I pulled a 617 engine today and these are a couple pics that I took. WARNING - if your tensioner/slide rail looks like this your valve cover will look like what is shown. As far as I am concerned this engine was on borrowed time.

DISREGARD THE DATE ON THE PIC - I am too lazy to reset the camera after changing batteries.

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Jim

Dang....that thig certainly has been slapping the cover.

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Proud owner of ....
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

engatwork, miles on the engine?

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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around a quarter of a million

I got the head off yesterday and the cross hatching is still evident so I will not be doing anything to the bottom end except replacing the front/rear seals. I suspect the bearings are going to be in good condition.

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Jim

Jim, I am unable to clearly see the issue in the first picture.

Can you elaborate?

I'm in the middle of pulling the head on the 617 so this is of personal interest.

Brian - look closely at where the tensioner pushes against the slide rail. Major wear which resulted in the tensioner being all the way extended and the chain is still not quite tight enough. I pulled the engine/tranny on the car and will be replacing the front/rear main while changing out all the chain slides, oil filter hsg gasket and fuel inj pump gasket. I'll post pics here in a little while of one of the other slides that was badly worn. More than likely I will have the machine shop go through the cylinder head while it is off.

This is a fella mbshop members car - '85 300SD.

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Jim

Got the block torn down (except for pull the crank, pistons, etc.). I am not plannning on pulling the pistons, just the crank to allow me to replace the rear main. Here is a pic of the lower slide rail that is worn out. Also, note all the silicone sealant that was trapped in the oil pump screen. Someone had replaced the front main seal at one time and used silicone sealant on it that had broken loose. Thank goodness for that screen.

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Jim

Do I wish I could work as fast as you do.

I spent most of the day trying to figure out a way to break the nut that holds the bracket underneath the turbo. After about four hours, I gave up and removed the lower nut that holds the bracket to the block. But, if you do this, you can't lift the head with the manifolds attached. The bracket must move toward the passenger side of the vehicle and off the stud. So, you must remove the manifolds to do it.

So, I did. Once I got the oil feed line out of the way by removing the bracket from the back of the head, both manifolds and turbo came out with relative ease.

All head bolts are loose and the rocker groups are out. Just need the engine hoist and I should have it off in about an hour.

Now, I'm staring at a starter that can be changed in less than 30 minutes.
Hmmmmmmmmm............very tempting. Think I should keep a 20 year old starter when it's 10X easier to change it now???

I pulled the slide rail and it shows no wear at all.

I'll check the tensioning rail for the grooves that you have shown above.

Can the tensioning rail be checked satisfactorily with the rail remaining in the block? Is the visibility acceptable?

Do you replace the chain tensioner as a matter of principle? A dealer item?

Any other things I should do while the head goes out to the shop?

I've definitely got to do oil cooler lines and the gasket between the oil filter housing and the block.

Regading the starter. Since you aren't in a real big hurry to put it all back together, why not take the starter to an auto electric shop and have them either check it over or rebuild it. The one on my SDL cost me $113. They rebuilt it as well as polished and painted it so it looks brand new. Beats buying a rebuilt from Bosch when you pay the price of the core just in sending it back!

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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Having a lift makes all the difference in the world. The way I got the upper fastener off that you were unable to break loose was to heat it up and then I was able to remove it.

The slide rail that I show pics of with the most wear is one of the ones in the lower part of the block. I do not remember if it is the inner or outer one. The last two 617 engines I took apart this rail was by far the most worn. In addition, you will find the oil pump tensioner rail worn to the point of needing replacement while you are in there. I would definitely replace it if I were you.

Brian - are you pulling the whole engine? If no, how are you keeping track of TDC on the timing chain? Be extremely careful during reassembly to NOT lose track of TDC on the crank and cam. I have made that mistake before. How many miles are on the engine you are working on?

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Jim

I'd do the starter and alt if they are original. Resealing the turbo is probably not a bad idea as well. The starter in my SDL seems fine but this winter when I lay it up I will pull it and let a shop rebuild it. 17 years old and I do plan on taking this car on some long trips. Last thing I want is for a rare starter to die in FL or Canada on a Sunday.

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Well, I heated it with Mapp gas but, not well enough, obviously. I didn't want to bother to drag the oxy/acet rig out of the basement.

As far as I understand it, that is the "tensionsing rail". The "slide rail" is the small plastic piece in the head. Please correct me if I am mistaken.
Now, where exactly is the oil pump tensioner rail and how do I get at that from the top?

I've painted a white mark on the chain and onto the sprocket. So, I know the position of the chain with respect to the cam. I'll suspend the sprocket with bungee cords while I pull the head. Then I'll shove a welding rod through the chain on top of the block to keep the chain on the lower sprockets. Sound OK? The engine is currently at TDC on the #1 cylinder prior to the power stroke.

The SD has 180K on the clock.

David, my thoughts are exactly the opposite. The local rebuilders will put in just enough to make the damn thing work again. Hell, if I bring them this one, they probably will give it right back to me without even working on it.

How long is it going to last? Five years if you are lucky. The existing one may last another five years and it costs me nothing to leave it in there.

With a Bosch rebuild, you pay dearly, but, I'll bet you don't need to do a starter for another 20 years.

Drop it off and ask them to rebuild it. They won't complain. I read somewhere on here that the average life for one of these starters was ~7 years.

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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Are you speaking of the average life of a Bosch rebuild or the average life of a Joe Blowe rebuild? I've got to believe that they are significantly different.