I've got a '77 240D with just over 500,000 miles
The motor finally puked and I'm wanting to rebuild it. How can I get more power out of the motor? I understand it's not going to be a rocket, but I don't want to be trampled by these big 200HP idiots that are in a rush to get anywhere, ya know? Also, I understand there was a standard tranny as an option? Would it be worth it to swap one of those in?

I own a 78 240 D with a four speed manual. The car almost jumps to 45MPH. After that it takes a while to get to 65 or 70. But around town it is a great car. There are a lot of stop lights in my town, and it seems that none of them are timed. You end up stopping at each one, and I rarely have any one on my butt. It is usually the other way around because I always seem to be in a hurry. I have never drove the automatic but I was a passenger in one and it was a heck of a lot slower. So if you can find a manual tranny to put in your car I am sure you would like it.

It's not a simple project to swap to a manual transmission. There is a thread somewhere describing what would have to be done. A few things I remember would be:

1. