Hi! First post from Wyoming. Need help with conversion. - PeachParts Mercedes-Benz Forum

3jvj · #1 11-17-2010, 08:42 PM

Hello! Love the "do it yourself" aspect of this forum, and I'm hoping that there is a decent knowledge base to help me with a project I'm working on.

I'm transplanting a 79 300 turbod diesel into an 83 380 sel.

I've got the 380 stripped, and I'm almost done pulling the 300/trans, and I'm not too familiar with what step I'll need to take to make this happen.

At this point I would like to convert whatever wires I will need before I stab the motor, as they are easier to get to right now, and here are my concerns:

There is a wire connector on the 380 trans that doesn't exist on the 300trans, and a cable on the 300 trans that isn't on the 380 platform.

Can anybody tell me what I'm in for here?

Thank you- Josh

I have a lot more concern/questions (speedo, vac., etc.), but I feel the transmission wires and vac are the first things that I should modify.

3jvj · #2 11-17-2010, 09:10 PM

b.t.w; If there is a more appropriate place to post this, please let me know.

I've been posting questions on benzworld for months, and I'm still just goole searching the interworld in vain.

junqueyardjim · #3 11-18-2010, 07:59 PM

There is quite a little swap information in the diesel section, but I don't recall a switch over like yours. But I think it could be done, if you know pretty well what you are doing and what you wish to accomplish. Most of the swaps are diesel to diesel, and some are quite complicated.
Usually on these more difficult swaps a number one need is to have access close by to both vehicles, the donor and the keeper. Parts are parts and there always seems to be a shortage somewhere. You are staying Mercedes so that is a plus. The 83 "S" class was available with the 617 turbo and there is a lot of info on that car in the diesel section. It might have a better rear end ratio for your engine. If you can locate a "S" with a diesel in a junk yard it might be very handy for some parts and if it isn't to picked apart it can be helpful for wiring and vacuum especially. So have at it. Get the camera out and take a lot of pictures so we can all see what you are doing. I am finishing putting a 617 Turbo into a former 240D with a 4 speed, and I think that would be easier then what you are doing. But there are plenty of parts around with members parting out car and plenty of good solid and good natured advice available when you need it.

Gilly · #4 11-18-2010, 09:09 PM

Just what I was thinking too, find a sdl to use for parts, you will need a lot of chassis parts from one.

SD300 · #5 11-19-2010, 08:44 PM

u may run into engine mount issues, as w 126 body has turbo diesel from fact.

when u pull out the engines u can measure the difference in where it will sit.
i was told by a guy who does these conversion, u need the torque converter from the diesel as its stronger than the gas 380, mind u the 380 has even more hp than the diesel.

the rear end can be fun part, as 380 is a higher rev engine, not sure what u need to do, u may not have a lot of top end/ speed.

i have a w126 280se sitting here and wanted to drop a dsl in it too, but just too much work.

i have bought a 85 500sel several yrs ago that has a reg 300d in it.
i think it has a diesel trans with it, so i didnt have any speedo and oil pressure.

the car was very slow, as it has not turbo, 80ish HP, and a 500 has 230+ hp, that was a euro version so it got more oomph.

so good luck , God bless is all I can say.

3jvj · #6 05-11-2011, 11:42 PM

Bump. Winter is over, and I'm going back in.

I'm an hour or so away from pulling the sd motor.

Thinking of going with this to get around a dash swap, but I'm wondering if there is an adjustable pulse generator out there to fine tune it. I think I'm keeping the 380 rear end in it.

