Non MB trans to MB engines - Page 37 - PeachParts Mercedes-Benz Forum

rwd4evr · #**541** 08-29-2019, 01:47 AM

For real. Crazy it's been going this long. I still don't get why everyone is obsessed with the 3.5 ring gear. Get an auto ring gear. done. If your putting it behind an alloy block engine the 3.5 ring gear is useless unless you adapt an iron block bellhousing to it. They are different sizes and the starter won't line up. Get an e36 flywheel, egg the holes a touch, bore the center to be correct for the crank and bolt the auto flex plate behind it. Done. If I didn't have a 4 speed or two already I would have made it happen.

cth350 · #**542** 08-29-2019, 10:38 AM

It depends on perspective.

We're like Edison. We know lots of ways how not to adapt a standard trans to a Mercedes engine.

Actually, the cool thing about this thread is the number of people that have contributed what they have done to tackle the problem their way. Not all of us have done it, but some have.

-CTH
PS. The thread turns 10 in February, so it's only been 9.5 years.

97 SL320 · #**543** 08-29-2019, 07:02 PM

The Dodge Neon and Chrysler PT Cruiser with a manual trans use an auto trans flex plate then bolt up a flywheel / pressure plate just like a torque converter. 70's / 80's VW Rabbit did something similar with the pressure plate bolted to the crank then flywheel facing the transmission. I would have thought this would be too flexy but apparently it works.

Part of the problem with the M104 is the crank flange sits below the bell housing flange and the bell housing pattern is pretty small limiting clutch diameter to 9" or so. The small diameter could be solved with a double disc setup but that is $$. I haven't come up with any non MB 8 bolt FW that has the same bolt circle of the M104 either.

I'm now thinking:

Make a road wheel type adapter between the crank and flywheel. This accomplishes a pattern change and spaces the FW out past the BH flange / adapter. I'd want to place the auto flex plate against the crank to use as a starter ring gear and then pin everything together so the bolts are not working is single shear so much. I'd also make stands that bolt from the flywheel to flex plate to reduce flex plate vibration and help take torsional load off the flywheel to adapter bolts

Use a more common bell housing ( steel scatter shield ) that matches the flywheel / clutch. This allows for an off the shelf transmission even an aftermarket.

The down side of this is we are spacing a heavy rotating object out from the last main bearing pretty far and this could be a crank breaker long term.

rwd4evr · #**544** 08-29-2019, 07:13 PM

Yes the spacer is already done with jeep om617 and 603 conversions. The bolts in shear is a non issue, the clamping pressure takes most of that out of the game, unless it works loose it's fine. I have that adapter, the Jeep flywheel bolts to the adapter which you use as a drill guide for the Mercedes pattern, then you bolt through the whole assembly. I'll be using a centering transfer punch then drill it on my drill press though. This one uses the jeep starter on the adapter plate which replaces the alloy block plate on the om617 but using the auto flex plate and ring gear with original starter is an option in a conversion like this . The nice thing about that type of setup is that you set the pilot bearing/bushing in the adapter and a shorter input shaft isn't an issue. You just adjust thickness of the bell and crank spacers to suit it.

rwd4evr · #**545** 08-29-2019, 07:20 PM

Quote:

Originally Posted by cth350

It depends on perspective.

We're like Edison. We know lots of ways how not to adapt a standard trans to a Mercedes engine.

Actually, the cool thing about this thread is the number of people that have contributed what they have done to tackle the problem their way. Not all of us have done it, but some have.

-CTH
PS. The thread turns 10 in February, so it's only been 9.5 years.

Yeah sometimes you need that little push in the right direction to get that " oh duh, why didn't I think of that" moment to get past a problem.

VaiFanatic · #**546** 08-30-2019, 12:47 PM

Quote:

Originally Posted by rwd4evr

Yeah sometimes you need that little push in the right direction to get that " oh duh, why didn't I think of that" moment to get past a problem.

This is where I'm at. I'm glad my stirring got some more info.

