

The crank, ironically, is completely unscored - if it is worn at all, the difference isn't measurable on a vernier gauge.

So it looks like my block is toast