Mercedes OM617 Powered 110 Build Up

OM617 Prototype

We had been working on the Mercedes OM617 5 cyl Turbo Diesel conversion for several years. The first conversion was in a 109 that originally had the Rover I_O_E 6 cylinder. It needed a thick adapter to push the engine out from the concave bulkhead, but the same adapter put the oil pickup for the sump right over the tube of the front diff, so it was clear a thinner adapter was necessary. The breakthrough came through this summer when we were able to shrink the adapter width to just under 2 inches.

Then we needed to keep the stock oil filter housing, so added a slight tilt to clear the bulkhead.

We were also prototyping the same conversion in a Series III, 88 and had an engine installed in a second vehicle making the prototyping that much more complicated.

Flywheel

Flywheel shown next to the original Mercedes counterpart from an OM617 automatic setup.
Designed for the Land Rover pilot bushing and drilled for the Land Rover Clutch, but uses the stock OM617 ring gear.

The Adapter

Thin adapter stiffened with a steel backing plate.

Custom Oil Pan for the 110

With the oil pickup just behind the front diff tube, designed a custom oil pan.
The top half is cast and the bottom constructed. This was not easy, but eliminated the clearance issues and could be easily designed to compensate for the slight engine tilt necessary to keep the stock oil filter housing with the stock oil cooler lines and all the thermo valves and spring loaded this and that...

The back of the OM617 stock oil pump housing is cast as one piece that includes the oil pickup assembly. In order to build a rear sump, it requires manufacturing the back half of the oil pump from scratch in order to take a long pickup tube. I did this successfully years ago (for a Classic RR conversion) that never went into production because it was too expensive to produce.

Note the baffle to keep the oil from running back when on a steep incline. The oil pump is complicated with a relief valve that recirculates unused oil making it great for off-road use. This is unlike most oil pump designs that simply dump unneeded pressure and volume back into the sump area of the pan.

So you can see how important it was to space the engine back enough in both the 110 and the Series III, thus the short adapter shown above...

In the 110, to clear the front diff (eliminating the need to modify the suspension).
In the Series 88 & 109, to clear the stock radiator and leave the stock 4 cylinder bulkhead and transmission unaltered and unmodified.

Ready to install

$300 Engine out of Pick-N-Pull ready for a test fit... still has the junk paint markings on the front of the valve cover.
The only thing the engine required were new glow plugs and a valve adjustment.
We used a gear reduction starter which started the engine for the first time without any glow...
Ten minutes after this picture was taken the engine started when we were testing the starter, fell off the cart, and required me st scramble to get a hand on the throttle linkage to shut it off !!!
Sounds a little funny now, but was scary at the time.

110 Motor Mounts

Used the later and larger "hydraulic" motor mounts that bolt to the stock 4 cyl frame mounts.
In the 109 prototype of 2010, at idle the engine shook the bodywork violently until we used the thinner stock mounts from the 300D. Since I was making the mounts anyway, decided to go with these mounts. The result was very little vibration at idle and none at speed.

Up and Running 110 Daily Driver

It has about 7,500 miles now and with intercooler and boost set @ 14 PSI runs at about 73 - 75 MPH on flat ground.
Economy is not fantastic coming it at around 20MPG combined driving. Less when your foot is deep into the petal to stay above 70 MPH. Haven't tried any alternate fuels yet in this setup, but ran our 300TD Wagon with the same engine on a little WVO here and there and it always ran fine. The prospect of free fuel is interesting and when ever I have some time will look into it more closely.

110 Body change

After pulling all the carpet and cutting the rear door in half (more later).
Picture of the end result...

Will be installing AC this spring using the Mercedes AC compressor and a 300TDI Defender under dash interior unit (more later)

Series III Radaitor Clearance Picture

Series III Radiator Clearance Picture with stock radiator. Pusher fan needed, but plenty of room to pass a fan belt through between the water pump nose and back side of the radiator. In the IIA, the thinner Series III radiator is required.

I was behind your group at Conclave when the Series needed a pull. Nice D-110 and conversion.

Conclave

Yes the 110 Pickup ran all over the trails... it was the real test and with all those rocks to go over we had no oil pan clearance issues, so all the measuring and custom work paid off. It also climbed pretty well considering stock suspension and 40 PSI in the tires.

The Cove was a great event... auction was slow and not managed very well, but we got through it and still had fun. The trails were good and it was also nice to be in the company of Mike VanCuren, who passed away shortly thereafter. I miss his friendship and visits...