I'd not considered the E36 flywheel, plentiful around here in the yards if I didn't choose to go brand new.

rwd4evr · #**547** 08-30-2019, 04:40 PM

Quote:

Originally Posted by VaiFanatic

This is where I'm at. I'm glad my stirring got some more info.

I'd not considered the E36 flywheel, plentiful around here in the yards if I didn't choose to go brand new.

Most in the yard would be dual mass. You really want a conversion flywheel. Also, only(I think) 96 and up 328 (or m3) have the 240mm Clutch. Rock Auto will show what you need to figure that out. A mustang 8 bolt modular is an option too. It's tight with a 10.5 clutch though. There's info in this thread back a ways.

VaiFanatic · #**548** 08-31-2019, 01:03 AM

Quote:

Originally Posted by rwd4evr

Most in the yard would be dual mass. You really want a conversion flywheel. Also, only(I think) 96 and up 328 (or m3) have the 240mm Clutch. Rock Auto will show what you need to figure that out. A mustang 8 bolt modular is an option too. It's tight with a 10.5 clutch though. There's info in this thread back a ways.

I'm definitely not about that dual mass flywheel life... I do have the info for the modular flywheel, and I've kept it just in case I choose to go that route.

Sometimes I get to thinking about what's needed to be done, and part of me is like "hmm, maybe just a domestic motor is a better choice..."

I'm buy no means loyal the M117, as great of a motor as it is, and I don't care for being a purist either. Would I like to keep it MB? Of course, but to get the driving experience I really want, I'll do whatever to get there.

Like that LS1 we stuffed into an '85 RX-7 with a TKO 500.

rwd4evr · #**549** 09-02-2019, 01:55 AM

Quote:

Originally Posted by VaiFanatic

I'm definitely not about that dual mass flywheel life... I do have the info for the modular flywheel, and I've kept it just in case I choose to go that route.

Sometimes I get to thinking about what's needed to be done, and part of me is like "hmm, maybe just a domestic motor is a better choice..."

I'm buy no means loyal the M117, as great of a motor as it is, and I don't care for being a purist either. Would I like to keep it MB? Of course, but to get the driving experience I really want, I'll do whatever to get there.

Like that LS1 we stuffed into an '85 RX-7 with a TKO 500.

Funny you mention a first gen RX-7. One of my favorite cars I've owned. I had a 85 gsl fb in my teens. I just went and test drove a 80 sa (super rare 12a turbo cars too) with a 302 and t5 in it. Tried to trade it for my 300sd but he got cash the next day😭☹️

OM616 · #**550** 09-05-2019, 05:00 PM

Quote:

Originally Posted by cth350

It depends on perspective.

We're like Edison. We know lots of ways how not to adapt a standard trans to a Mercedes engine.

Actually, the cool thing about this thread is the number of people that have contributed what they have done to tackle the problem their way. Not all of us have done it, but some have.

-CTH
PS. The thread turns 10 in February, so it's only been 9.5 years.

X2

The hang up on my end has been the custom flywheel cost.. I can't make one for less then 1K each which has been a road block.

A while ago I figured out a way to make a modified off the shelf aftermarket flywheel and Ring Gear/Crank Trigger ring combination work for the 420-G set up. There still is a lot of work in it to make it work, but it is less extreme then making a custom billet flywheel, and this approach is much more accepting custom setups like the M117/M119 to 420-G set up.

VaiFanatic · #**551** 09-13-2019, 08:09 PM

Quote:

Originally Posted by rwd4evr

Funny you mention a first gen RX-7. One of my favorite cars I've owned. I had a 85 gsl fb in my teens. I just went and test drove a 80 sa (super rare 12a turbo cars too) with a 302 and t5 in it. Tried to trade it for my 300sd but he got cash the next day😭☹️

Yeah, they have a certain charm to them, and are arguably my favorite body style for the RX-7.

The 13b motor and trans is rolling around the shop, wondering what to do with it. It is now mine to do with as I want. Don't have anything to stuff it in myself currently.

It was a motor that was turbocharged by my buddy way back in the day and ended up with us again some time ago for more work. It took the owner a few years before he decided he wanted to have us pull the rotary and stuff a V8 in there; we got started pretty quick when we did.

rwd4evr · #**552** 09-15-2019, 02:35 AM

Donate it to me. I'll put it in my 64 190c.

