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Mercedes OM617 Powered 110 Build Up

134132 Views 400 Replies 55 Participants Last post by  Ephry73
The starting vehicle:
1986 110 with 2.5 liter Petrol engine, leaking fuel tank, and interior and under hood area covered in carpet and other sound deadening material.

Purchased from a UK dealer. It was used by DRA for flight testing of countermeasures equipment. Unique in that it had 44,500 miles and was without front vents presumably to cut down on noise and interference.


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RD oil pan porn....

This is just a test fit and makes me feel better having on and leaving the engine unattended. There are 28 bolts that hold it to the block. Not sure how that compares to the Rover pans. There are 2 studs at the front that have to get pulled - M8 sized - and replaced by an Allen headed bolt. It's is too bad this is on the bottom as it is going to look pretty trick with the aluminum and Allen heads.

The front harmonic balancer bolt was a mo-fo to get off. I read that it is on at 250lb/ft. A trip to Advanced Auto got me a puller that used the M10 bolt holes and that came off easy.

I am having a tough time with getting the dip stick tube out of the old pan. Need to research that some more. I feel like once I get the front seal in, half the back rope seal and the pan on I will be at a very nice point. After that I am going to pop it into the frame and do the smaller items there so I have some more shop room.
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Being an old school bike guy, I'm a bit disappointed that the pan isn't purple or rasta anodized. -Jeff
Haha - i could just use some old Ringle' , Cook Bros, or Kooka parts as a guide!

------ Follow up post added March 1st, 2014 09:16 AM ------

Nice pictures. We have a special tool to remove and install the dipstick if you need to borrow.
Let me look into the removal - after looking at the pictures I might have a something that will work and i think I was going at it a little wrong. For the dipstick install would a open end spanner work?
Did a little more to the 617 today:

New spacer ring installed. The old spacer ring had a groove cut into it from years of use. It was a little bit of a pain to remove. I had to use various thickness of screw drivers, chisels and sockets to get it off the crankshaft end. To get the new one on I smeared Rotella on it and it went right on.

I had to cut the dip stick tube about an inch. I got it off the old pan by heating things up and it came right out. I think I will hear the pan a bit and then pop this back in. Will do that once it is in the chassis.

Pic of the rope seal on the RD oil pan. This is half of the rear main seal. There is a procedure to slightly move the crank and get the other rope seal in but I really don't feel capable doing that right now. If I have a leak I will worry about it later. My thinking is (since these motors can be had at a decent price at times) if I find another at a good price I will just do a complete rebuild and swap that in, if there are any issues with this one.

The rope seal has to be cut 1-2mm above the pan surface. What is very slick is the RD pan has the same small spike that keeps the rope seal in place.

I looking to seal the pan and install tomorrow. And maybe even get this bear into the chassis using those big ol' Merc motor mounts.
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Got the pan on today.

A couple of pics of the front main seal. The seal I bought was from Corteco. I have used them for axles on the Rover and they seem to work well. Anyways this one had me stumped as the seal had half a flange. When I put the pan on it seems to make more sense. The longer flange should be with the pan as the pan sits back a bit (like only 1mm). I tried to take some pics to show how it sits (which I am hoping is correct)

The 28 or so Allen head bolts. I didn't see the lock washers at first and used blue loctite. But then found them when I was looking for something else. Took them all out and reinstalled with the lock washers. The stock wavy washers can't work as the drill outs are too small. With the lock washers the bolt heads stick out a little bit. I torqued all the M6 bolts to 10 N/M and the 4 - M8 to 25 lb/ft or 32 N/M.

I am having an issue with one of the M6 bolts near where the dip stick goes. Not sure if i should Dremel a notch in the dip stick part or open up the hole for where the bolt goes in. Robert any ideas?
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. You can relieve the dipstick boss or just tap the bolt "around the corner". It won't bend if you are gentle with the taps.
I got it done today. Did a little relieve mostly as the head of the bolt was digging in but I didn't have to remove much.

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Got one of the motor mounts in today as well.

I tried it with the studs from the original motor mounts but the new mounts seem to thin - RD kit is steel plate vs Merc cast aluminum. This is a pic with them taken out.

Here is what the stud looks like - besides the one side being very long the threaded part isn't deep enough IMO.

Had some shorter 10.9 grade M10s. I used them with the stock Mercedes wavy washer and a normal washer to take up a little space.

All install - this is the left hand side but the motor is still flipped upside down.
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Pay close attention that one of the stud holes from the stock mounts because it is not captive and goes all the way through the block. Believe it to be on the other side of the block. The bolt cannot be too long because it protrudes inside the engine. Also best practice to use some gasket sealer on that particular bolt & hole.
Thanks Robert -

Not sure if I said, but this mount is for the left hand side of the block.

I might pull those bolts out and double check to see if the clearance is exactly the same as the studs I pulled out. If they aren't the same length I will get some shorter bolts. I will poke the holes and see which one goes all the way thru and gasket sealer that one up.

Put the engine in the chassis today.

Left side motor mount. I pulled all the bolts and took off a few mm in lengths. I checked all holes and did not see one that went into the block but one did have some oil. Not sure as things were leaking all over. IIRC it was the upper left one on the right hand side.

