This measuring technique would indicate whether the rod bends around an axis that is transverse to the axis of the engine. This mode of bending seems rather strange to me.

The typical bend of a connecting rod in a gasser is around the axis of the engine. When the rod is at an angle to the piston (nearly all the time), the loading on the rod is not symmetrical and it's failure mode will cause it to compress and twist relative to the engine axis.

Anyone have information as to whether this is true in the 603.97?

http://www.remanufactured.com/Mercedes_Engines.htm

I don't know how good the rebuild is on these engines
from this place but they might be cheaper.
Unfortunately there is no 350 listed only the 300sd, but
they do have them, atleast that's what they say.
A 300sd long block is $4100(includes shipping) after the
core deposit is returned.
A short block is $300 less.

Louis.

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Not always the smartest but certainly not dumb?

I hope mine show up like that. I KNOW I'd just put in a head gasket and have the valves done to include having the head checked for leakage and would forget about a bent rod altogether.

BenzDiesel

Anybody who is so stupid that they cannot post an advertisement for an engine and get the correct number of cylinders for that engine is a person that should be avoided. This clown appears to be of the e-bay seller ilk.

I found the same zero in front and less than a mm in the back that you found. I also think the egr deposited alot of carbon build up in #1 cylinder, which contributed to the valves not fully seating in the piston grooves because of the carbon build up, which didn't allow the valves to function properly as designed to, which in my opinion could have contributed to my oil consumption (I hope so). I found minimal cylinder wear at the ridges and a couple almost feel completely ridgeless. Have you seen any actual pictures of a bent rod? Anyway, I'm encouraged and will check the head out further tomorrow and see what I find there. Also, it looks like the backside of the gasket was breeched at #1 cylinder and possibly at #6, as well. Anyway, I'm on it.

BenzDiesel

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You checked protrusion with the gasket off, right?

Why is there oil all over the #6 piston?

Your pistons are and head are a lot cleaner than mine. There's deposits all over the place in my engine. Not as much oil, though.

Sixto
93 300SD

That is why it would have been great to see an actual bent rod or a bent rod condition, as it relates to the obvious damage done to the cylinders caused by a bent rod. And yes, the protrusion was checked with the gasket off. Also, in THEORY, a piston is just a big plug that pumps and compresses, so I'm still having difficulty seeing why a slight tilt, possibly indicating a bent rod, can cause so much destructiveness in terms of high oil consumption, when the piston's job is to just plug the hole so that compression can take place.

BenzDiesel

Remember that the cylinder ovaling will be at the BOTTOM of the bore, not the top. So I'm not at all surprised that there is minimal difference in ridge at the top of the bore. Also, the bent rod would likely require precision tools to measure the bend... it's not like it's going to come out of the block with a big ol' curve in it. I'm more interested in seeing an old, stock, bent rod next to the new, improved, updated rod; to see if there's a visible difference between them. I vaguely recall someone posting photos a few years back but if so, I didn't save them (d'oh).

Would you know the axis of the bend in the 603.97 rods? Does the rod bend around an axis that is parallel to the engine axis or about an axis that is transverse to the engine axis?

If it's transverse, the visible difference is obvious. It also explains the ovalizing of the cylinder on the front and rear cylinder walls.

If it's longitudinal, you might not see it. The ovalizing in this scenario escapes me.

In my case it seems the rods are bent in the piston's pitch axis - the front edge of the piston is lower than the rear edge. I'm not sure how that manifests as cylinder wear since there isn't much fore-aft loading as a result of crank rotation.

Sixto
93 300SD

Nope, I'm not sure of the axis. To date, I don't really know anyone who has seriously investigated the root cause of the problem, I think y'all are pioneers in this area. I do think the speculation about carbon chunks or oil ingestion causing it are a little unlikely though. The 2.5T is also known for blowing head gaskets into the timing cavity and sucking oil into the #1 cylinder but I've never, ever heard of a 602 bending a rod. I think MB just screwed up with the original 3.5L rods (no idea why) and for reasons that still escape me, it tends to appear on #1 first.

I wonder if any of the Finns have played with a 3.5L SuperTurbo...?

Does MB have updated rods that take care of the bending problem? Then maybe you can get away with one rod, one piston and one liner, but I guess I would think about replacing all the rods while I had the engine apart. Then tht leads into new rod bearings and a rering too. I guess then you have to look at costs compared to a rebuilt engine with warranty.

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Doug

1987 300TD x 3
2005 E320CDI

A good used 606t from pgauto.com is $4000. That sets the limit how much time and money will go into getting the SD back on the road

Sixto
93 300SD

Does a 606 bolt up to your tranny? What about engine management? Is that all part of the engine price?

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Doug

1987 300TD x 3
2005 E320CDI

Now you are talking! The 606 is the motor that belongs in the W140!

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1969 280SE
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