Diesel RVs: Re: [diesel_mercedes] Re : question re engine swaps

If Trish and Nate haven't sufficiently scared you off of this project, let me chime in with some observed specifics:

The two things that are going to be "gotchas" are the transmission and exhaust system, with the starter wiring as an adjunct to the exhaust system.

The transmission for the '79 is the old 622.01/02; the four-bolt pan. It is quite different from the 622.03, six-bolt pan transmission used after '81. There's going to be a difference in kick-down linkages, and the later transmission will have a vacuum modulator. AND, as Nate pointed out, the transmissions used in the W126 had electronic speedometers, so, there's that issue to contend with as well. Best, as far as connections go, would be to use the transmission out of the '79. (Although the four-bolt pan transmissions found behind the turbo-engined SDs of the '70s cars had a wider, and therefore, beefier, rear clutch pack and rear band. But that may be more for the extra weight of the W116-chassis SD than for the extra power of the turbo.)

If you decide to use the SD's six-bolt pan transmission, you'll have to get the mechanical speedometer drive from a later, turbo-engined W123 300D, '81 through '84. It's possible the drive from a same-era 240D will work as well.

Which brings us to the exhaust system. Of course, the '83 SD engine has a turbo, while the '79 does not. You'll have to do some creative cutting/wielding to get the '79's exhaust system to bolt up to the turbo. Once that is done, you may very well find, as Trish did, that the cables to the starter will be too short to reach past the turbo piping to connect up.

Finally, there may be differences in the radiator-to-engine connections. I'm pretty sure the '79 has the old, series-wired, "loop" glow plugs: not a deal breaker in itself, but you'll need to swap the glow plug wiring from the '83. Oh, and you'll have to properly attach the SD's "TURBODIESEL" badge to the back of the '79....

Having both cars, complete, will go a long way to getting past a lot of this. The dedicated would probably want to swap the starter wiring from the SD into the '79, for instance.

As Trish advised, if you have the time, patience and are OK with having the car(s) laid up while you tackle the job, then, you may come out just fine. Certainly, don't expect to MAKE money on the endeavor....

Mark in Lakewood, CO

From: "Trish Dougherty" <purrfectharmonyfarm@wifi45.com>
To: "diesel mercedes" <diesel_mercedes@yahoogroups.com>
Sent: Thursday, August 16, 2012 9:28:20 AM
Subject: Re: [diesel_mercedes] Re : question re engine swaps

Clearing throat here...eh...soon be a serious headache? It'll be a headache sooner than you think. Lots of stuff to figure out. ME? Never again. If you have experience, time, money, something else to drive and patience go for it. Otherwise it's so not worth it. Sure wish I had checked my original motor before I jumped off the cliff into that project.

Trish

On Wed, Aug 15, 2012 at 10:45 PM, Nate <vwnate1@yahoo.com> wrote:

Sort of......

The trannies are different , the '83 W-126 having an electric speedometer and different tranny linkages than does the older W-116 chassis .

At the very least you'll have to swap the entire drivetrain , engine and tranny or this will soon be a serious headache .

-Nate
Brad Asked :
>
> will a 83 300 SD turbo motor swap into a 79 300D (NA) body without too much trouble? Both are slushboxes. I have an SD with a rotten frame but good motor and a guy is offering a 79 that is in good condition but with bad motor.
>