1984 300SD OM617 into 1979 Ramcharger - PeachParts Mercedes-Benz Forum

Madmax55 · #1 12-04-2016, 08:48 AM

Hey gents

I have a big swap question for you guys. I have a 1979 Ramcharger with a NP435 manual trans that I will be doing a 617 swap into.

How would you guys go about this? any advice?

I was thinking find MB 240d flywheel, match it to the OE crank balance on the 1984 OM617 300sd I have. Then make sure the OE dodge/NP clutch will fit. If not source one that works with my Dodge bellhousing and clutch setup.

Regarding the adapter, how do you guage what width it needs to be?

how will the longer input shaft of the transmission interface with the pilot bearing? this is all foreign to me.

Any help would be awesome!!

PS if anyone wants the parts from the 1984 300sd I picked up yesterday let me know! all driveline is excellent shape, just the interior is shot(pretty much)

mach4 · #2 12-04-2016, 09:49 AM

The simplest would be to keep the existing transmission. The second simplest would be to use a Toyota transmission for which there is an existing and tested adapter kit. The most difficult would be to make your own adapter - there are threads about the pitfalls of doing this. You could also use the 240D manual transmission - been done many times.

Your existing flywheel may be matched balanced to the engine (as opposed to being neutrally balanced), so be sure you check that out.

Speaking from experience, swaps are mostly research and exploring different options, then designing and engineering, then fabricating and finally testing....and often several iterations through this loop for each stage.

These swaps have been done many times - Studebaker, S10, Toyota, Jeep, Ranger and the list goes on.

Read through the many swap threads. You may not find your specific answer, but you'll get clues and ideas of how it's been done before.

Oh, and remember the Rule Of Swaps - the last 20% of the project takes 80% of the time.

ROLLGUY · #3 12-04-2016, 12:02 PM

I am planning on doing a 300D 4X4 using the 617 with an adapter to an AX15 (jeep) trans and Dana 300 TC. I believe the same company I got the adapter from makes them for many other transmissions. In fact, your Chrysler transmission might be the same (or similar) bolt pattern as the Jeep (AMC) trans. I don't remember where I got the adapter from, so Mr. Google is your friend here.......Rich

OM617YOTA · #4 12-04-2016, 04:00 PM

Go get a small block Ford bellhousing for your NP435 and then use this:

Ford Adapters

I would take this opportunity to swap in a transmission with a 5th gear, as you'll mostly be there already.

125hp to drag around a Ramcharger will be a bit pokey going up hills and slow getting up to speed while towing.

t walgamuth · #5 12-04-2016, 04:35 PM

But it does have 188 ft lb torque, IIRC.

Dan Stokes · #6 12-04-2016, 05:53 PM

One of the challenges of using a non-Mercedes trans behind a OM61X engine is the flywheel. Never mind the balance issue, this is a dished flywheel similar to those found on some industrial engines and does not easily adapt to non-Mercedes-style clutch assemblies. I also learned that at 224 HP the stock, new clutch assembly will NOT hold the engine's power. I did a work-around using a BMW disc and the stock pressure plate but I'm a bit worried about what will happen with my bigger turbo, this winter's modification.

Just to detail my set-up - it's an OM617 with a Dieselmeken Superpump backed with a Getrag (240D) 4 speed installed in an '85 S-10.

Bottom line - if you can find an adaptor kit you'll be miles ahead. They will have worked out the clutch and other issues and will save you a TON of headaches. I'd try Brentsen's and I know there are others out there.

Dan

OM617YOTA · #7 12-04-2016, 08:13 PM

Quote:

Originally Posted by t walgamuth

But it does have 188 ft lb torque, IIRC.

I think the turbo 617's are 125hp and 181 ft lbs. Looking it up, the straight 6 base engine in the Ramcharger was 115hp and 175ft lbs, and the V8's a goodly bit more.

So nevermind, sounds like the 617 will drag it around just fine.

ROLLGUY · #8 12-04-2016, 08:35 PM

I got my kit from these guys: Jeep Adapters

Madmax55 · #9 12-05-2016, 12:22 PM

Quote:

Originally Posted by ROLLGUY

I got my kit from these guys: Jeep Adapters

anyone have an transmission suggestions that could hold up to my 1/2 ton truck? I know it will only have the 617 powering it but of the available adapters I will need to swap transmissions so may as well upgrade a bit?

Madmax55 · #10 12-05-2016, 02:17 PM

Also, can anyone school me on the input shaft and how far the length affects clutch to flywheel engagement?

