Hello all,

I have a 1980 300td with a 240d 4spd transmission and flywheel. I had the conversion done as I bought the car with a bad auto tranny. For the most part it runs GREAT. Fun to drive, no issues or vibration while in gear. The only problem is the shaking when at idle. I live in San Francisco so it is a lot of stop and go driving. I have to turn the idle knob way up to smooth things out at idle.

I recently found a euro 300td (4 spd.) at a junkyard and pulled the flywheel (heavier flywheel for 5-cyl.) I would like to install it and hopefully tame the 5 cylinder. I do NOT have the original automatic flywheel so no match balancing. If I bother with the swap I will have to neutral balance the flywheel and cut my losses in that department.

I am wondering how plug and play it would be to replace the smaller 240d flywheel with the bigger heavier 300td flywheel. I know I will probably have to replace the flywheel stretch to yield bolts, but will the bigger flywheel fit the 240d bellhousing without modification.


Any advice greatly appreciated.

Hans

P/S: Since I pulled the flywheel from the junkyard car I went ahead and bought the transmission. It was only 99 bucks so I figured what the heck. It seemed like 4th gear was 1:1. Is this necessarily the same as the 240d manual tranny. I would just as soon keep the manual tranny from the 240d as I know it is in good shape with pretty low miles. I don't know the condition of the 300td tranny.

I think you're gonna cause a lot of envy that someone found an OM617 manual flywheel in the US of A in a scrap yard. People on your side of the water pay a lot of dosh for manual flywheels.

The top gear ratio on all 4 speed gearboxes (fitted to Mercedes cars) are 1:1

The flywheel you have should be exactly the same diameter as the 240D flywheel - if it isn't then you've not got the correct flywheel.

If I were you I'd be looking for balance marks on the flywheel and the crank

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
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1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Wow. Sounds like there's no way that FW will work with your car. Better to just send it to me. I'll make sure it's well used somewhere.

But to answer some of your questions:

The FW is a bolt-in mod. You might want to have it refinished before installing it unless it looks really good already (but I hear refinishings are generally in $20-$30 neighborhood, so I would have it done either way).

Pretty much all MB 4-speeds had a first gear somewhere in the neighborhood of 3.90-3.98:1 and a top gear of 1:1.

BTW, you said you have an idle control knob? I though those only came with 240Ds. It would be fun to have one in my 300SD.

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1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."

The flywheel isn't your problem. If you are getting vibration at idle but not at speed, you need new engine and transmission mounts 75% of the time. Other shakes are caused by work injectors, valves that need to be adjusted, or poor injection timing.

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

That's what I meant to say but forgot! :slaps forehead:

Here are common causes for vibration:

Engine mounts
Engine shocks
Bad injectors (this would be accompanied by a "nailing" sound)
Valves that need adjusting

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"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."

i agree with S=B, address the problem more directly. i have the light manual flywheel on my 617 240D (in SF as well!) and not excessive idle shake.

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'77 240D, 504H, OM617.952, etc.

That all being said, I know a few guys who would be glad to buy that flywheel from you. *let loose the hounds!*

__________________
$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

Yes.

I have the light flywheel too. Vibration happens with the combination of high load and low engine speed. Around 1700 rpm in third and fourth gear is the worst. It doesn't do it in first or second. Idle is smooth.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.

The 38# flywheel will make the idle as smooth as a six cylinder. You also may need to put the idle speed higher.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Just FYI, they came on early non-turbo cars. My '79 300D has one.

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1979 300D 040 Black on Black - 1985 300D Maaco job (sadly sprayed over 199 Black Pearl Metallic) on Palamino

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Ok,

So the general consensus I get is to address motor mounts, valve adjustment, and engine shocks. At this point I don't want to mess with injectors too much if I don't have to. I have read mixed messages on the engine shocks. I have heard it suggested the shocks only dampen the engine during shut down.

I am interested in eventually swapping the bigger flywheel in. I am just a little concerned that the spacing somehow would not work out as the bigger flywheel is thicker (diameter is the same). I am just wondering what are the proverbial devils in the details of this job.

I am aware that my motor mounts are in kinda rough shape, actually pretty bad. I do not know the last time the car had a valve job.

Any additional input greatly appreciated

Thanks again,
Hans

I have one ready to ship here $350.00 plus shipping, can send greyhound

Can anybody recommend a good brand for the motor mounts and engine shocks. Obviously I don't want to go to the effort to install them and then they fail in 1 year. I was thinking febi bilstein. They seem pretty reasonably priced, but I heard their quality as a brand has been kind of sporadic lately.

Thanks again,
Hans

The flywheel isn't really thicker. the flywheel looks like a pie pan. the bottom of the pie pan is the same size between the 2 flywheels, but the dish is deeper on the 5cyl flywheel. i don't remember just how much deeper, but all the extra weight is on the side. Its kind of like the diffrence between Original and Pan pizza crust.... mmm I'm getting hungry.

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I just replaced the 240D FW for a 300D FW I found at PNP for $27.
There is nothing to modify, the 4-spd trans will slip right on.

I bought new FW bolts at the Monterey Dealer on their wholesale site for $5.80 each. Full retail is $7.25.

Mercedes Benz Parts at Wholesale - OEM Auto Parts


That was a good find in the yard. Just don`t see these FW all that often, I have only seen this one in the past 4 years.

Bolt it on your 300D and tell us how she runs.

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

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