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5.0 HO/T5 swap into W123 Mercedes 240D

Old 04-21-2012, 04:47 PM
CID Vicious
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Default 5.0 HO/T5 swap into W123 Mercedes 240D

Hi all,

Tried finding out about this on the Mercedes boards but I mostly get a lot of 'eww, why not a Mercedes motor' or 'just leave it stock and buy a car that isn't what you want' or whatever.

I figured I might find some more enthusiasm over here.

I'm going 5.0 even though I'm a Chevy guy. My last ride was an LT1 powered Roadmaster, and I loved that motor. However, 5.0/T5 is cheap, easy, and happens to fit the chassis better. I'd love an LT1/T56 but so would half the hot rodding world. Even the RWD import crowd is waking up to American V8s.

Anyway, like I said, however, the 5.0 happens to be the right tool for the job, and while I never took that big of a shine to the Mustang itself, I can't say anything bad at all about the powertrain.

Likewise, I can't say much but good about the W123 body, chassis, suspension, build quality, etc. I live in LA and these cars go for peanuts, have great brakes and suspension and also have smog exemption.

So, if you know of anyone who has done this and posted a build thread somewhere, great.

If I have to suss it out myself I will. I'm currently looking at whether to use the cable setup from a Fox body clutch or whether I can setup a hydraulic clutch with the T5, since there's already a stick in the donor Merc. Er, Mercedes, not Mercury .

I've done a lot of driveline homework on this car already, and this is almost a poor man's IRS quick-change. 240D's rear ratio is 3.69:1, can swap pumpkins from Benz cars going down to low 2's. Real easy, drop pumpkin/axles...

Anyway, let me know. Thanks.
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Old 04-21-2012, 09:34 PM
Bubba 95SN
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Mc Leod makes a hydraulic kit $579 at LRS(Late Model Restoration Supply)
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Old 04-21-2012, 10:23 PM
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Originally Posted by CID Vicious View Post

I figured I might find some more enthusiasm over here.
doubt it, most are purists here
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Old 04-27-2012, 06:36 PM
CID Vicious
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Well, I don't need everyone's help - just a few.

Personally, I don't see much difference between swapping a 5.0l into a W123 and swapping one into, say, a 65 Mustang. Neither swap is for everyone - there are folks with a variety of opinions on such a thing. That's fine with me.

Personally, I like the car. The 'bank vault' doors. The chassis and parts interchangability, and the local availability - I live in LA, where such cars are turned in for a new model when the ashtray gets full, so to speak. The W123 is the Mercedes equivalent of the Mustang in a sense, and in a sense the original Beetle. It's their most successful, best selling model. Parts are literally available anywhere you can drive a car, because these cars likely there and have been for decades.

For a time in Morocco, for instance, it was said that half the cars on the road were standard, four speed, 240Ds. They're a desert taxi. They're also a rally winning chassis. There's a W123 that has 2.4 million documented miles on it in the Mercedes factory museum. It's former occupation? A taxi - in Budapest. Went through 4 OM616 motors and a few transmissions and was 'mothballed' before it had a chance to be wrecked. For awhile it was the world record holder for most documented miles on a single chassis.

Plus, if you squint, it's just an amalgamation of 'old car'. I like the 'old ness' of the outside sheetmetal, grille, chrome bumpers, etc.

And I like the 'newness' of the chassis. It has a vaguely 'American' steering feel but a very good version of it. I've driven a lot of cars that are handling benchmarks, Porsche 944s, various Hondas, SE-Rs, MR2s, BMWs, and a supercharged Fox or two. The chassis is very good, the parts are standard, so I can drive it anywhere, and the powertrain is one of the easiest to maintain on this continent - should I go 5.0, that is.

The car is already lowered, flat black, very 'hot rod' looking. I'm going to redo the suspension but this is very easy - the front springs are 14 coils, the rear 11, and if you look at the stock 240D/300D/300TD/300CD cars, they're set up like 4x4s almost. Baloney tires on soft, long travel springs with lots of ground clearance.