Also need to figure out the shutoff system. The 300sd has never worked, and I'd like a switchable option (relay).

junqueyardjim · #7 05-12-2011, 01:37 PM

Work it out before you spend good money for stuff you may not need. It is pretty easy to switch differentials on these cars, so talk about it, try to find out exactly what gearing you have and do you want to keep it. That 380SE had a high speed rear axle, higher then the diesel and some one will come up with the numbers. I think it would be easy to live with either rear axle, one would give a little more top speed, the other would be a little better off the line. Regarding the speedo, you can keep your dash pod and just insert what ever speedo in there that you want. They are held in there by three screws on the back. But remember your speedo is tied in with your rear axle ratio, so use the correct speedo that matches the rear axle. You probably have a blank indicator spot on the bottom of the 380SE dash that could be used for a glow plug indicator light, but you would have to bring the wire along - not to much of a problem, and I think a person could live without the indicator light. You would have to remember to give it some glow time, especially in very cold winter weather. That can be difficult for people if they are impatient. I don't think the motor mounts or the motor mount legs will have to be modified. I think they will work out just fine. The cable on the diesel transmission is the "bowden cable" and it ties in to the throttle linkage and manages the transmission shift points. If is is cut or broken you will have to get a new one. It probably has vacuum for a modulator to soften the shifts.

junqueyardjim · #8 05-12-2011, 07:09 PM

Engine shut of is a very simple vacuum switch mounted to the ignition switch. Your 380SE might even carry one along that is not needed, but I doubt it unless the ignition assembly has been replaced by a used switch. But anyway, install a used switch body with your key switch installed, and make sure it has the vacuum hook up. Then of course you will have to run two vacuum lines, one from the vacuum source to the switch and then a line from the switch to the shut off on the injection pump.

vstech · #9 05-14-2011, 12:03 PM

I think you will get more responses over in my forum. If you don't mind, I'll copy this thread over in the diesel discussion.

Stretch · #10 05-14-2011, 01:49 PM

Can you tell us some more about the OM617 you are about to pull / have pulled?

What is it coming out of?

What other parts do you have with the engine?

Which transmission are you mating to the OM617?

Which motor mounts do you have?

And post us some pictures - we like pictures over here!

300D85 · #11 05-14-2011, 04:06 PM

Quote:

Originally Posted by 3jvj

I'm transplanting a 79 300 turbod diesel into an 83 380 sel.

dude was selling one in my neck of the woods though I didn't go see it

sixto · #12 05-14-2011, 04:36 PM

The 79 SD transmission uses a mechanical speedo cable, the 83 SEL speedo and all W126 speedos use an inductive signal. Swapping an 81-84 300SD transmission and cable might be easier than customizing the SEL cluster to take a W116 or W123 speedo.

W116 and W126 300SDs use a 3.07 rear, a 380SEL uses a 2.47 rear. It'll be slow going off the line and passing but you should get better high speed mpg. Probably intolerable if it's hilly where you are (never been to Jackson Hole). Try the 2.47 then swap in a 3.07 if necessary. 3.07s should be easy to find with the number of W126 300SDs out there.

If the 79 300SD brake booster vacuum hose isn't long enough, obtain a hose from a W126 300SD so you can connect the engine vacuum pump and brake booster. The hose will have a fitting for auxiliary vacuum for the ACC and engine shutoff (W126 central locking uses a dedicated electric pump). There's no way to make a gasser vacuum hose work.

You can use a common switchover valve such as an 80s MB Diesel overboost protection solenoid for engine shutoff. Plumb it so source vacuum goes to the engine shutoff actuator on the IP when there's no power to the solenoid. Wire it so the solenoid is energized when you turn the key to run and start. I've never done this but I read it works.

Sixto
87 300D

kerry · #13 05-14-2011, 05:06 PM

You'll need to have a means of bleeding off the vacuum to the shut off valve in order to restart it once you shut it down. I'd be tempted to swap in the whole ignition assembly off a diesel 126 so the key operates the vacuum shut off.

sixto · #14 05-14-2011, 05:27 PM

The overboost solenoid should vent the ALDA branch when energized because it wouldn't be worth much if it trapped boost in the ALDA when closing off the manifold signal. Am I missing something?

Sixto
87 300D

vstech · #15 05-14-2011, 07:01 PM

overboost valve works properly, it vents, and holds vacuum just like the switch would.