The ridges may be mostly carbon. I doubt you can tell a lot (unless you are a very experienced professional machinist) just by looking at them. I would have the bores measured for wear with the proper tool by a machinist who you trust.

The pistons in my experience can be reused much of the time. They must be measured by a machinist with the specs and the right equipment to see whether they meet specs to re use.

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

The block with the damaged cylinder virtually has no ridges that I can feel by running my finger over that area. The original engine that I tore into yesterday by contrast had a noticeable ridge by feeling for it.
I don't have the money to spend to do a restoration/rebuild on this engine. I just want to get it running for as little as possible. If this were an expensive car and could seeing getting out what put into it if I were to sell it then I would spend the time and money to do a textbook job. I'm hoping to get it going for little more than the cost of new gaskets and seals.
It was running good before what I assume was a prechamber that broke apart and damaged that one cylinder. By examining the cylinder that got damaged, it appears the damage is only in the area where the rings don't reach. I think if I can match up a piston to replace the damaged one, I think it could be OK. I know the standard pistons come in about 3 different dimensions and are matched to the cylinder bores. I have to try to determine which piston size is the one that is damaged. That'll be difficult due to the damage to the top of the piston.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

I am new to this forum. What a great resource!

About a month ago I brought home a non-running 79 300D. My Son will be getting his license in about a year so I figure this will be a good learning experience for both of us.

I got the car to fire up and run from a bottle tank for a couple of 5 minutes intervals before it gave a loud bang and put a connecting rod through the block. - Ouch!

I just stripped down a different 617 engine. This engine had originally been in this same car but seized up when the oil plug fell out. Ouch! My friend put this siezed engine in his garage 6 years ago when this occurred. When I told him my story of woe with the connecting rod through the block he gave me this siezed up engine to tear into and see if the block might be salvaged.

Today I took the "hopefully good" block to the machine shop to be hot tanked and closely inspected, along with the crankshaft and main caps.

From what I have gathered from reading posts on this forum, reading the Factory CD manual and a Haynes manual, I have come up with a general idea on how to proceed that I would like feedback on.

Tentative gameplan:

After getting the green light on condition of the block and crankshaft, I will resleeve all 5 cylinders, using a press that a freind is loaning me, and borrowing, buying or having fabricated the sleeve removal / insertion mandrel, the drawing for which I obtained through this forum. I will then take the block, with new sleeves installed, back to the machine shop so they can mill or grind the protruding sleeves to the level of the block deck, then hone to 25 degree cross-hatch. I am planning to take my new collection of pistons to the machine shop at the same time so they can select the best 5 and hone to fit for each cylinder.

I agree with the logic of using new pistons but I just don't want to run the rebuild costs up if I can use the pistons I have.


Also:
I need a removal/installation mandel - I have the drawing.
I need a tool for pressing the two steel balls into the oil galleries. I knocked the steel balls out of the block before taking it in to be hot tanked. Do I order the steel balls from Mercedes?

It occurred to me that you need balls of steel to make your way through a rebuild like this with no prior engine rebuilding experience. My motivation is largely the learning experience and it certainly is interesting so far.

Any feedback is welcomed.

Regards

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gburnett

1979 300D 250,000 Miles

for new members

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
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Dynamometer.
Heat exchanger durability.
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1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

Also a quick stop here Oil on da brain would be a good idea after this thread.

__________________
DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012