My friend has a machine shop, but just am unsure as to how think this adapter needs to be to allo my clutch to interface with the flywheel.

Would you guys recommend i have my dodge flywheel balanced to the mercedes flywheel? or guy a 240d manual trans flywheel?

trying to put this together in my mind and i dont think its actually too difficult but need a little guidance and explanation

Dan Stokes · #11 12-05-2016, 04:31 PM

Like I said - the OM-series flywheels have a recessed center and a step where the pressure plate mounts. Understand that the 240D or 300D flywheel is NOT flat and cannot simply be redrilled to accept a different bolt pattern. This is NOT an easy flywheel arrangement to adapt to anything. It MIGHT (and I stress MIGHT) be possible to machine a Dodge or other flywheel to attach maybe to the pressure plate step but then you still have the issue of the flywheel being pretty small in diameter so the available clutches would have to be fairly small.

If you're running a stock or nearly stock engine I'd think the Getrag or MB-built manual (late or early 240D) ought to be OK. I've loaded my Getrag pretty heavily and there has been ZERO issues with it and mine dynos at 224 rear wheel HP.

I suggest that you look at my build thread (search for my name on this forum) and you can see how I handled this. I think Yoda has some similar info on his with a slightly different approach.

As noted in my build thread, Jags That Run has an adaptor plate that will mate the rear, oddball 3-bolt MB flange to a standard Dana U-joint assembly so you can get a regular American-style driveshaft made, and with a built-in slip yoke. I would NOT mess with the Mercedes (European) style driveshaft for your set-up - WAY too much hassle and no real benefit.

Do yourself a favor and read the PP build threads (mine and others) that cover these types of builds. It'll put you mind at rest and answer a LOT of your questions.

Dan

panZZer · #12 12-05-2016, 06:51 PM

Quote:

Originally Posted by Dan Stokes

One of the challenges of using a non-Mercedes trans behind a OM61X engine is the flywheel. Never mind the balance issue, this is a dished flywheel similar to those found on some industrial engines and does not easily adapt to non-Mercedes-style clutch assemblies. I also learned that at 224 HP the stock, new clutch assembly will NOT hold the engine's power. I did a work-around using a BMW disc and the stock pressure plate but I'm a bit worried about what will happen with my bigger turbo, this winter's modification.

Just to detail my set-up - it's an OM617 with a Dieselmeken Superpump backed with a Getrag (240D) 4 speed installed in an '85 S-10.

Bottom line - if you can find an adaptor kit you'll be miles ahead. They will have worked out the clutch and other issues and will save you a TON of headaches. I'd try Brentsen's and I know there are others out there.

Dan

the 38 lb car flywheel and the 33 lb "truck" flywheel use different size clutches, the truck one is larger diameter- like 9mm

Madmax55 · #13 12-05-2016, 07:34 PM

Quote:

Originally Posted by panZZer

the 38 lb car flywheel and the 33 lb "truck" flywheel use different size clutches, the truck one is larger diameter- like 9mm

great information. SO If I was to rebalance my truck flywheel to match the MB one on the engine now I would be able to use my exact clutch?

panZZer · #14 12-05-2016, 08:13 PM

Quote:

Originally Posted by Madmax55

great information. SO If I was to rebalance my truck flywheel to match the MB one on the engine now I would be able to use my exact clutch?

I have no idea what flywheel you have-and I seriously doubt it, I was referring to the bens diesel TN truck / gwagen flywheel,

opk I reread your lat post,
the main thing to consider is the bolt pattern. how can you make your dodge FW go to the benz 12 bolt pattern.

the 4x4 labs kit has a chevy 6 bolt FW -which has had 1 or two welded up and redrilled so it can hit 6 of the 12 benz bolt holes.

panZZer · #15 12-05-2016, 08:24 PM

as far as ways people have been able to do this are,

a cstom adaptor plate between the original benz bellhousing and diesel FW to whatever manual transmission - like benzrover did in his old ehephant chaser and the GM sm465 4 speed,

a high dollar 4x4 labs kit that's just a thick aluminum plate / and a reworked chevy flywheel that replaces the rear benz motor plate like JB3 used in his astrovan.
and a cheap steel rear engine plate like Vladdo used in his jeep to bolt up the ax15 jeep 5 speed.

I was going to do a custom aluminum rear bell to bolt up many gearbox's but the nature of the benz crowd became very clear.
anyone contemplating doing custom parts for income --had better pick some crowd that actually understands the nature of prospering, ( that means people that design/make stuff have to make money at what they do).
Because if someone picks this crowd to make stuff for... he will soon end up living under a bridge someplace.