I recently put together a Bosch 2.2 kw gear reduction starter for my OM616. The starter uses the same 2.2 kw planetary gear reduction motor used on the OM60x engines but with a 9 tooth pinion and a different nose and solenoid. It fits perfectly and works well. It's more compact and at 13 lbs. 5 oz. it weighs 9 lbs 8 oz less than the original Bosch. The 30 deg solenoid angle is the same as the original starter.

Before anyone gets too excited bear in mind that this starter does not exist as an off the shelf item. It must be assembled. That said there are two off the shelf parts that may work depending on your application and your willingness to make wiring changes.

The basic starter I used is the Bosch SR-97X as used on VW 2.4 liter diesels. These are found in the US most commonly in Volvos. This starter has a nose angle of 9 degrees and will not clear throttle and transmission linkage used on older OM61x engines. Later engines with vacuum transmissions and revised linkage can use the VW/Volvo SR-97X starter directly. The only remaining significant difference is the solenoid terminal which is a spade type. Be advised that the SR-97X starter may be supplied by Bosch as a Hitachi offset gear reduction starter. The Hitachi will likely work on later engines but will not clear early linkages.

If your car is a W115 or early W123 with linkage on the passenger side you will need a 30 degree starter nose. Fortunately a 30 degree nose was used on 2.4 liter diesel equipped VW LT series trucks in Europe. I was able to obtain the entire starter used and it fits perfectly except it too has a spade connector. It should be noted that not every VW LT truck uses the 30 degree starter, some use the 9 degree. I wasn't able to zero in on the distinction.

I didn't want to alter the wiring in my car in case this experiment failed so I exchanged the solenoid for one with screw terminals. The solenoid from a Mercedes gas engine with a passenger side starter will work. I found a NOS one for an M110.

The VW starter nose was originally equipped with a bronze bushing. This has been replaced with a needle bearing (INA Needle Bearing HK120, 6007023)This bearing is used on later versions of the VW 30 degree starter as well as Mercedes OM60x starters.

Since my car is a W115 I used the 30 degree nose with a new bearing, the rebuilt SR-97X motor and the NOS M110 solenoid.

The tests were conducted on my W115 with the fuel shut off and the key in the lock position. For testing the starter was jumped at the solenoid. The current measurements therefore only include cranking amps. For both tests the car had been driven over 100 miles the previous day and had a fully charged battery. In both cases the engine had been off for approximately 12 hours.

The original starter tested was a well performing recent Bosch rebuild. The tests were timed at 10 seconds. The engine temperature was read from the thermostat housing and was taken with a Fluke non-contact thermometer. Current was measured with a Fluke current clamp. RPM was measured using a laser tachometer that stores high and low readings. The average of the two readings is the listed rpm.

I can't get my data table from Word to work in this post so I apologize for the mess:

Original Starter: RPM 202 (197-207), Amps 235 (220-250)
New Starter : RPM 218 (214-222), Amps 265 (steady)

The result of the starter swap is a 9 lb. 8 oz. reduction in weight, an 8% increase in speed and a 13% increase in current. The new starter does not have and does not require a brace. The VW version of this starter has no brace and AFAIK neither does the OM60x version.

It's worth noting that a 9 degree version of this starter was used with the OM616 in the Spanish made MB100 van. The MB100 did use a starter brace (A6161510041). This brace can only be used with the 9 degree starter because the solenoid clock determines the motor through bolt angle. Both the 9 and 30 degree VW versions of this starter are supplied with motor bolts instead of the studs required for the brace.

Also: The VW starter uses a 9 tooth pinion gear and the OM60x version uses a 10 tooth gear. The 9 tooth starter on the OM61x in conjunction with the 140 tooth flywheel yields a 15.55:1 ratio. The 10 tooth OM60x starter and 144 tooth flywheel yields a 14.4:1 ratio. As a result the 2.2KW starter will crank more slowly on the 61x than it will on the 60x but it will have more mechanical advantage which should result in faster cold weather cranking.