However with so much leeway, in one of the only instances I've seen where it makes sense, it's just so easy to get a fairly ideal setup (for nearly free, it is perfect - as much as you'll get for the investment) by chopping a few coils off the front a couple off the rear.

As for how the V8 would change the weight of the car, it would actually probably lighten it. The OM616 is roughly the weight of a small block Chevy - the OM617a, the turbo, roughly that of an old school 'iron everything' big block. The 5.0l is lighter than either of these motors so handling characteristics will only improve or stay the same.

I've done extensive 'research' in the canyons around Los Angeles with this chassis, and that was with a sunroof and AC, neither of which this car is burdened with. The Mercedes 5 lug pattern and various generation to generation compatibilities mean I can keep the 14x6 'steelie look' aluminum rims that came stock on the car with the widest/grippiest tires I can find all the way to what I really want on the car, which are the 17" "Torque Thrust" looking wheels that came stock on late model C230s and such.

The small block Ford was a popular swap into earlier Mercedes chassis because they happened to fit very will with either the front or 'mid' sump oil pans and the transmissions basically go the right place on the crossmember.

The W123 chassis was actually designed to accept a Mercedes V8 M117 series engine, but only with an automatic transmission, and frankly, I'd rather put a 5.0/AOD in there rather than a MB trans. They're programmed to upshift early out of 1st gear into second and there's no getting around it that I've seen. Manual transmissions of any sort behind a Benz V8 is $$$$$ and the MB manuals kinda suck really. Even to recent models, nothing to write home about other than the fact that a Benz is rolling with three pedals at all.

I'm also taking into consideration that my Mercedes in any build condition is less of a target for cops than any Mustang in any build condition. Mustangs, Camaros, Civics of any sort, etc, get looked at hard by cops. I immediately missed my lowered, maroon with blacked out trim 240D's seeming invisibility on the LA highways.

With only a hint of sarcasm I say it's probably something about a caucasian weirdo speeding around in a vintage Benz that probably makes the cops say 'next!' in LA. Who knows who I might be the nephew of, or whatever.

I'll take it where I can get it.

Plus, it's just a practical car. The parts are still around and cheap. It's four doors with a decent back seat and a good sized trunk. Safe - not like, say, V8'ing a Datsun Z car, which are mostly made of tinfoil.

Due to the design of the rear, I can undo 10 bolts or less and drop the pumpkin and axles. Translation - drive X miles to race with granny gears (high as I want, to 2.20:1) for mileage, Swap in welded 3.69:1 240D gears/axles, compete, swap again, drive home. I've seen folks on the Benz boards report high 20s with a mild 5.0 and a T5 with the Benz V8 gears.

Personally I see swaps like this as a natural progression of 'hot rodding' as the chassis become cheaper and cheaper and the 'native' drivetrains that came with them become harder to maintain/more valuable, aka more worth seling than modding. Google V8 RX7 Forums, 'Where To Go When Your Rotary Blows'. I think you'd like the company.

Even the pushrod hatin' import mags have been warming up to the fact that American V8s simply put out more hp/dollar than can be had, reliably, from a lot of the overseas motors, with less hassle. It's hardly any harder to put a 5.0 in a W123 or RX7 than it is in an OG Mustang from the sixties, and if you're going to romp on the car, why pick such a valuable chassis?

For me, most of the 'engineering' has been done. I'm aware of the various suspension kits to make a Fox slalom like a Viper GTS and all of that, but for 2500 bucks or so that they cost I can have this car done.
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Old 05-02-2012, 07:32 AM
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I don't have any tips, other than GO FOR IT! I love and always wanted one of the old Mercedes sedans; it is still on my car bucket list. Dropping a 5.0 in it? Yeah, that makes sense too. Of course, I am from L.A. too so I understand.
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Old 05-03-2012, 09:36 PM
CID Vicious
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Originally Posted by SteveDwsn View Post
I don't have any tips, other than GO FOR IT! I love and always wanted one of the old Mercedes sedans; it is still on my car bucket list. Dropping a 5.0 in it? Yeah, that makes sense too. Of course, I am from L.A. too so I understand.
Appreciate it, man. I should probably seek out a 'hybrids' site - think, not Prius - as I'd be more likely to find the enthusiasm and knowledge base I'm looking for. I'd have to admit, I'd be a little protective if I thought of someone taking a car I dig - say, the 94 Roadmaster I sold to get this Benz - and more or less saying they're gutting the drivetrain. I get the reaction.

