Here are all the photos. I'd rather them be on the peachparts server.

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more photos

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Comparison of sideways wiggle is the test once used. It can be measured. comparing it to other valves and guides on the head. Not really all that scientific but a general indicator. A dial indicator should be enough.

No way as accurate as a bore gauge. But if you do not have one laying around and use it ofen enough to trust the feel.

I have a hard time getting the right feel when using machine shop measuring tools. I like a micrometer with the click stop for example. It takes away some amount of judgement call. Since I suspect you are going to have an automotive machine shop do the seats and valves. Why not let them tell you?

Even if you where to drive in a new valve guide it would have to be reamed for the valve stem and the seat machined to match the orientation of it's bore. At one time a machine shops bill was quite reasonable for this. Times have changed but some shops still might have decent rates. Ask your local mechanics who is a good and reasonable shop to use at the same time. Ask at least couple to find out one they recommend.

This of course after finding out if everything else is okay or not. Well Hunter was also right on one of his expectations . There really is a tad of carbon buildup present there.

Two points.
#1. In your picture, that is a broken valve GUIDE, not the valve.
#2. Your cylinder is drenched in engine oil, his is fuel coked from low compression/incomplete combustion.

Army, what caused your valve guide to break? That is very unusual.

petecooke, where are you located? I have a good head from my 83 240D, still in the engine, in CT. If you don't want to fix yours, my head is an option. My engine ran good. Did 0-60 in 17 seconds, documented in videos.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

A piston crown as hammered as your can mushroom/expand (like the top of a chisel) to the point where it will contact the cylinder wall, and then the piston will seize.
Also the piston can cracks due to the damage.
If it was my engine, I would replace that piston.

__________________

76 240 D. Bought in 1998 for $25.
85 300D. Got it for free with a bad engine. ( Sold )
60 Unimog 404. What was left of it, was given to me. Now powerd by 617A.
88 560 SEL. Bought without engine and trans. Now powerd by 617A.
67 250 SE. Cuope. For resto or sale.
64 220SE. For resto.

I'm Maryland. CT would be a cruise. I am going to make some calls today to find a machine shop.

Would you recommend replacing all the valve guides or just focus on the #3 piston, valve and valve guide?

Might as well do all 4 while it's apart. Another option is take my engine. It has 221K on it and ran great before parting out due to rust. IP and Vac pump is gone. Everything else still there. Maryland to CT is 5 to 6 hours.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Yes what a dope! I meant to say guide as in girl scout XXXXX book...

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

I can only guess at what happened to the guide. I assume it was due to some Mercedes "expert" from whom I bought the car adjusting valves with straight spanners. You can read all about it here

http://www.peachparts.com/shopforum/diesel-discussion/276144-om-617-manifold-oil.html

And I did find later on that the "group of three" rocker arms were positioned incorrectly on the head. (Only applicable to the OM617 of course)

OM617 rocker arm problem?

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Do you really want to pull the head again in 50k or less??
Replace all of the valve guides, and be done with it..

Good point. I will order 4 new stems.

On another note, I flipped the head over and the piece fell to the ground. I'm not sure where it came from. Does anyone recognize it? It had oil all over it but I cleaned it up.

-pete

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I brought the head into a machine shop and as soon as the tech looked at how the valve was seated, he said "the valve is bent".

He then took the valve off and put it into a machine that spun the valve around and you could see that the valve shaft was bent.

At least I know what the problem was but I'm not sure what could cause a valve to bend.

I also attempted to scrape the carbon off the piston but what I thought was carbon seems to be metal. It looks like the top of the piston melted a little.
Does the piston have to be replaced?

That piston is probably still structurally sound, but its surface is so compromised that it would probably affect the combustion process. I would vote for replacement also, rather than having to do the job over again when you are left with a noisy/smoky cylinder.

Options, pull the engine :
* Get a good used piston + rebuild the cylinder head + timing chain + head gasket set + at least one injector.
* Get a good used engine to drop in.
* Rebuild the existing engine with all new parts.
* Junk the car.


Note: Cylinder head rebuild should include cleaning, re-surface (if needed), eight valve guides, eight valve seats, valve stem seals + replacing any valves that are beyond spec.