I suspect the reduced variation in current seen in the new starter is a result of increased torque. The change in current with the direct drive unit results from the load variation through each compression stroke. The average rpm is the result of deceleration during compression and acceleration after. As a result the average rpm may be composed of significant speed variation through each revolution. The tach would not be able to detect this variation since it measures time per revolution. However a change in load would be reflected in the current variation. That's my theory anyway!

The pictures show a comparison of the original and 2.2 kw starter. The gear reduction starter shown is made from the 9 degree nose and leftovers. The other shot shows the 9 and 30 degree clearances to the block with a heater thrown in. The block is an OM615. The solenoid picture shows the M110 solenoid on the 9 degree starter. I forgot to shoot the finished product!

Attached Thumbnails

         

__________________
1969 220D 5 Speed (OM616)
1983 240D 4 Speed
1985 300D Auto 376K
1985 300D Auto 275K

I put a 616 turbo in a 201 chassis and had to get a smaller starter so I could change it from the bottom..

I went with a starter from a 560sl I think.. I had to machine the nose cone diameter and face to mate the engagement depth right. As with yours, it is a lot lighter, and does crank a touch slower than the oem, but the engine fired up without issue, and it had bad compression lol (currently in the process of rebuilding it)..

I haven't done a current draw test to know how it does, but it is a permanent magnet starter motor so it should be reasonable..

The sight would not let me repost pics that are in a different thread?? Plan-B... lol
Permanent magnet, gear reduction starter mod for 240D

Tell us about your TURBO 616... or did you mean 617 ?

As engines get worn... and have less compression and perhaps less well maintained ... the valves not adjusted right on the money... etc...
given that SPEED OF PISTON travel is what ignites the mixture ( if the glow plugs are out )... that might be an issue...

I have seen my 616 starter apart ... it is so over built I can not imagine modifying it ... unless there is really a need ... like you said about being able to change from underneath on a different chassis... but to save 8 lbs... on a stock vehicle.... I vote for stock overbuilt... and replaceable by normal parts houses methods....

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I meant 616 Turbo.. Don’t want to change the direction of the OP..

It is true the faster you can spin it the better, but when the situation will not support OE, compromises are some times required.. The actual cranking speed is with in hairs (audibly anyway) and it never hesitated to start (when it was going to lol), but I did not run it in the winter time..

This type of information is for individuals doing custom projects, not intended for R&R on a standard car or for purists lol.

I saw your thread when I was researching this. It was one of several that got me thinking about a smaller lighter starter. I also saw your thread on pencil glow plug conversion and chamber volume - great stuff!

I considered a Mean Green but they didn't seem to hold up well and customer service isn't great. The 560SL starter obviously worked well for you but I was concerned about the 1.7kw motor - especially during the VT winter. Plus I don't have access to a machine shop.

Once I found out I could use the 2.2kw Bosch gear reduction motor from the OM60x I decided to try it. I thought if that starter can crank the 3.5 liter OM603 then it should work on any OM61x. It cranks faster than stock, it's smaller and weighs less. It was hard to build but if it fails I can use the motor assembly from an OM60x and install it in my nose or put the stock unit back on. I usually rebuild my own starters and alternators so this works for me but might not work for others.

I've only tried this starter on the OM616 but I just picked up a 1980 300TD so I may get a chance to try it on the OM617 at some point.

Regardless, the original is very good and I would stick with it unless you need the space or are obsessed with efficiency and weight reduction. I'm in the latter camp. I've also shed another 9.5 lbs by substituting a Kubota 40amp 93mm Denso alternator for the Bosch.

BTW: What kind of fuel economy did you get with the OM616 in the lighter and more aerodynamic W201?

__________________
1969 220D 5 Speed (OM616)
1983 240D 4 Speed
1985 300D Auto 376K
1985 300D Auto 275K

cool work!!

__________________
'77 240D, 504H, OM617.952, etc.

Am curious if this starter worked and lived in the 300d? Ready to do the same now. Please update us on your fine work.