I think even the M103 cranks are forged and I think Maggie is saying that the 3.0 M103 and 3.0 M104 are in fact the same exact crank.

Mag, I think you missed what I was saying. It seems to me that if the 3.2 crank is in fact a recycled 3.0 OM603 crank like we think it is it should be much closer in weight to the 3.5 OM603 crank's weight rather than being only a pound heavier than the 3.0 M103/M104 crank. A one pound difference between a gas crank and a diesel crank? Did you possibly miss-post the 3.2 crank's weight? Also, it looks like both those cranks were forged with those lightening scallops. They don't look like they were machined in later. In other words, the 3.2 crank doesn't look like a "lightened" diesel crank, it looks like that 3.0 gas crank. I understand that there is a "OM603" mark on that 3.2 crank but I just can't imagine why it would be so much lighter than the 3.5 crank.
Regards, Eric

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89 300E "Benzer1" 15.924 Uncorrected
93 400E "Benzer3" 14.200 U.C.
95 E420 "Benzer4"
92 300E "Benzer5" 16.299 U.C. Future turbo CNG
87 300D "Benzer7"
87 300D "Benzer8"
87 300D "Benzer9"
87 300D/70 AMC Javelin "Sidewinder-Benzer"
87 300TD "Benzer11"
06 E320 CDI "Benzer12"
05 E320 CDI "Benzer12A"
71 AMC Javelin AMX 401 "Sidewinder"
74 AMC Hornet 401 "C.K.10" 13.63 U.C.
74 Bricklin SV1 "Presto" AMC 360 pwrd.

thanks Eric,i feel much happier knowing i have a forged crank as I imagine that amg just used either the 104 gas crank (forged)or an equivalent diesel one (forged) when they converted the 103 to 3.2, because they defiantly would not have made a special one off crank for a 103 with such a small production run, bet there is less than 100 amg built 3.2 103 engines in the whole world, i bet they only went in the 190e 3.2 amg, 2 or three 124's and i believe 1 300se...

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ce 320 amg
widebody
tiwn turbo
Mutty 'der nail'
soon to be a six speed nail


"some mods improve your car and make it into something it never was, other mods, however, although essentially the same, are not, and make that car a ricer"

if your car isnt shiny, you dont know what you are talking about, remember; paint shine = knowledge. In order to be taken seriously, you should spend all your money on paint, (and get a dyno reading).
Dont forget to polish it often

Eric, I'm pretty sure they all came from the foundry rough forged as OM603 cranks (the 3.2 gasser cranks). You can see where a crap ton of material was cut out of the counterweights. I would venture to guess that the 3.5 crank easily has twice as much material in each counterweight. The scallops in the middle of the throws though, you've got me on that one. I just looked at an old pic of my diesel crank (below) and it's definitely not scalloped. There is of course the possibility that for the benzin-cranks they just added another forging die that happened to be scalloped and it came after the initial forging process which had the 603 number forged into counterweight 1.




I will say this though, the fact that they're forged means they'll be a softer material than a cast crank. If you'll notice the heat marks on the throws it means they're induction hardened. If you ever get a crank turned, make sure the machinist knows what he's doing. It isn't a chevy crank. The FSM gives very detailed instructions as to how much can be turned before the crank must be re-hardened and exactly to what rockwell hardness it must be hardened to...

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1993 190E 2.6 Sportline

I have been reading this wondering if you all know that the m103 3.0l crank and rods are the same exact parts for the m104. The rods are all m102 part numbers and the crank is the same exact stroke. The displacement difference is in the bore. The 3.6l is bore and stroke. If you put a 3.6 crank in the 3.2 you end up with a 3.4l. Or a 3.0l would end up with 3.2l. The 2.8l m104 has the exact same bore as the 3.2l but a different stroke. Many parts change as production goes on. If you get new rods for any of the engines they will be slightly different than the earlier ones. I have three different sets of rods and none of them are exactly the same. In fact I was just comparing the m102 2.5 rods to mine that a buddy has and they are the same as the 2.8l m104. The bearings are all the same part number, etc.

Fully aware. Actually mentioned quite a few times in this and the other M104 thread.

FWIW, the 2.6, 3.0, and 3.0-24 all have the same cranks...

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1993 190E 2.6 Sportline

I accidently found an old pic from my new 2.8 block. casting looks better than in the old 300 m24v block.

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500whp.net

so does the 3.2 have a different crank?

they are the 'same' as in they have the same dimensions, and the 3.2 has the same dimentions, but are they the exact same item, or different forgings, of different (stronger) material, thats what i was getting at.

it seems from ^ that the amg 3.2 could even have been done with substituting a 3.6 crank into a 103 block, and no rebore, opening the poss that my engine may also have that crank in it?

__________________
ce 320 amg
widebody
tiwn turbo
Mutty 'der nail'
soon to be a six speed nail


"some mods improve your car and make it into something it never was, other mods, however, although essentially the same, are not, and make that car a ricer"

if your car isnt shiny, you dont know what you are talking about, remember; paint shine = knowledge. In order to be taken seriously, you should spend all your money on paint, (and get a dyno reading).
Dont forget to polish it often

They're the same. the 2.6, the 3.0, and the 3.0-24v m104 all have the same cranks. Only difference between M103 and CIS M104 is that the M104's have a dual row timing chain. Pretty much it.

