Frankencar-1993 300d sedan/1994 e320 wagon diesel conversion?? - PeachParts Mercedes-Benz Forum

Hogweed · #1 06-29-2013, 10:57 PM

here it is: i recently bought a 1994 w124 gasser wagon w/ a bad trnny but in fantastic shape otherwise. today i picked up a 1993 300d that has some potentially preventative-for-restoration issues but a good 2.5 turbo motor and tranny.
my question is how insane would i have to be to put the diesel driveline into the wagon? remember, i'm pretty insane and hate money so keep that in mind.....

greasefire · #2 06-30-2013, 08:13 AM

Hey I want to do the same thing. I've got a 91 diesel with serious rust issues and diesels are hard top find but 124 gassers in nice shape are plentiful. My diesel runs with out any electrics except the idle drops so I think it may be pretty straight forward to get a running motor in there. I need to go to the wreckers and see if the 124 chassis changes much with the power train options. I believe only the motor mount brackets on the engines change not the position of the mount itself. A little gas in the diesel never hurts much so the tank should be ok but needs a return line. The turbo doesn't need all that boost control egr valve inlet flapper sensor stuff. Maybe just the over boost protection. Also the idle control circuit on the back of the injection pump bothers me a bit.I don't know where that is linked in.

pwogaman · #3 06-30-2013, 10:17 AM

It should work without too much difficulty. Potential issue areas include the motor mount fittings and the drive shaft length. The diesel also has the extra oil cooler under the left fender.

ROLLGUY · #4 06-30-2013, 10:22 AM

It would seem easy enough to do if you put the 2 cars side by side and started swapping parts. I would think the entire wire harness should be swapped over, and would be the hardest part of the job. I believe the entire engine/trans package should be a direct swap and bolt in with no problem. I would like to see this done. A 2.5 turbo wagon would be cool!

BrianCostello · #5 06-30-2013, 01:50 PM

You can and should do it!

greasefire · #6 06-30-2013, 04:57 PM

Thanks for the encouragement. I don't know if I would want to swap the wiring harness though? The only electrical connections between the motor and the rest of the car are the engine oil and temp sensors coolant temp starter alternator glow plugs(ok thats a lot) All the lights and wipers and control what not shouldn't mind too much which motor is pushing the car along. I will bring across the feeble transmission and drive shaft. I am a little concerned about the shifter linkage. As well on the back of the ip pump is an electrical device which I suspect has something to do with idle speed? Does any body know what this is and how it controls .

ROLLGUY · #7 06-30-2013, 05:54 PM

Quote:

Originally Posted by greasefire

As well on the back of the ip pump is an electrical device which I suspect has something to do with idle speed? Does any body know what this is and how it controls .

Yes, idle control. You could truly make it a Frankencar by hooking up everything separately that is different, and manually switching the idle control (I am sure there is some box somewhere that controls it electrically) and engine shutoff.

Hogweed · #8 07-02-2013, 08:54 PM

any other thoughts or possible concerns? maybe i can coax renntag up here....he's just the genius i need for something like this

jay_bob · #9 07-03-2013, 08:39 AM

You don't need to swap the entire car wiring harness, just the one in the engine that runs between the EDS controller and the engine.

You would also need the glow plug relay and harness.

The electrical manuals are on startek or w124-zone.com I would study those and see what is in common.

ROLLGUY · #10 07-03-2013, 12:00 PM

Quote:

Originally Posted by jay_bob

You don't need to swap the entire car wiring harness, just the one in the engine that runs between the EDS controller and the engine.

You would also need the glow plug relay and harness.

The electrical manuals are on startek or w124-zone.com I would study those and see what is in common.

That is nice that each harness is separate so this can be done easily.

thayer · #11 08-18-2013, 02:11 PM

Do this. Take pictures, I want a 606 in a 95 wagon.

t walgamuth · #12 08-18-2013, 02:51 PM

and the vented rf fender.

sixto · #13 08-18-2013, 05:14 PM

You're on your own for a driveshaft since no US wagons came with the 722.4. A 722.3 such as from an 87 300D or TD will bolt to the 602 but there's still the length issue since the 602 sits further forward than the 603. Review pictures of 250TDs on European eBay sites to determine whether the SLS pump is driven by the cam or is part of a tandem pump. You'll need to convert the 602 to a pressure control wastegate to reduce dependence on EDS. Hopefully you can swap the E320 tumbler into the 2.5 key switch so you have engine shutoff function without a separate key.

Sixto
87 300D

greasefire · #14 08-30-2014, 01:46 PM

Ok so its done and works fine. I have a very clean 1990 300e with a 2.5 turbo diesel engine and tranny installed from a very rusty beat up donor car.
Issues
1) throttle cable needed swapping
2) Manual idle adjustment as the electronic idle control circuit is not available
3) transmission output prop is different so save the front drive shaft it just bolts on fine.
4) shift linkage has to be stretched an inch or two
5) couldnt find the aux fan control or it never worked so I got an after market job for $50
6) Fuel lines just hook right up there is a supply and return on both cars.
7) electric fuel pump on the gas but not on the diesel. I suppose I should bypass this pump but have not yet .There don't seem to be any issues here. It only runs for a second then shuts off for the rest of the day. 2000km so far
8) all that vacuum nonsense to control boost and egr. Most of this got thrown out. I kept the vacuum stuff for the transmission shift and fuel shut off. I used a normally open solenoid and a normally closed solenoid to apply vacuum to the shut off on the injection pump. I found these in the vacuum stuff I stripped off the car. I could not find a way to wire this to the ignition switch so I mounted a small push button in the ashtray.
9) Glow plug relay.. I just ported over from the donor car. Again I put a small switch in the ashtray. James bond you say?
10) Stock air filter had to be replaced with a K and N .
11) heater and rad lines need some minor plumbing I used 1 1/4 copper fittings where needed.
12) rads just swapped over engine mounts are the same transmission mount bolts right up.
13) The rear end on the diesel is taller than the rear end on the gasser but I just left the gas rear end in for the time being. But turns out I like the gas rear end better. The car is a little jumpier at lights. The speedo error is very small not an issue. At highway speeds the revs are 280 rpm higher.
14) No tach I needed to get an after market diesel tach.
15) turbo boost control I just fixed the waste gate shut. The most boost iv'e been able to squeeze out of this old turbo is 10 psi.
Don't throw the old car away until you have pillaged it for all the parts you need.
Over all this is a pleasant afternoon project that took me weeks.
In advance I'd like to apologize to the purists out there.

Mölyapina · #15 08-30-2014, 02:28 PM

Congratulations! Sounds like you put a lot of hard work into that swap

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