Looks Like a Short Season

'75 MKIII <30,000 miles

400 miles on a new oil change and I found this. Anyone have any idea what would cause slivers like this?
Can't tell if they are chips or slices. I was wondering if the timing chain could slice up the guide like this, last time I looked the rubber was still intact (last year).



Pete

That's what I used to see in past Peel and first few oil changes in unrestored Trixie - before I got over the wet sump worry and follow comnoz advice with my own, push kicker down failry slowly a time or two to find compression then step down fast and let it roar straight over 2000 - to barely see or feel any sump fuzz at all. Its steel-iron that sticks to magnets so has to be from rings/bores, cam liters and a bit from the crank bearings smoothing out 'normally' so relax and keep rpms on up side of lugging is all- though if brave enough might try hobot horrible habit. Btw this is the size regualr oil filters are mainly designed to catch for oil passage clots but don't help much in our engines as ordinary filters mainly protect oil tank scrap collection.

Steve,
So you are saying this is normal with a engine w/ 30,000 miles? I recall seeing fuzz before, but I don't remember seeing the larger pieces. Normal cold start is 1 or 2 kicks and lock throttle to about 1,500-2,000 rpm, helmet gloves and then ride.

I don't know if I should buy an engine stand or a quart of oil.

Pete

That is not much. I wouldn't worry about it.

Maybe see what is in your oil filter too, before taking it apart. I didn't have a magnetic plug until last year on mine but I think it is just doing its job.

Looks a lot like my MK3 's magnetic drain from a few years ago. caused by a camshaft lobe and corresponding follower going south. I had a feeling this was the issue because one tappet (I think it was the left ex) was constantly needing adjustment. Gap was increasing while the others were not. Do you have abnormal gap increases? The relatively good news is that the bike continued to run fine and when I finally bit the bullet and rebuilt it, the cam, though not great, was not totally destroyed either. There was only a few thousandths off the lobe which is why it was running OK. You probably have at least this season to ride without problems.

Thanks everyone. Seeing how I found debris from last seasons oil and did not have any problems and I have at least 400 miles on this oil including a 200 mile trip yesterday including back roads, highway and some pretty good hills (your neck of the woods batrider). Bike ran good and strong even got caught in bumper to bumper traffic for about 15 minutes and idled perfect. I will hope for the best.

Biscuit
I will check valve adjustment and rocker lift. Last adjustment was about 1500 miles (middle of last summer) everything was good was within .0005" from prior valve adjustment (previous summer).

Pete

More than likely just normal non issue new engine break in swarf but entirely possible it means you about to blow your ankles or groin apart by flywheel exploding - but I'd just ride w/o another thot about it till something more revealing shows up. Seriously even if lobe/lifter chiping so what - its not any evidence of bad show stopper for normal length of Commando endurance. Might try an oil fill interval like hobot - go straight to cam break in rpm+ till ready to slow it down an instant engaging clutch to leave safely.

Just a reminder that valve rocker arm clearance is set when the valve is fully shut, so the cam will be on it's base circle.
Clearance adjustment shows that the valve seat faces in the head are wearing.
The typical wear to the cam is on the top of the lobes so you will need to check how far the rocker pushes the valve stem down.

I'd agree that shiny steel flakes in the oil may be wearing cam/follower bits.

Bob Z. said:

Just a reminder that valve rocker arm clearance is set when the valve is fully shut, so the cam will be on it's base circle.
Clearance adjustment shows that the valve seat faces in the head are wearing.

Click to expand...

Definitely agree that wear on the cam lobe wouldn't show up in a lash clearance check, but would you not also expect to see similar wear on the cam follower? This would show up as a steadily increasing valve lash clearance. Assuming the cam lobe and follower wear around the same rate, of course...

Nathan

Nater_Potater said:

Bob Z. said:

Just a reminder that valve rocker arm clearance is set when the valve is fully shut, so the cam will be on it's base circle.
Clearance adjustment shows that the valve seat faces in the head are wearing.

Click to expand...

Definitely agree that wear on the cam lobe wouldn't show up in a lash clearance check, but would you not also expect to see similar wear on the cam follower? This would show up as a steadily increasing valve lash clearance. Assuming the cam lobe and follower wear around the same rate, of course...

Nathan

Click to expand...

