I have a rodbender w140 which did indeed bend the rods. The car has 158 on it and always ran great. A young girl drove it for years. The funny sad part is that me driving the 350 around and really seeing what that extra .5 liter could do bent the rods. I did a full throttle run about 10 times and now the rods are bent.


The plan is to replace the motor with the 3.0 603. I know of an available early 603 that has a cracked head. Its been sitting for a bit (lots of leaves) and i found coolant mixed with the oil under the valve cover. I have that 3.5 liter head that i want to use but im wondering if the coolant in the oil has likely destroyed or damaged the lower end? When these heads crack is the issue so sudden and obvious that the car is undrivable? Would any of you take the risk? I can get the motor for under $400

__________________
1981 300SD 512k OM603

Yes a toasted lower end is very possible.

Before shelling out $400 for a potential boat anchor, is there anyway the seller will let you pull the head and the pan?

As far as bending rods in your 140, what makes you think your wot runs did it? As I understand it, these engines can run quite well with bent rods, depending on the severity of the bend, of course. Perhaps they were already underway.

__________________
Chief

1991 350SD

Well the car began drinking tons of oil and running horribly after i met her... The car smokes bad on startup, uses a quart every 50 miles and smokes really badly without load downhill.

Yes i can pull the head first or the lower oil pan.

__________________
1981 300SD 512k OM603

I think it would take awhile of running with a sufficiently bent rod(s) to deform the cylinder such that you are using so much oil, but I'm no expert.

Pull the head and the pan and have a look. If all looks good you are on your way!

__________________
Chief

1991 350SD

I understand it can also be a headgasket leaking oil. From what i have heard compression tests are not very conclusive and the head must be removed to really figuer out whats going on

__________________
1981 300SD 512k OM603

What would i see by pulling the lower pan? Would i have to pull the #1 cylindrs rod cap? Is it even accessible like on the 617?

__________________
1981 300SD 512k OM603

If you first pull the head and the cyls look fine, that's a good sign. I would then pull the pan, and look for any evidence of coolant in the sump. This may be difficult since it is a jy engine. I would pull a main cap and a rod cap or 2 just to look at the journals. Why not find out all you can before buying it?

A head gasket could be the culprit. Have you checked the upper radiator hose for pressurization ?

Bent rods can be readily assesed with the head off. MB has a spec on how high the pistons should rise above the deck of the block. A bent rod would not allow the piston to protrude above the deck sufficiently to meet the spec. In my own case, it was quite obvious without the need for any measurement. I'm doing my own 603 refit to my 91 350SD right now. This thread chronicles my "adventure."

Intro and First Question: Engine Starts Smooth, then Runs Rough

__________________
Chief

1991 350SD

As Chief said but I'd go further. On the 3.0 block I'd visually inspect and Plastigage each main and rod bearing. Look for debris caught in the oil pump pick-up screen. If that's good, pull the head and check the ridge and cross hatch in each cylinder. If the block isn't usable as is, wait for a block out of a running car. There's no economical way to rebuild a 603. Sad to say, Metric Motors is the cheap alternative.

You can gamble with a new head gasket on the 3.5. It might cut down oil consumption and exhaust smoke enough to put a smile on your face for a while.

Sixto
87 300D