OM617 Wrist pins- Should I do them while I'm in there? If so, how?
 

Well my friend dropped one of the main bearings while working on my dad's 617 so we're going to redo the bearings. I was sorta wanting to do them anyway, they didn't have much of any wear but a sort of while we're in there sort of deal. We're already redoing the rings.

Question is, should we redo the wrist pins? I say yes, but he thinks it's too difficult of a job. Does anyone have insight on that? They're not very expensive.

You need to access the Mercedes Manual for your engine.

On other Diesels you measure the Pins and the bore the pins go into and you get the clearances and compare them to the limits in the specs. There is also the connecting rod bushings.

Unfortunately if you replace connecting rod bearing the small end/Piston Pin end you need to ream or machine it to the proper size. (I used to do this where I worked. The Rod has a specific dimension from the center of the large end bore to the center of the small end bore. You adjust that on the machine. That way when you bore out the small end bushing it has as specified length. Merely running a reamer through does not guarantee the length from the center of the big end to the center of the small end will be correct.)

There is no pictures in the CD Manual on reaming or machining the small rod end bores

The machine was called a Tobin (the maker) Pin Boring Machine.

In the manual I am not seeing separate Piton Pin Bushings/Bearings in the pictures.

I had myachine shop press in and machine them to the pins. It was only $30 to have them all done, but they do have to be matched to the pins.

If you have everything apart, you might as well do it.

Did the bearing get damaged?
If not it can be reused if it isn't worn.

Good luck!!!

Is that Anaheim CA?

Yes, I went to L&B Con Rod in Anaheim. They are not Mercedes specific, but Alfred there had done these OM617s before, albeit not in the last decade before mine.

I'm happy with the work they did.

Thanks I am not far away.

Not a problem. They did new liners, bored them out, decked the block, did a valve and seat grind, polished the crank, pressed in my new valve guides, and did the aforementioned wrist pin bushings for me, along with hot tanking the block and head. I have about 1000 miles on it now and no issues so far.

Just remember that every part of the rebuild that you do not do yourself is a risk. You folks are lucky if you know a good machine shop. You're relying on the services of another person, hoping that it will be done right, and that the equipment is still up to spec as well as the replacement parts. I am not saying they shouldn't be replaced, however the chances of damaging a rather rare piston will be greater the more you mess with it.

If you go as far as wrist pins, you might as well blueprint the Pistons while you were in there to verify that the ring lands, pin bore and skirts are all within spec. If the rods are reconditioned you will have to check side to side play with the thrust area in several different spots around the circumference of the rod journal. New rod bolts are a must unless you have a method of measuring stretch. Our motors were put together blue printed from the factory. The more that is touched inside that motor, greatly increases the chances of a mistake.

When I worked at the Naval Shipyard the Shop that I was in rebuilt the Engines for the Navy; mostly Detroit Diesels and we went on the Ships and rebuilt the Engines on the ship if they were too big to remove.

Across the building was another Diesel Shop that rebuilt the Engines for the Mine Sweepers. Not sure why there was 2 shops but we rebuilt the components for their shop including turbocharger, water pumps and oil pumps and Air Starters.

We did some machining of parts. A great practical education but no equipment at home.

I have done about five mb engines, four diesel. I am pretty sure no work was ever required on the wrist pins. I am sure you can measure them though.