My plan is to set up a dial indicator on top of adjusting screw and either:
zero lash adjuster and check for total rocker travel @ valve or
measure total rocker travel @ valve and adjust for actual valve lash and
then compare all four to each other or at least intake to intake and exhaust to exhaust

This is all new territory to me, so it will be trail and error for a while until I get my head wrapped around it.

I am trying to find what the rocker travel is at the valve for a stock MKIII cam. I believe the total lift @ the cam is .310" but i am not sure what that translates into rocker travel @ valve. I think the rocker ratio is 1:1.5 so the number should be either .465" or .155". At the moment this part is pure speculation.

Pete

opps i slipped a cog here.

Cam seat wear or recession as well as valve head wear will show up as reduced clearances and I don't believe put that kind of swarf on the magnet. As far as lobe or follower damage is concerned, whichever one starts to fail first, (most likely cam I think) the other will be dragged along as collateral damage. And that follower wear will show up as increased clearance. Whatever may be worn off the lobe would not be measurable with a feeler gauge of course but if the valve opens and closes pretty much like the others using just your eye as gauge, I'd just enjoy the season and budget for rebuild next winter. (Yuck, I said "winter").

Hi Deets55.
It is not cam follower face as that is stellite (a cobalt alloy and not magnetic), nor bushes (bronze), nor piston (alloy).
It has to be iron or steel so just think your way through any of these components in the engine that it could possibly be e.g. do you know what type of bearing cage is in your bearings? or cam chain tensioner wear to metal as you suggested? Maybe cam? etc, etc. Some you can test for and others you will need to open up to look.
Ta.

It has to be iron or steel so just think your way through any of these components in the engine that it could possibly be e.g. do you know what type of bearing cage is in your bearings? or cam chain tensioner wear to metal as you suggested? Maybe cam? etc, etc. Some you can test for and others you will need to open up to look.
Ta.[/quote]

Needing,
MKIII's have a window to check the timing chain tension I was able to look though it. From what I saw chain tension was correct, I could see no damage on the chain and the rubber pad on the tensioner was intact. I believe that engine also comes with high quality bearing from the factory and are pretty sturdy. I do not feel any (extra) rumbling or vibration. I am leaning toward cam or rocker adjusters (Comnoz's suggestion). I won't be able to check again to Wednesday or Thursday. On a positive note there was nothing in the sump filter 400 miles ago (even thought there was some stuff on the magnet), and the bike does not wet sump so I don't think the pump is messed up. It held all it's oil for about 8 weeks and never moved on the dip stick. If I get good lift on the rockers and the adjusters look good I am inclined to call it "wear" and monitor the magnet every couple of hundred miles. Tough call to make. I know right off the bat the exhaust will probably never come apart easily, if at all.
Pete

needing said:

Hi Deets55.
It is not cam follower face as that is stellite (a cobalt alloy and not magnetic), nor bushes (bronze), nor piston (alloy).
It has to be iron or steel so just think your way through any of these components in the engine that it could possibly be e.g. do you know what type of bearing cage is in your bearings? or cam chain tensioner wear to metal as you suggested? Maybe cam? etc, etc. Some you can test for and others you will need to open up to look.
Ta.

Click to expand...

The swarf itself can't be follower material but still the stellite can be getting beat up from the cam. The two will eat themselves up but only the cam lobe material will stick to the magnet.

>> I know right off the bat the exhaust will probably never come apart easily, if at all.<<

I don't see a crossover pipe so if that is the case the header and silencer come off as one piece so not a problem.
Are you referring to getting the header nuts loose?
I'd loosen when head warm.

rx7171 said:

>> I know right off the bat the exhaust will probably never come apart easily, if at all.<<

I don't see a crossover pipe so if that is the case the header and silencer come off as one piece so not a problem.
Are you referring to getting the header nuts loose?
I'd loosen when head warm.

Click to expand...

Original exhaust with balance tubes. Last time is was touched was probably 20+ yrs ago. When I had it off right side side flange was cracked and worn thin. Exhaust nut must have been a little loose and vibration got to it. I fit it in with high temp permetex and it think the split collar.

Pete

Deets55 said:

rx7171 said:

>> I



Original exhaust with balance tubes. Last time is was touched was probably 20+ yrs ago. When I had it off right side side flange was cracked and worn thin. Exhaust nut must have been a little loose and vibration got to it. I fit it in with high temp permetex and it think the split collar.

Pete

Click to expand...

Click to expand...

Yikes! on the exhaust nut you used the permatex?

Check the rocker spindle thrust washers. After a lot of years and/or miles they become very thin and start flaking.