Manual Trans for 5 cyl 3.0 Turbo Diesel

[MB300se65]

Dear Benz Friends:

I'm building a frame-up 4X4 using the 617.952 engine bolted up to an NP 435 transmission and NP 205 transfer case. I've had an adapter fabricated using the 2.4 liter diesel bell housing, flywheel and clutch assembly that mates up perfectly, but I’ve been told I'm going run into some major issues with that flywheel, as the one in the 2.4 liter and 3.0 liter are balanced differently.

I hear a European Mercedes with a manual transmission was offered using this engine and I think one of these flywheels may be a partial solution. I understand I can’t I take a flywheel from another engine and interchange it without rebalancing the whole assembly as a unit, which I plan to do and want to know if someone can tell me what Mercedes this flywheel would come off of.

Thanks,

MB300SE65

[Ken300D]

I am sure we'd all like to see a picture of your custom adapter. And some details on the source and cost.

I believe what you need to look for is a European 300D without the turbo, and a manual transmission. That is going to have the better-matched flywheel to the 617 engine.

There are a few conversions described on here that you might search for.

Ken300D

Originally Posted by MB300se65

I understand I can’t I take a flywheel from another engine and interchange it without re balancing the whole assembly as a unit,

That is completely wrong. You do not have to balance the entire assembly, only the two flywheels. Get a manual flywheel, one from a 2.4 is perfectly fine, take it to a racing shop and ask them to match balance the new flywheel with the original flywheel. That's what I did and my engine has been running great with it for 1-1/2 years and 15,000miles.

[Mister Byrnzoil]

I'd love to see pics of the tranny adapter.

[michigandon]

I want to see this adapter also! I believe it's made by a friend of Jim Youngs.

Got an OM616 to T90 adapter in the works here myself!

[MB300se65]

Thanks for the input! I haven’t had a chance to get in here since I submitted the post and apologize for not responding earlier.

Lance, are you saying I should buy a flywheel for a European 300D with manual transmission and have my 240D flywheel balanced to match it?

If this is the case, I’m I to assume I’d return the new 300D flywheel after using it to get the balancing correct on the 240D one?

My engine is from a 300D automatic I’m converting to manual, so why wouldn’t I just use the new 300D flywheel and throw the 240D one?

Numerous people have told me I need to balance the entire crank assembly with the new flywheel. Is anybody knowledgeable on this?

The adapter to mate the 240D bell housing to the NP435 transmission was made by a friend of mine here in Oregon and is pretty slick.

I was shocked to find the input shaft on the NP435 was exactly the right length and the OD end fit the ID of the Mercedes pilot bearing perfectly.

The NP435 came out of a 1-ton Chevy and I didn’t need to make any changes to it even though it’s SAE and the Mercedes is metric.

I did however need to have a custom clutch plate made, as the splines on the input shaft didn’t match the female ones on the Mercedes.

To mount the engine in the 56’ Willys, I cut the cross member with motor mounts out of the Mercedes and welded it into the frame of the Willys.

It’s all currently mounted in the frame, but I should be able to get some pictures of the adapter sandwiched between the bell housing and tranny.

MB300se65

[TheDon]

no .. take the flywheel from the engine already and have the one from the 240D 4 speed engine match balanced to it

[winmutt]

Just my 2 cents. I took a 200D (which is probably same as 240D) fly wheel and stuck it on 617.952 without balancing or anything. No vibrations and revs quick. In 4x4 I would imagine you would want the heaviest flywheel possible.

[MB300se65]

I hate sounding stupid, but does the 5 cyl 3.0 Turbo Diesel have a flywheel when configured with an automatic. I do remember pulling the torque converter out and did unbolt something from the rear end of the crank that one might call a flywheel, but it was pretty anemic looking for a flywheel. Is this the piece I should match balance with my 240D flywheel? I’ll have to go through my old parts and dig it out. If this is the case, this should be a fairly easy fix.

Another item that may be a problem is the turbo and transmission interface. I understand when the turbo kicks in it somehow changes the fuel pump delivery volume using vacuum pressure off the Mercedes automatic transmission. If so, I'm going need to figure out how to accomplish this on a manual transmission that has no vacuum pressure. Does anybody know anything about this and what the potential fix is, or whether it’s even going to be an issue?

[junqueyardjim]

The torque converter acts as a flywheel on the automatics. The flimsy thing you thought or called the flywheel is actually the ring gear mounted on a spoked hub, usually of three spokes, to which the converter is mounted.

Right, the torque converter acts as the large majority of the flywheel weight in an automatic.

Numerous people have told me I need to balance the entire crank assembly with the new flywheel. Is anybody knowledgeable on this?

They are just being cautious. What you need to do is have the manual flywheel match balanced to the flywheel originally on your engine. Be 100% sure to mark your flywheel for #1 cylinder at top dead center before you remove it from your engine. The attached picture is what the automatic flywheel looks like. You don't need the flexplate or torque converter to balance the other flywheel.

The choice to use a manual flywheel from a 240 or 300 is up to you, it will run perfectly fine with either one. The heavier 300 flywheel will give you more torque off the line but the 240 flywheel will give you quicker acceleration.

Another item that may be a problem is the turbo and transmission interface. I understand when the turbo kicks in it somehow changes the fuel pump delivery volume using vacuum pressure off the Mercedes automatic transmission. If so, I'm going need to figure out how to accomplish this on a manual transmission that has no vacuum pressure. Does anybody know anything about this and what the potential fix is, or whether it’s even going to be an issue?

The turbo does not use any vacuum for fuel control, it uses boost pressure. One of the great things about having a manual transmission is the significantly more simple vacuum system.

[Willard]

Lance has it right.

a 240D flywheel is fine. Just get it balanced. and make sure you mark your old flywheel. Some are marked from the factory (mine was)
I am doing something similar to you expect i am putting this into a 74 Land Rover.
I got my flywheel off these forums at a very good price (it should be here next week). I had my adapter custom made by another Land Rover enthusiast.
You also may need to make a pilot bushing to go into the crankshaft hole as your tranny output shaft may be smaller than the MB auto. Mine is made from Brass.

Oh, speaking of the pilot bearing....

Late 1984 and 1985 617's have a smaller pilot bearing hole (About 0.080" smaller).

[winmutt]

Originally Posted by ForcedInduction

Oh, speaking of the pilot bearing....

Late 1984 and 1985 617's have a smaller pilot bearing hole (About 0.080" smaller).

Yes they sure do. I just ground down the bearing instead of the the crank.

[pitansk]

Originally Posted by Ken300D

I believe what you need to look for is a European 300D without the turbo, and a manual transmission. That is going to have the better-matched flywheel to the 617 engine.

Ken300D

i just happen to know someone with this car, a euro 617 non turbo with a manual 4 speed. the exterior and interior are flippin' atrocious. but it runs like a champ. my friend wants to unload it so PM me for details.