The 3.2L is different because it has a different stroke. as opposed to 80.25mm it's 84mm. The 3.2 has the same bore as the 2.8L, which has an even shorter stroke (2.8 is the only engine the 2.8 crank came in, iirc it's ~73mm?).

The 3.6 is a HUGE stroke (92.4mm) over any of the other motors with a 91mm bore. lest you have custom pistons and/or rods, it's not going into any of the blocks with their factory pistons/rods.

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1993 190E 2.6 Sportline

No the 3.2l has the same stroke as the 3.0l. This is what I was saying. The crank and rods are the same. I put my old cis 3.0l m104 crank in my 2.8l out of curiosity a few years ago. Found the 2.8 had the same piston pin location so the height was correct. I started looking into the compatibility of parts in the epc after that. Found that the cranks all update to the same part and the rods. The 2.8l is different only because it is stroked different. The pistons are special only because the compressions is higher in the 2.8l than the 3.2l m104.

Please then, give me stroke and bore of each engine... And rod lengths too while you're feeling frisky...

I've got the 3.2L and the 3.0L (as well as a 2.6) cranks sitting in my garage and I promise you they're not the same...

I'll even spot you a few tips: lest it's CIS in the USofA it's a 3.2 or 2.8. 3.0's are rare and don't look anything like 3.2's.

and the 2.8L has a 149mm rod while the 3.0 and 3.2 are sitting pretty at 145.

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1993 190E 2.6 Sportline

fight, fight, fight, fight,
fight, fight, fight, fight.

__________________
ce 320 amg
widebody
tiwn turbo
Mutty 'der nail'
soon to be a six speed nail


"some mods improve your car and make it into something it never was, other mods, however, although essentially the same, are not, and make that car a ricer"

if your car isnt shiny, you dont know what you are talking about, remember; paint shine = knowledge. In order to be taken seriously, you should spend all your money on paint, (and get a dyno reading).
Dont forget to polish it often

I am just putting out the info that I have found in my own research. This data is from WIS at work and the epc. I believe it from what I have found with my own engines.
The 104.98 motor has a bore of 88.5mm with a rod center measurement from the bearing bores of 144.995-145.005. The 104.94/99 have a bore of 89.9mm and the 104.94/2.8l motor/ has a rod length of 148.995-149.005. THe 104.98/99 rod length is the same. 104.99- motors are 3.2l. I have a 104.992 currently that I am running. I took out my original 104.980 years ago but still have it. In the epc both the 103.983 and the 104992 rods update to the same part number 1020302620.
I have swapped rods and crank between the 104.980, 104.94-2.8l, and my 104.992 to see the difference. All parts go between except of course the pistons in the .980 motor are to small. I will get the stroke for each motor when I am at work today and the cranshaft part numbers. I had this data printed out for my own use at home.

I'll agree with you that they all use the M102 2.3 rods (all m103's and the 3.0/3.2 M104's, with the 2.8 using a 149mm specific rod and the amg motor using M111 rods) but you said the 3.2 and the 3.0 use the same crank. That's just not true.

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1993 190E 2.6 Sportline

I agree, the 3.0/3.2/2.8 can't have the same crankshaft since they all have different strokes 80.25/84.00/73.50 . The m103 and m104 980 may use the same crankshaft since both have 80.25mm stroke .

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190E 3.0-24v (M104 980) turbo @ 0.8 bar
1/4 mile: 2.483 / 13.540 / 175.17 km/h (street tires)

Alright, I was wrong. I looked up everything today and according to the epc and wis the cranks are different. The stroke is different at 84mm for the 3.2 and 80.2mm for the 3.0l as you guys stated. The 3.2l crank supersedes to a 606-031-01-01 and the 3.0l crank is 103 030 08 01. I even did the math on the stroke vs cc and came up with around 30cc per mm of stroke.
The thing I do not understand though is that I have swapped these parts around and found that it just does not add up that there is 4mm of stroke difference. I just dropped a piston and rod assembly from my .980 engine in my 3.2l block and it is proud by a little more than 1mm above the deck. The stock 3.2l piston is proud by around .5mm give or take on both. If the cranks are 4mm different then the .980 piston and rod should be 4mm above the deck. The difference in the deck height can be found on the .980 piston pin being around .5-.7mm lower in the piston than the 3.2l piston. This also makes sense from when I had the .980 3.0l crank and rods on my .94- 2.8l pistons all assembled and the deck height looked good. It should have been recessed by 4mm but it was not. I am thinking that either Mercedes lied about the displacement of the .980 engine. It could be around 3.1liters with the smaller bore. I will try and get some measurements with a dial gauge on the stroke when I get a chance but I just do not see it when swapping the parts.
I did find that the 3.6l engine though is the exact same stroke as the 3.5l diesel,99.4mm, and the 3.5l diesel is also a 89.9mm bore as the 3.2lm104. So just the crank gets you 3.5l. The .1liter difference is the small bore change of around 1mm.