Hey lets play "Where did this ball bearing come from?" - PeachParts Mercedes-Benz Forum

Johnhef · #1 12-03-2008, 11:08 PM

So I finally got around to taking this 1990 560SEC engine I bought for parts off eBay a few years back. When I pulled the passenger side head off, I found out why the engine was scrapped!

See the round indentation in the bottom of the head?

and the indentation where I found the ball bearing sitting when the head came off.

and theres the damage to the block. Piston was broken underneath and cracked on top, when it tried to compress the bearing, the bottom part of the piston pushed out on the wall of the cylinder and broke it.

I'm still wondering where it came from and how it got in there in the first place!

duxthe1 · #2 12-04-2008, 12:20 AM

My only guess is that it is the factory plug for the Lambda adjustment tower. Nothing else even remotely near the intake could have produced that barring intentional sabbotage.

mytmousemalibu · #3 12-04-2008, 12:46 AM

ball from a bad water pump? If the intake system had to be partially removed, someone could have dropped one out or set the pump down in a bad spot and it fell out? Could be from some other pulley or tensioner or etc. too. Im a Bimmer tech and i could see that happening pretty easily. One thing ive seen most is a spark plug comes apart and the center electrode falls in the cylinder and does damage.

Johnhef · #4 12-04-2008, 08:15 PM

This thing doesnt appear to have bounced around, just right into the corner and boom. possibly on the first crank, the piston was still all the way up pressing the bearing into the head untill I removed it.

cheapold280ce · #5 12-04-2008, 09:29 PM

My guess Pissed off EX (girlfriend, wife, lover etc) drops on the air meter plate. Or pulled a sparkplug and drop one in.

79Mercy · #6 12-04-2008, 09:56 PM

Cheapold, unless you have a girl that knew about cars, I doubt that would be the case.

Arthur Dalton · #7 12-04-2008, 10:07 PM

Quote:

Originally Posted by 79Mercy

Cheapold, unless you have a girl that knew about cars, I doubt that would be the case.

Girlfriends ex -Boyfriend/mechanic.......

Benz Mercedes · #8 12-05-2008, 07:11 AM

It could only enter through the spaces large enough,... the spark plug hole, obviuosly before the spark plug was inserted, as it does not appear that the head was off recently.. the only other way.

Ben

tinypanzer · #9 12-05-2008, 07:52 PM

Looks like a steering gear bearing....

Weird.

Only thing I can think of is that it entered through the spark plug hole. I don't see the intake valve opening far enough to sneak that bearing by.

So..... Major tune up in progress, all spark plugs removed. Somebody pulls out some other part like the water pump or or some pulley, and it spills its bearings. One of them just happens to fall down a spark plug well in ends up in the cylinder.

The only other thing I can think of is somebody put it in there to sabotage a fellow employee at a shop, or it was was done to kill the motor while it was still under warranty.....

-tp

Matt L · #10 12-05-2008, 09:28 PM

What is the valve lift on that? There might be enough clearance through the intake valve.

Technically, that's a steel ball. A "ball bearing" is a bearing that uses balls, usually steel balls.

david s poole · #11 12-05-2008, 10:18 PM

looking at your photos that is the ball that was used to seal the fuel adjustment tower.does the tower look as though it has been cut or do you not have the intake with the fuel plenum?if someone took a hacksaw and cut the tower from the front and overlooked putting a rag or otherwise blocking the air intake.if you cut just right the ball will pop out,i have seen it.

Johnhef · #12 12-05-2008, 10:32 PM

Thats definitly possible, the plenum was still there, although now buried at the bottom of the box of parts- I'm not sure if the tower was still on it or not.

The car had 88K showing on the odometer when I went to pick the engine up. The seller (the mechanic) said they brought the car to him with a replacement engine and just said "replace it" so he didnt bother diagnosing it.

t walgamuth · #13 12-06-2008, 05:37 AM

Its an interesting question. Its big enough it is questionable whether it could fit past the intake valve.

I once ruined a perfectly good freshly rebuilt cadillac motor by dropping a stud down into the intake. I had often used the trick of dropping a screwdriver into the spark plug hole and turning the engine by hand to determine tdc to time the dist.

So one day when I was trying to work on the car when I was in a mental state where I probably should have done something else (one of my favorite uncles had just died and I think I was more affected by it than I realized. I needed to locate tdc and no screwdriver was handy so I used about a four inch stud.

It was just long enough so that later when I decided I needed to crank the car with the starter it dropped into the cylinder and when it cranked over it simply punched a hole in the piston. Dumbly not realizing what had happened I went ahead and started the motor and when it had a dead miss on one cylinder I shut it off... but the debris from the piston by then had been picked up and wiped on all the bearings.

So I had to pull it and have it redone all over again.....Ouch!

I am not sure if its the most expensive automotive mistake I ever made but its for sure in the top three or so.