What a disaster, complete destruction........
 

Well I posted on sunday about a plume of white smoke out the back of the car, and oil all over the engine compartment on my 1988 190e 2.3 8v. Finally after fighting all week to remove the head(my first time), I see whats wrong. My #3 Piston is partially melted to the head, and has a huge gaping hole in the middle of it. I can see, what I think is, the crankshaft through the middle of the piston. What causes something like this to occur?

I guess its either time to say goodbye to mercedes(for now), or get a used engine to put in. A buddy of mine has an engine lift and says we can do it, but there is so much stuff under the hood I just feel overwelmed by the thought of this kind of project. I cant be without the car for very long, I am only borrowing someones to use right now, so I need to act quick. [B]MarekW[B] has kindly posted a list of used engines for my vehicle, on my last post.

Feel free to give me any encouragement or persuasive comments to try and get me to switch out the engine and keep the benz.:)

Two things jump to mind.

Jumped timing chain punching a valve through the piston top or a serious case of pinging.

How do the valves look and what octane did you normally run?

An engine swap really isn't as big a deal as it may seem. And if your friend has an engine hoist it will be even easier. (i just pulled the engine on my Miata without a hoist. -No biggie.)

Get a good used engine.
Get a repair manual that describes the operation. (Haynes or whatever)
Buy whatever stuff you may want to replace while the engine is out. (Engine mounts, cooling hoses, vacuum hoses...)
Get a friend (preferrably one with a little mechanical skills) to assist you.
You could swap the engine in less than a day, but plan on using a whole weekend since things like this always takes more time than planned for.

When you are done and everything works, you will not only have a lot more knowledge about how your car works, but you will also have a great feeling of accomplishment . -Hard to explain but you will know what i mean when you get there.

Good luck.

Freestyler

I know this is insane but...what would happen if a connecting rod and pison is removed (once the oil pan is lowered) and the valves are welded shut with stems cut so they don't contact the cam. How would such a 6 (or 8 cylinder engine) run assuming that all the other parts of the engine are functional? I wonder if this would make it even as a last ditched solution in 3rd world?

Probably a stupid idea even if it didn't cost anything besides gaskets and wasted time.

I did hear a story of a guy who bought a 6 cylinder Triumph that was running rough. He found that one cylinder had a piece of wood instead of a sparkplug. When he put a plug in and started the engine, it blew up. Not only was the plug missing, but also the piston and conrod! The mixture filled the crankcase and then ignited...

Have you checked the price of a single piston? (from a re-con specialist or parts supplier)

If the valves seal, and everything else is ok, this will almost certainly involve the least work. Probably the cheapest option too.

thanks for the replies,

Mike, the valves for this cylinder are covered in melted metal and i always used 91- 93 octane gasoline.

Freestyler, Thats exactly what I wanted to hear, thanks.:)

PaulG, I will look into the price of a piston, but with a hole in the old one and metal melted, isnt there going to be peices of metal all throughout the block now, and possibly the cooling system? A used one would not have this, although I guess I couldnt really know how good a used one is either.


Also How do I know the used one I could get isnt ready to die? Compression check, but what else. If I did get an engine is it worth pulling the head off and putting on a new head gasket while it is out of the vehicle?

Best Regards,

Josh

jrbnc

How did this engine run before Nuclear Meltdown ? :eek:

The engine had low compression in #3 i think around 90 if I remember correctly. So the car shook at idle sometimes, but was fine on the highway. A dog off the start, but pretty good pep up around 65mph. Then this happened.

What do I ask about?
 

I have been calling around today for used engines, what should i ask for about an engine, so far I have been asking:

1. Compression readings / leakdown test?
2. Mileage
3. How car was wrecked
4. any headwork or chain replacement
5. Any warranty
6. of course price with shipping.


What else should I be asking to be sure before I buy? And will it matter if mine is an automatic and the engine is from a manual?


Thanks again,

Josh

How many miles on your engine?

Think about a price check between a used engine and getting the one you have rebuilt if the one that blew has lower milage than the used one. If you have the tools doing a rebuild yourself is well worth it. You should not have any metal in the cooling system. Just the oil pan. The melted metal should come off of the valves with a little effort. If it damaged the head you can have a shop do your valves. A lot of variables to think about: time, skill level, money, amount of damage.

I wish you well.

Sometimes it looks really bad when in fact it really is not. Have faith.
:)

Josh

You are on the right track with your analysis questions. I would be doing the same. If you look to get a used one from someone you should be able to run a compression test even out of the car with a battery.

-find out whether the engine has had a head job .... cylinder head gasket and/or valve guides and seals.

-depending on the damage replacing the damaged parts maybe the way to go.

I a way I have been there and one that - do become a student of the subject as you are doing. There are two direct benefits: You are ensured of making the right decision AND you always learn something in the process that helps later on.

Keep us posted, we are pulling for you.

Haasman

jrbnc

Just another little footnote on this topic.
Regardless if you go for another engine, or repair the one you have, you will either be re-using or transferring your misc. parts.
Because of the meltdown you've described, I would have a very good look to see if there is a problem with the # 3 injector or intake gasket.
I'm saying this, because I suspect you may have had a very lean condition on that cylinder. ;)

jrbnc,

What a great opportunity! Pull your motor and find someone to help you go through the lower end and clean up parts.

Have a machine shop or better yet a race shop give your head a good 3-angle valve job and surface the head. Have them remove any sharp edges off the pistons and combustion chamber and set the piston to head clearance to 0.035".

Get some Total Seal rings for your pistons. And get a race quality bore hone and prep.

Assemble and have a ripping motor that will be dead stone reliable and the cost to do the above is most likely cheaper than buying a used engine.

Be prepared for about 40 extra Hp.

Jeff

Engine Removal
 

Does anyone know where I can find some detailed information and tips on engine removal. I have the haynes manual, but I dont really trust it too much. What accessories need to be removed before removing the engine? And what can just stay put?

In particular what about the a/c will i have to have the system evacuated? I suppose so in order to hook up the compressor right?

Thanks all!!

Josh