I did a "dry" fit of the RD plate and the spacer. I put in some of the bolts to see what was going where.

View of left hand side

I had to get a new alternator bracket as the one that came with the engine had one of the pieces that hold the alternator crack off.

Right side motor mount. You should be able to see the heat shield to protect the motor mount.

Brass fitting for turbo drain. Need to figure out how this will be refitted.

View of the RD plate where the starter will go
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That's pretty sexy. Who makes those shock towers ?
Thanks! I was pretty stoked to get it in the frame today.

RTE shock towers. I bought them from someone on the board and sprayed Eastwood etching primer and chassis black extreme on them.
Are you going to install AC?

I am not. I want to keep things simple and when I had my '95 ST I only felt I needed AC a few days of the year.

------ Follow up post added March 11th, 2014 01:33 PM ------

Note that the mounts move only in one direction.
They are stiff in the all rubber areas, but move where there is less rubber.
Looks line left side will allow front to back movement and can't see the right mount.
Recommend they be installed to allow side to side movement, but not front to back.

Thanks for that - both of them are installed incorrectly then. I will move them both 90 deg.
Got the starter in. It needs the adapter plate to fit correctly as I soon found out. Goes together like butter when all the pieces are used.

Also got my shorty R380 in from the guys down in ATL. Had the bell housing mocked on before the trailer pulled out of the street.

I was a little puzzled on how the flywheel worked and went together. After some web searching and looking at Robert's pics at the beginning of the thread I put together that the stock flywheel is 2 pieces. It has a ring that needs to be popped off. I stuck it in the freezer last night and heated it a bunch this morning. A little hammering going around the edge with a flat nose punch and it came off.

I wire brushed the ring - then heated that on its own and it slipped right on RD's flywheel. I needed to hammer the last couple of mm down flush but wasn't bad. Looks really trick all done and a shame it will be covered up. I will install it later / just need the M10x1 tap to come in today (I buggered some threads a but on one of the holes).

Parts are coming in from Mercedes Source today so I hope to install some pieces onto the motor tomorrow. I am really itching to fire it up and hoping I did everything correctly.
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Working a little on it today.

Read a little about the EGR delete. And it seems like a worthwhile move.

First pic is the EGR valves which have a tendency to stick from what I've read.

Pic #2 - is the EGR valve and piping taken out. Along with some of the coolant piping to replace that rotten hose piece.

Pic #3 - the inside of the plenum with all the build up I guess from a stuck EGR valve.

There isn't much to blocking things up but I have so many little project that it seemed easier to just buy this:

MercedesDiesel4x4 also has a plug and play oil cooler kit. I might get that eventually. Again, could be cheaper to make my own but I have a lot of work already.

Found this build thread when I was searching OM617 info:!/page2

I like how clean it looks with the lack of items.

Question to Robert or any other 617 wizards: how much of the vacuum line system can be removed?


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In your case regarding the EGR vacuum line, all of it. You can tap and plug the exhaust manifold with a pipe plug or if you send it to me, I can have it welded by a shop that can weld cast iron. Didn't geta reply on the last email from you regarding the new transmission mounts and kit shipping.
Just sent you an email - I missed one of them.

Thanks for info on EGR. I think that kit has piece to cover the exhaust manifold. Would love to take you up on that weld offer but save that for the next motor/build.
I also got these items in recently:

Rotella T6 - 5W-40 - it seemed people on the Merc boards ran this or the Mobil 1 truck diesel stuff. This was a little cheaper and people on here have had good experience with Rotella.

Mercedes Shop Manual - got it off ebay for $40 or so. There is another one but I am not sure it includes the turbo motors.


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I am double posting some items from my build thread. I meant to post here originally but messed up.

I got some items done this weekend.

Pic 1 - EGR plate on intake manifold
Pic 2 - EGR plate on exhaust manifold. This needed a little playing around with. I used cooper gasket seal on both.
Pic 3 - pic of thermostat - I had some polish and a cloth wheel and did a couple of pieces up. It was more of a PITA to get the grease/grim off than to polish. I think paint would have been more work. Hope it stays like this for a little while. I also got a new rubber hose which definitely needed to be done.
Pic 4 - backside of thermostat
Pic 5 - front of the motor right now.


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Catch Can & Hot/Cold Air Intake

Came across this and wanted to bookmark it for the future:

I am not totally sure how I am going to handle air intake and the oil catch.
Add-on to the air intake link I posted yesterday. Intake clamps and tube site:
I have been lacking on this but should be jumping in with some work over the next few weeks. I would love to get it test running soon.

Very minor but I got the turbo drain done. I took off the drain, cut, wire wheeled it and painted with the engine paint I used on the block. I got some 3/4" Flex Fab silicone hose from Napa (- part number-5526-075) and stainless clamps.

My next steps are to get the oil cooler lines built. I have to weld some bungs to the stock Merc lines and order an adapter from the 200tdi radiator so I can run AN lines.
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Sum bitch - don't think that heater hose is oil compliant. Should have researched it before I cut and installed but figured the guy at Napa knew what was up when I brought the parts in and said I need a turbo oil drain.... I will see what McMaster has.
I used low pressure hydraulic hose.
Thanks - will swap out soon before it gets more items out in and harder to access.
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