VaiFanatic · #**553** 09-17-2019, 12:34 PM

Quote:

Originally Posted by rwd4evr

Donate it to me. I'll put it in my 64 190c.

I would if I could help with the build and drive it whenever I wanted to...

I've been doing a lot of thinking, and it seems the best bet when it comes to not need to make parts come service time for the transmission, is to simply use a motor and gearbox combo that already exists. In other words, move away from the MB motor entirely.

It's far easier for me to fabricate a way to secure the motor, and modify or custom-build an oil pan for a different motor. Cost will be more for a motor swap, and certainly more time consuming, but replacement parts will be plentiful and easy to source depending on what platform you choose.

I'm not loyal to the M117, and I don't care about resale value or collectibility of a car I never plan to part with anyway.

rwd4evr · #**554** 09-17-2019, 07:52 PM

Quote:

Originally Posted by VaiFanatic

I would if I could help with the build and drive it whenever I wanted to...

I've been doing a lot of thinking, and it seems the best bet when it comes to not need to make parts come service time for the transmission, is to simply use a motor and gearbox combo that already exists. In other words, move away from the MB motor entirely.

It's far easier for me to fabricate a way to secure the motor, and modify or custom-build an oil pan for a different motor. Cost will be more for a motor swap, and certainly more time consuming, but replacement parts will be plentiful and easy to source depending on what platform you choose.

I'm not loyal to the M117, and I don't care about resale value or collectibility of a car I never plan to part with anyway.

Yeah but getting an LS or whatever to fit with exhaust, power steering, electrical, gauges, and that's after motor mounts and oil pan is not just Abra cadabra. Trust me I've been back and forth with that a million times. There is something to be said about doing it with the MB powerplant.

VaiFanatic · #**555** 09-17-2019, 11:21 PM

Quote:

Originally Posted by rwd4evr

Yeah but getting an LS or whatever to fit with exhaust, power steering, electrical, gauges, and that's after motor mounts and oil pan is not just Abra cadabra. Trust me I've been back and forth with that a million times. There is something to be said about doing it with the MB powerplant.

Well aware it ain't magic or done in three easy steps. It certainly wouldn't be my first time stuffing something that didn't belong into something that it shouldn't be in.

I took care of the electrical in the RX-7 without much of an issue; we have someone who build harnesses who made us one for cheap, so it was relatively plug and play. AC took some fiddling, but that works once more. Speedo is cable driven, and the TKO500 allows the use of a cable. Haven't addressed the tach yet, but I guess we'll just throw the rotary back in if that proves too troublesome.

If I HAD to keep it MB, I would consider the M119 as a direct swap, that has been done before by a handful of folks. That still leaves me designing and engineering a manual transmission solution. Early M119s are CIS-E, so there wouldn't be much of a wiring headache.

The key is, what ultimately makes the most sense to get me the driving experience I'm looking for. The carb'd M110 280S was a lot of fun, but lacked the on-demand power of a V8. So, from personal experience driving a short wheelbase 126 with a 4-speed, it was a lot of fun for me, and just made me feel in more control when I needed to downshift or do whatever I needed to do in any given scenario. I didn't go anywhere quick with only 2.8L moving a heavy sedan, but it felt more lively to drive than my V8 car with an auto that doesn't seem to like being in 1st half the time. European spec vehicles tended to come with first gear start, but if they did, no one told mine.

My automatic is in need of either a rebuild, or a replacement. I've already addressed the vacuum modulator, adjusted the vacuum accordingly, checked the bowden cable, kept up with filter changes, etc. If I'm going to spend any more money on the drivetrain, it will be toward finally swapping in a manual, or moving to a different drivetrain altogether.

I've given it an incredible amount of thought, and continue to do so. I still haven't quite determined where my time and efforts will be best spent. I'm not afraid of the prospect of more work, but it's not an easy decision either way. I've had the car for nearly 10 years, and have enjoyed the hell out of it. I can't imagine life without it, but I can't go another 10 years with it the way it is.

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