240D vs 300DT starter motors
 

I have a used but supposedly good starter motor but not sure of it's origin. How do you tell the difference? What are the Bosch p/n's for both? Are they stamped into the case?

they are the same

Not always, there is a higher output version for the 617 as it is a larger motor, more to turn!

It would make sense to me that they are the same. Displacement of one cylinder is what determines need on a starter.....you are only compressing one at a time.;)

True, but a bigger engine still has more rotating mass to get going.

A V8 with smaller displacement cylinders is still going to have a larger starter than a 4-cyl with slightly higher displacement cylinders.

It has been posted on this forum in the past that the turbo motor starter spins faster than an NA starter. I'm pretty sure that when I was looking for a starter for my 77 300d, that there were different listings for the two engines. I chose the turbo starter. A quick comparison on Fastlane would probably reveal the differences.

Any good and cold day will tell you that the drag on lubricated surfaces has a large effect on starter load as well.

I have 3 from different cars in the garage and they are all the same. The reason the turbo spins faster is because it has lower compression.

Dan

300 starter choices...
http://catalog.peachparts.com/ShopByVehicle.epc?q=1984-Mercedes--Benz-300d-Engine--Electrical&yearid=1984%40%401984&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6192%3AED|10000135%3AMB C|1504%40%40300D&catid=240798%40%40Engine+Electrical&subcatid=240894@@Starter&mode=PD
240 starter only choice...
http://catalog.peachparts.com/ShopByVehicle.epc?q=1978-Mercedes--Benz---40d-Engine--Electrical&yearid=1978%40%401978&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6138%3AED|10000129%3AMB C|1489%40%40240D&catid=240798%40%40Engine+Electrical&subcatid=240894@@Starter&mode=PD
both are the same starter, the choices are for trap ox locations etc, I think the solenoid is clocked different.
now it's possible that they just carry the starter that works in the 240 as well to lower inventory. you would have to go to mb to verify original part numbers on the starters to see if OE starters are different.

They sure look the same to me. You'd think you'd be able to see the beefiness, if there was a beefier starter.

I don't think thats the case....and if it does....its very minor

CR is same for turbo and non turbo....perhaps .1 different.

I forgot I have a copy of the Mercedes Technical Data- passenger cars 1981, which has specs for all models in 1981 in one place!

for 615, 616, 617. the starter has the same Bosch # 0 001 362... and Bosch designation IF 12 V 2.3 KW

It also shows a short circuit test of 500-600 amps @ 3.5V and 660-820 amps @ 4.5V for cars with manual transmission only.

I suppose you put the car in gear, with parking brakes and brake pedal engaged and crank the starter while measuring the current and voltage?

There's also an idling test for vehicles with a note 2) for vehicles with right-hand drive:

amps 95
voltage 11.5
min speed 1/min 6500
min input voltage solenoid switch terminal 50, voltage 7.5 V

I suppose this is the free spinning no load rpm of 6500 at 11.5V and 95 amps?
But why a note for right hand drive vehicle only???

Maybe the more powerful 617 starters came in later model years? If it's more powerful, shouldn't it weigh more and that may be one way to differentiate it?

As i stated before they are the same ;)

So then why are some people saying the turbo 617 starters spin faster?