Spark plug hit by piston, valve? M103 engine - Page 2 - PeachParts Mercedes-Benz Forum

ILUVMILS · #16 12-02-2007, 11:47 AM

Quote:

Originally Posted by Tony 12

Maybe a bit of an 'out-there' suggestion, but is it possible that the spark plug was knocked while in the head but off the car,

Quote:

Originally Posted by Chas H

I think the damage was done while the head was off or there was something foreign in that cylinder.

When I saw the picture of the damaged spark plug, this was the first thing that came to mind. The more I think about it, the more sense it makes. That's why I asked if the plugs were installed for the duration of the job.

If there's any doubt about a foriegn object in the cylinder though, there are a few things you should do before installing a new plug and starting the engine. Using a borescope would be ideal, but since that's not gonna' happen, try this (I'm assuming you have an air compressor). Connect a piece of rubber vacuum line to an air nozzle. Put the vacuum hose into the cylinder and blast away. Keep a close eye on the spark plug hole to see if anything comes out. This may not get everything out (if there's anything in there), but you'll know right away if there's a problem. I've used this trick many times to clear debris from OM606 diesel cylinders, after drilling out stubborn glow plugs.

Quote:

Originally Posted by Hatterasguy

Well you must have gotten the timing off, I'd start by timing it.

Not sure what the chain drives on an M103, but getting the crank and cam on the timing marks would be a good start. Is the distributer driven off the chain?

Incorrect engine timing can't cause piston-to-plug contact. Piston-to-valve? Yes. Piston-to-plug? No

As for the distributor, the ignition rotor is driven directly by the camshaft.

Ron in SC · #17 12-03-2007, 06:49 PM

Thanks to all who have been kind enough to offer me advise and suggestions on how to deal with my situation.

Well, from reading and thinking about situation I decided I must have managed to get something in the cylinder that should not be there and the only way to know for sure and to assess damage was to remove head. So I did that.

Piston, cylinder and head and valve seat where damaged. The damage was caused by the small breather hose that goes from the intake manifold to valve cover which has those two metal clamps. The clamps did the damage. It is apparent I was not careful enough when fit the head to the block. This is the first time I did a head gasket replacement, so anyone else who does one for the first time I'd have to recommend just removing that little breather hose when you fit the head to the block, I suspect the pros remove it or are just more careful.

I do have a parts car, 1992 300 E with about 15K less miles on it than the engine I ruined in the 1992 300 TE. So everything should be the same except for the tandem power steering pump on the TE which runs the self leveling system.

I'm wondering if the transmission for the E model is the same as the one for the TE.

Hopefully I can swap engines without screwing anything up. I'm not a professional mechanic but I've got a good bit of experience and feel pretty stupid for not being careful enough when I reintalled the head.

ILUVMILS · #18 12-03-2007, 08:28 PM

Dude....I feel for you. I've made plenty of mistakes over the years, so I know how you must feel, but don't sweat it. Maybe there's hope. What kind of damage did you find? If the piston didn't crack, the damage may be limited to the cylinder head. If so, it's possible it can be repaired. If a valve seat didn't get hammered it might be easier than you think. Don't make a bad situation worse. Assess the damage and proceed accordingly. Keep us posted.

t walgamuth · #19 12-03-2007, 10:45 PM

I would get an experienced machinist to look at it. Sometimes things aren't as serious as we hobbiests think by looking at it.

Good luck.

Tom W

Ron in SC · #20 12-04-2007, 11:04 AM

Attached are photos of my mess. Note cylinder is scored.

lee polowczuk · #21 12-04-2007, 11:42 AM

ron...there was a guy on here selling a head that he rebuilt.... i think he was looking at 350 shipped.

I know i was very interested in it.... but just don't want something that big taking up room.

his name is hihosilver

ILUVMILS · #22 12-04-2007, 12:27 PM

Oh well. I think it's time to go with plan B. Best of luck.

Old World Auto · #23 12-04-2007, 12:32 PM

Ron,

Mistakes happen to everyone. I installed a cam timing gear backwards on my old 220Sb and drove the car for half a semester in college before it reared its ugly head. We all have our stories. In the future, I am sure you will ensure the bores are clear of any debris. Chalk it up to a learning experience.

Looks like your cylinder head may be salvageable, but that is a nasty score in the block. If your spare motor is nice, looks like it will be the best way to go.

Ron in SC · #24 12-04-2007, 02:10 PM

My spare motor will come from wifes 1992 300E with 135k miles on it. We have had that car from about 9 years having bought it with 60K miles on it. The car was totaled earlier this year when it was hit from behind, really not much damage but trunk lid will not close.

The 1992 300 TE was purchased about 2 years ago with 133k miles on it. I basically restored it, everything worked perfectly including the new evaporator which I changed out shortly after I bought it. The wagon had it's original head gasket replaced once before but I don't know at what mileage. I had even changed valve stem seal which stopped it from burning any oil.

I'll need to figure a plan for removing the engine, i.e., the block.

I would kind of like to reuse the intake manifold and fuel distributor and associated fuel stuff.

Should I start taking assesories off what remains until there is nothing but the block to take out of car?

Old World Auto · #25 12-05-2007, 11:11 AM

[QUOTE=Ron in SC;1693584
I'll need to figure a plan for removing the engine, i.e., the block.

I would kind of like to reuse the intake manifold and fuel distributor and associated fuel stuff.

Should I start taking assesories off what remains until there is nothing but the block to take out of car?[/QUOTE]

Ron,

I would suggest you remove motors as whole assemblies, swap bits around as you like with the motors out of the car, then reassemble. Also with the motor out, it is an ideal time to clean the motor as well as the engine bay, replace any seals, gaskets, etc, that would benefit from such. With the motor out of the car, things become considerably more accessible and simpler to work on. Make the most of the opportunity so that you do not have to dive back in there for a long time to come.

Ron in SC · #26 12-06-2007, 04:05 PM

I would suggest you remove motors as whole assemblies
Would that include the transmission too?

As far as the wiring harness goes I've removed most of the connectors on top of the intake manifold. Do I remove the harness connectors under the engine and leave the harness with the body of the car or do I disconnect it from behind the battery?

The motor that will go in wagon had head gasket replaced at 101K miles and waterpump at 81K miles, motor now has 135K miles so I should be ok with that. It also has a new mercedes a/c compressor installed just a few years ago.

t walgamuth · #27 12-06-2007, 04:28 PM

If it is a known good tranny attached to the motor you are going to use I would keep it attached and install as a unit. That way you are not disturbing the seals around the torque converter.

Sorry it turned out so badly.

Been there, done that too.

Tom W

Johnhef · #28 12-06-2007, 09:53 PM

exactly, If you're planning on doing this in your driveway, i.e. on your back, pull the engine and trans as one unit. Use a load leveler so you can tilt it to clear the core support! As I started reading the thread I was going to guess one of the guide pins got into the cylinder but I guess those hose clamps can be just as nasty!

lee polowczuk · #29 12-06-2007, 09:56 PM

ron... are you really going to attempt this yourself?

Ron in SC · #30 12-07-2007, 10:12 AM

Quote:

ron... are you really going to attempt this yourself?

Yes, that's the plan. Of course it's subject to change. My new detached garage is not completely done and lift is not in so I may have to have my friend who owns MB shop lift motor out of donor vehicle and place it into wagon. I can for sure remove motor from wagon and transmission if necessary. I can do all the other stuff.

I don't have a lot of time to work on car because I'm doing finishing type work on the house addition and then I'd like to get back on garage (photo below) to do painting and other work to finish it up. Basically the engine change project is not the highest of priorities.