There are MANY crankshafts that are cast iron. I don't know if these are or not. I do know that the turbo cranks are nitrided and the non turbo's are not.

Have a great day,

If there IS a Woodruff key, it is not at the juncture where the crankshaft meets the damper. There are two ROUND pins in this location. At least there are on the 616/617 engines that I'VE had apart.

You can call me a liar if you want. I only know what I've seen when I've taken them apart.

Have a great day,

airfoill,

If you get another harmonic balancer (HB), how are you going to balance it to the crankshaft? The HB is just what the name implies: a balancer that is balanced in the factory by drilling some of the mass away to take any vibration out of the rotating crankshaft.

Maybe you could take the new HB to an automotive machine shop and have it drilled approximately the same as the old one.

P E H

Larry,

You can't nitride or harden cast iron. I really don't believe a crankshaft would be made out of cast iron. Cast iron is a very weak material in a shock condition, such as a the firing of a charge in the cylinder, especially in a Diesel. You can pound on a piece of steel all day and it will only deform but cast iron will crack.

I would have to see a cast iron crankshaft to believe it.

P E H

Peter

I was under the impression that after the early '70"s all the parts were balanced separately and all you need to do is line up the marks, flywheel to crank and the H/B only goes on one way. (for TDC of #1) So a differant one should be fine.

Steve

P.E.,

For all I know there has NEVER been an MB crankshaft made of cast iron, but MOST American car crankshafts have been made of cast iron.

As an example, many of the small block Chevy crankshafts are cast iron. The 283's were steel until 67, then all but the highest performance or heavy truck applications were cast iron.

You can go to the nearest wrecking yard and you will have no trouble "seeing" a cast iron crankshaft. They are easily recognized by looking at the parting line. A cast piece will have a very thin parting line, where a forged shaft will have a parting line that is 1/2" or so wide.

Have a great day,

Maybe you are thinking of mallable iron which is quite different than cast iron.

P E H

the picture from the book..

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the legend for the picture...

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The woodruff key keeps the crank sprocket in position. Item 23 "fitted pins" are what keep the HB in position/lined up. Personally, I have never had much trouble putting an HB back on the crank correctly. I very slightly offset the pins and holes and as I tighten the crank bolt to pull the HB on the HB "turns" just enough to eliminate the offset and they line right up.

__________________
Jim

Yes, if you will examine the diagram/parts list you will see that the woodruff key is between the crankshaft and the crankshaft sprocket. This thread, however, discusses what many of us here have been calling the harmonic balancer or in more precise terms in the diagram, the crankshaft disc.

Jim, I have been lucky enough to get one of these in position in one or two tries by doing as I described earlier and having the holes slightly counterclockwise before starting the bolt. The bolt then turns it into place. Other times it has taken several times to get it properly aligned. I consider proper alignment to be where I can get the dowels in place with very light tapping with a small hammer.

P.E. The term commonly used for the iron crankshaft is "cast." I'm no metallurgist, so technically maybe it is malleable iron, but it is cast into place. The more modern "cast" cranks are nodular iron. These nodules, of what material I don't know, are mixed throughout the material and add strength.

Maybe they technically are NOT cast iron, but that's the terminology that I've seen used for some 35 years or so. My point is that there are indeed crankshafts made from material other than steel.

Have a great day,

Larry,

Yes, I think what we need here is a metalurgist. Steel is an alloy of iron, about 97% to 98% iron with the other 2% to 3% being carbon and other alloying metals. Cast iron is iron with about 5% carbon and practically no other alloy metals.

Mallable and nodular iron may be somewhere between steel and cast iron.

I'm still in the process of getting the right size 18MM tap to chase the crankshaft threads in the snout at the front of the crankshaft. Does anybody know the correct pitch for the 18MM tap?

Thanks

Herb
'82 240D
'87 300SDL
'92 300D 2.5 Turbo

Airfoill,

If you find a place that has M18 taps, take the crankshaft bolt along and match the threads. When the threads of the tap mate with the threads of the bolt, you have the right one.

BTY: Correct terminology: Chase threads means to cut threads on a lathe. You will be retapping the threads.

P E H

Herb, I assume you saw in the legend on the picture the info on the threads....