The Benz guys are no different, really. Eww, a lighter, more powerful, easier to maintain and completely buildable drivetrain that isn't a Mercedes. What WILL the neighbors think . There's a few 'go for it!' guys over there, too, and a few that have done the swap. I just haven't found a build thread yet.

I might even try the Volksrodders forum - those guys love two things - whacky rat rod style projects, and welding. I love referring people to that forum when they come from a 'if it doesn't bolt on, it can't be done' mentality . The only problem is that the project might be a little blase for them, but hey, what can you do.

If I do this I'll likely do a whole how-to. The cars are cool done up right, they just look dowdy and 'grandpa' as all hell stock, and most people don't mod them.

Here's my old 240D right before I sold it. So little to do to achieve this, it's almost criminal. Just add motor and admit, you're thinking - 'I'd hit it - like the fist of an angry god!'

Little 'photoshop phantom' work here. Makes you wonder where they got the idea for the nose for the previous gen Charger, doesn't it?

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Old 04-23-2013, 04:10 PM
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Default V8 Mercedes 240D

Just saw the posting on the 240D MBZ 5.0/T5 swap. I'm going to be doing the same with my 300D/Turbodiesel, getting the motor pieces together first, and will be running a AOD with it. I bought a motor kit from "Woody" at, a 347 stroker with Trick Flow 192 heads. I had a custom Hi-lift, low duration cam ground through fordstrikers also. I'm looking for a relatively smooth idle, (so my wife can drive it too...) and some serious torque.
The MBZ 123-chassis is their most successful, and longest lasting vehicle on the road. It may lean a little bit around the turns, but it feels like it's on rails giving you the confidence entering a hard turn. The suspension smooths out the road very well, and parts are always available. The one I bought had the engine seize when it ran out of oil-great body and interior-I'll give that motor away. I also picked up a mock-up 302 plastic long-block, and AOD to use to design/build the mounts, and see how the exhaust is going to run.
I should have the mock-up started by end of May, I'll keep posting as I move along. I do drive a 1992 5.0 GT Convertible, still loving every minute.
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Old 04-23-2013, 05:46 PM
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Purists!! HA!!! Not around my place!


-DO IT!!!

-Since you're clearly down for some fab work, skip the McCleod kit and look at S10/F-Body (and even AMC) hydraulic clutches. The T-5 on my AMC Eagle uses an external slave... I've often considered fabbing a mount up to make it work on a Fox bell housing... then I thought about how that won't make the car the least bit faster and moved on. Not quite the same boat you're in.

-Get a 5.0HO out of a more "modern" Fox. MAF motor is preferred

-Now to contradict myself, I'd get it running with a carb first just for simplicity's sake. Sort out the EFI later or never. Your call on that one.

-You're going to need some real tires

-It's going to need lowered at least 2"

-Body color bumpers, grill, trim, and clear fogs
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Old 04-23-2013, 07:43 PM
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Do it.
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Old 04-24-2013, 10:44 AM
MBZ 347 Stroker
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Default The 347 swap

I'm using the AOD due to torque considerations, I thought about the T5, but don't want the drive train to scatter bangin' gears. I'll leave that to my '92 GT, I want the MBZ to be a sleeper, and appear as stock as possible.I'm going to also run the Powerjection-III fuel injection, but plan to start it with a carb and simple ignition. I'm looking for a little over 400 ft-lbs torque, and an honest 375hp. I don't think the center support bearing assy. on the original driveshaft will handle the power very long with a stick, and I'll just invite the law rowing through the gears...I would also like to see others that have done the swap, I've only seen a 450slc with an LT-1, what a hassle that swap was. I also want to find a good match for a MBZ air filter box to help it look more original.
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