m104 con rods in a m111 - PeachParts Mercedes-Benz Forum

wis · #1 05-15-2010, 10:26 PM

anyone know offhand if the rods are the same ?

MAG58 · #2 05-15-2010, 11:38 PM

Which M111?

FYI, M103.98, M104.98, and M104.99 all use the 145mm (48x24) M102.98 rods and are stamped as such on the beam of the rod with a 102 part number. Since none of the 111's share a bore x stroke dimension of a 104 I would say no, but I could not tell you for sure. The 2.8L M104 (.98) does use it's own proprietary rod at 148mm.

Best way to check is see what the part number on your rods says, First 3 numbers will tell you if it was carried over from an older design.

400Eric · #3 05-16-2010, 03:17 AM

Bob, could you please double check that 148mm number? The info I saw said 149mm which is, coincidentally, is the same length as the 3.0 OM603.96x diesel and the second gen. M119s (the "short deck" ones). Also, for reference, the 145mm length is the same length as what was used in the later "rod bender" 3.5 OM603.97x.
Regards, Eric

wis · #4 05-16-2010, 12:32 PM

its a 111.974, i have a 2.8 and 3.2 104 for parts and i was hoping the rods might work, the wife turned her c class into a submarine last nigh.

TurboECab · #5 05-16-2010, 05:28 PM

M111 rods are the same.. I have 3 junk motors can get you a part number if you need it.

MAG58 · #6 05-16-2010, 07:43 PM

Quote:

Originally Posted by 400Eric

Bob, could you please double check that 148mm number? The info I saw said 149mm which is, coincidentally, the same length as the 3.0 OM603.96x diesel and the second gen. M119s (the "short deck" ones). Also, for reference, the 145mm length is the same length as what was used in the later "rod bender" 3.5 OM603.97x.
Regards, Eric

Keeping me honest. You're correct they were/are 149mm though I'm quite sure they're different from the M119's as the V8's have offset journals IIRC (the left and right bank of rods are mirror images of one another) and the bearing shells do not sit centered in the rods as the I6 rods do. The OM rods may be the same length but I do believe that the small end of the rod is larger than the 24mm sparkplug rods. That I cannot confirm though.

wis · #7 05-16-2010, 10:39 PM

part number would be helpful. any of those junk motors got a few good rods you would be willing to part with?

TurboECab · #8 05-17-2010, 12:31 AM

Quote:

Originally Posted by wis

part number would be helpful. any of those junk motors got a few good rods you would be willing to part with?

Will check tomorrow and post number. I believe I have at least 6 good ones out of the 12.

400Eric · #9 05-17-2010, 01:03 AM

Quote:

Originally Posted by MAG58

Keeping me honest. You're correct they were/are 149mm though I'm quite sure they're different from the M119's as the V8's have offset journals IIRC (the left and right bank of rods are mirror images of one another) and the bearing shells do not sit centered in the rods as the I6 rods do. The OM rods may be the same length but I do believe that the small end of the rod is larger than the 24mm sparkplug rods. That I cannot confirm though.

Oh, I wasn't claiming the rods were the same, just that the lengths were the same. Probably a tooling thing.

Although I would add that stranger things have happened. An example is AMC. Some 232 I6s and all 258 I6s use the exact same rod as the 290-360 V-8s. It's just machined differently for V-8 use. (More metal is shaved off of one side on the V-8 version.)
Regards, Eric