The 87 300D refused to start one night, traced to the starter. Its reduction gear system was all chewed up. Got a used one at a local recycler and had it installed at a local shop. Car started normally afterwards. End of story except...

Got to looking at the old starter and it seemed a bit different from the used one I got. A closer look confirmed they were indeed different. Looking at pix on the net, it seems I installed an SR 67x (617 engine) starter on my 603 300D!

It spins the motor just fine, no weird noises or anything so far. But am I risking damaging anything by starting my 603 engine with a 617 starter?

Oh, and does the Bosch SR 67x starter have a reduction drive like the SR 47x?

at the gear before installing to see that they both have the same number of teeth? if they have the same number and are the same diameter, i dont see how it can be a problem. there must be some difference or they wouldnt have different part numbers, but if it works, i would say the motor doesn't know what is turning it it just starts when turned.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

No, wasn't able to count teeth, at first glance they seemed pretty similar! lack of any grinding on start-up seems to bear this out? Will check though.

How about the distance of the ring gear to the bendix gear? Anyone know if Mercedes changed it from 617 to 603? Might leave the starter on if it won't wreck anything...if it all lines up properly, you're right, the motor probably doesn't care what spins it.

You certainly are taking quite a risk with a starter from a different engine. The starter needs a gear that matches the pitch of the engine for which it turns. There is no assurance that this is the situation between the two engines. Furthermore, there is a precise distance that the pinion gear on the starter is set from the ring gear on the engine. Again, there is no assurance that this dimension is identical between the two engines.

The fact that the reduction gear system was all chewed up on your starter is ample evidence that the starter is trying to tell you something.

Are you listening?

Hopefully, you did not do too much damage to the ring gear in this misadventure.

I'm pulling the starter later to check the teeth count and shape against the old starter. I think they'll be pretty much identical. I'm more concerned with how the starter positions itself in relation to the flywheel, not sure if the mounting holes on the starter "ears" and the distances in relation to the bendix gear are the same on a 617 vs a 603.

Reduction drive finally gave out after 18 years...though I suspect the death blow was a little misadventure I had last year trying to start her in low temps with a few dead glow plugs...cranked her like crazy, starter started smoking. Starter hasnt been the same since (slower cranking, sometimes wont crank at all), and at the autopsy the plastic gears inside were fractured, and one of the smaller gears shattered (guessing i overheated the plastic when the starter started smoking). Worn down brushes too.

That said, am looking for the proper replacement right now. Havent been using the car since I found out I have the wrong starter.

to pull those diesel starters with the brace and all.

i would do some checking first. someone here must know or have a couple off cars they could check.

or, did you turn your old starter in already? if not i would go where i bought the "wrong" one and ask for one to compare. putting the noses together on them you should be able to check length etc.

it seems as if it were wrong it would be making noises.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

...from the store, exchanged the old one. Compared em both while they were out. The 603 starter has 10 teeth, while the 617 starter had a smaller diameter bendix gear, shorter in height too, with 9 teeth. Big differences...a wonder it didnt crunch like cereal when I started the 603 with it! Oh well, interesting experiment...if ever your 603 strands you somewhere with a dead starter, an SR67x will get you home in a pinch!

they would make it so that it would work at all!
if it is that different.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.