I purchased an 81 300sd for a couple of hundred bucks recently. I dropped the oil pan and found a blown apart roller bearing, and a couple of other chunk of metal. I inspected the timing chain, and the part of the crank visible with just the lower oil pan removed. Neither showed any visible sign of damage. I am able to crank the engine by hand. I do not feel any binding or hear grinding. It does feel as though the cylinders are making compression when hand cranking.

I also removed the Valve cover and did a valve adjustment. 5 out of 10 were a bit tight, and were adjusted accordingly. All the lobes showed no sign of scoring, wear or damage. Being that this car is close to 200k, the timing chain was tight and looked very good.

The inside of the valve cover sowed signs of metal contact. Looked like jagged etchings

Where could this metal have come from? I don't know where there is a roller bearing or where these other large random chunks may have come from. I have yet to try and fire the engine up, and glad I have not.


Any help or insight on where to look or inspect would be greatly appreciated!

vac pump?injection pump? don't fire up motor till you know

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

May be from a previously failed vacuum pump and then the chain was replaced. Perhaps the previous owner would know.

Pulling the vacuum pump to inspect the roller bearings would be a good place to look.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

It may be possible to lose the vac pump and the parts not get stuck in the cam chain. Have you examined the vac pump?

What is the third picture of....inside valve cover?

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

The third pic is of the the valve cover. I found an outer race of a roller bearing up there when I removed it.

I will be pulling the Vac pump today to give it a look.

This car had been passed around to bunch of the high school boys out in the country, then parked on someones property. Before that, it would appear someone was taking good care of it. The kid I got it from didn't know much about cars, or its history. He only said it ran, but the tranny wouldn't down shift. I did find the vac lines for the transmission mostly missing, and the rest leaky and routed incorrectly. It was so cheap and the body I wanted I wasn't going to pass it up! Hopefully it doesn't mean a new engine.

Edit: I could see this being from an older failure. The oil pan was bent in a way that these chucks couldn't have drained out of the plug, and were deep in a thick sludge at the bottom of the pan. When I first drained the oil I didn't notice any metallic powder in the oil.

There are two ways to link the timing chain together on a roll-in replacement, with a c-clip or a pressed link. Look closely at the chain for a c-clip, if you find one you know the chain was replaced. A proper crimp would be hard to find even if the chain was replaced. Remove the vacuum pump as stated for inspection.

What color are the chain guides? If beer bottle brown they need to be replaced. If not then they were probably changed and the chain replaced.

Good luck...make it live again @ 200k it's not warmed up yet!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I got the Vac pump removed, and all the roller bearings were intact, and undamaged. I couldn't see any physical damage on the unit, just a little rust here and there. I removed the Valve cover again to inspect the chain. The chain does look shiny and relatively new. However, at least one of the chain links has been damaged. This was probably from the outer roller bearing race I found under the valve cover.

Did I dodge a bullet here? Could one of the previous owners replaced the chain and pump, leaving the old metal shards in the engine, causing the new chain to become damaged?

Guess Ill add a timing chain to the list! are there any other components that could dump roller bearing/ chunks of metal in the pan? The strangest piece is the cylinder with a small ID from the first Pic I uploaded of the debris.

Ill try to post a pic of the chain and Vac pump

I believe that large cylinder is the center runner, between the two roller bearings inside the vac pump, that actually rides on the lobed plate attached to the timing chain.

This must have been from a previous failure. I found black RTV on the Vac pump interface. I could not find a C clip on the timing chain. But I only went through it quickly once. As far as I could see there is only damage to the one link I attached above. Ill be replacing the chain.

I think this motor has two chains, the one you see and a lower one for the oil pump. Check them both for damage.

How does the roller surface that the vacuum pump rides on look?

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

That chain looks to have had contact with some part from a failed vac pump. The small cylindrical pin looks like it held on one of the parts in the vac pump. Balls look right size too.

Clean up really well, I'd want to pull the motor so I could clean everything really well. I'd really want to check the bearings for fragments.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Okay so I'm pretty sure the bushing on the shaft that drives the roller-coaster cam, for the vac pump, needs to be replaced. I can not find this bushing anywhere.

Does anyone have a link for where to buy this bushing?

Thanks for the help!

Call the number at the top of the forums, they can get anything

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$60 OM617 Blank Exhaust Flanges
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No merc at the moment

Thank you! I'll give them a call!

I lined the cam tower marks up, and the dial on the crank was showing about 18 degrees out. I did a little marking test, and it appears to be equivalent to one tooth on the cam sprocket. Based on the fact that one of the previous owners likely replaced the timing chain, it seems likely that they jumped a tooth during the installation.

If I am able to lock down my split timing chain, am I able to just move the cam sprocket one tooth back, realigning the cam marks with TDC?? My other concern would be that the fuel pump timing could likely be off if I am able to successfully move the cam sprocket without chain movement. How would I be able to re-time the fuel pump??

Thanks for the help!