PeachParts Mercedes-Benz Forum - Where'd my valve guide go? Help pls.

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- - Where'd my valve guide go? Help pls. (http://www.peachparts.com/shopforum/diesel-discussion/279247-whered-my-valve-guide-go-help-pls.html)

I had the valve guide on my Harley get pushed through the head to the other side once. It wasn't pretty. Maybe this occurred gradually. I don't recall how much room there is on the other side before it hits something.

Quote:

Originally Posted by soulbandaid (Post 2487264)

Wouldn't this cause the valve not to close because of the length of the Mercedes valve guides?

See the pic in post #6 there is actually room for it to drop down some.

I think I have figured out a way to change the Valve Guide without removing the Cylinder Head.

But, please remember I am not there to see it and I have not had a Mercedes Cylinder Head off or changed any Valve Guides on a Mercedes.

Remove from the Head what ever parts are needed so that you can get at and remove the Valve springs just as it is in picture in the original post.

Rotate the Engine by hand and let the Valve drop down enough so that you can use a Tap to thread the inside of the Valve Stem Guide.
Use a Slide Hammer and pull out the Valve Stem Guide.

Do what ever is needed to clean out the Valve Stem Guide hole.

Rotate the Engine by hand to TDC so that the Valve is all the way up.

You will need some sort of Tube that will allow you to drive in the new Valve Stem Guild and not mess with the Valve.

Slide the new Valve Stem Guide over the Valve Stem and drive it in.

Put on the new seal and assemble the Head.

Quote:

Originally Posted by Diesel911 (Post 2487589)

Isn't that more or less what i said in the fist post minus the removing the bad one part?
I think you would probably lose the valve when you tried to pull the sleeve. There isn't really much clearance between the cam and the valve guide hole. You'd have to get teh vavle way down and even then you'd probably need to pull the cam in order to apply any significant pressure to the new guide. But I've heard people say that one can fish out a valve with a magnet (sounds like almost as much fun as pulling the head :-P)
I also get the feeling that that guide is not a Mercedes one. It's machined flat on top and the valve closes all the way (the car runs well except the oil smoke on start). The mercedes ones are slightly beveled and so long that the valve wouldn't close with it shoved way down in there. I suspect its a machined bronze or brass ring that was put in there with some force (do they do this on other cars?). I wish someone could give me an answer that sat right with me. But I'm the first to admit that I'm an amateur and probably don't know what I'm talking about.

Anyhow doing that and risking making an engine that works with its head onl into one that doesn't work without pulling the head to fix it right (or replace it!:eek:)doesn't really seem worth it when the only issue i have is oil smoke on start and moderate oil consumption in a car I paid 1000 for.

Thanks for all the help and advice.

if you are really upset by the smoke [which you assume is oil] , you could modify a valve stem seal to lay under the 'bearing' or 'rotocap' that sits under the valve spring.

the only thing you can do is wipe the oil off the stem before it reaches the guide.

Another thought is a large rubber washer , maybe viton. Regular black rubber will not last long under those conditions.

Quote:

Originally Posted by soulbandaid (Post 2487646)

I figured that ounce the Old Valve Guide is out there would be plenty of room to "find the Valve"; and a Magnet would work.
I also believey you would need to remove the Camshaft remove and install the Vlave Guide.

This is going to be hard to describe.

You take a shortened piece of a Valve Guide; the part with the lip that holds the Valve Stem Seal on; you would have to figure the length.

you Braze that piece of Valve Guide to the thin washer (the washer needs to be like sheetmetal thin so the Valve Springs sitting on top of the washer do not become coil bound) about the outside diameter of the hole that the Valve Springs goes in.

When you install it you put a coating of Silicone Sealant on the Bottom of the washer and slide it over the Valve Stem. Followed by the Valve Stem Seal.

The Valve Spring will sit on the top of the Washer pushing it down and the Silicone will prevent Oil from getting under the Washer. Since the section of Valve Guide is Brazed to the Washer it will not leak there.

The Valve Stem Seal should seal the Valve Stem itself.

The main rub is that the new Brazed on section of Valve Guide is going to have a tigher ID than the old piece of Valve Guide that is still in the Head; so there would be some side ways force exerted on it when the Valve goes up and down.
It would work best if the hole in the Brazed on section of Valve guide was enlarged so it would not touch the Valve Stem so no sideways force could break it off at the Brazed joint.

Might be easier to pull the Pre-Chamber, bang the valve-guide out into cylinder, and fish it out with a Magnet on a stick!

--All depends on whether the Valve will drop outta the guide with the Piston at BDC--If it wont, then this idea wont work....

Driving in the new guide after the old is out is easy, and getting valve back up isnt hard with long-nose through manifold tract in head after you have the manifolds off....

Problem may be that with the New Guide fitted, the Valve wont seal properly without re-lapping/facing it in, as it may not be in Exactly the Same position as the Old, Worn guide,--With the small side-force on the valve-stem imparted by the follower, the valve seat after a few hundred K miles wears slightly eccentric.....:rolleyes:

I agree with Alastair, except that pulling the prechamber will not help you remove the valve guide, really.

and that guides usually need a good reaming before the valve slides easily.

you cannot (properly) install a new valve guide without removing the head.

work with what you have.

Quote:

Originally Posted by jt20 (Post 2487649)

You know I had the same exact thought after I put the valve cover back on. The oil smoke bugs me, mostly because i want to sell the car and it looks tacky when a cloud of smoke comes out as you start it:o. Oh well, after spending three days with it apart (i work slow cause its hot here) and stripping the oil filter lid stud )DOH(. I'm not all that motivated to take the vavle cover/valve spring off again.

Quote:

Originally Posted by soulbandaid (Post 2488048)

honestly,

it probably is not worth your time. The whole point of having the valve stem rise above the rotocap is because that area fills with oil.

Having a valve guide cut off flush with that surface severely limits your options to making an effective seal... ever... without removing the head.

actually, post #22 by D911 is the only fix worth trying.

it is rife with potential failures and you will need some very precise work done... but it is the quickest / least invasive solution.

Link to the same discovery

Check this posting out...specifically post #53 on page 4. I found the exact same thing. White smoke and all. The seat was wallowed out pretty good and needed a full valve job. I think we drove this car for a long time like this, maybe even since we got it until the headgasket let oil into the coolant. The car ran good, up to that point.
http://www.peachparts.com/shopforum/diesel-discussion/312485-85-300td-blown-headgasket-4.html

And here I was thinking I was unique....seems the broken guide is not uncommon. I sure wish Roy lived near North Carolina though, even having done it once now I believe I'd still rather hire a pro to do that job.... Although I'm planning on a full 617 rebuild just because I'm crazy....and Stretch needs competition from this side of the pond.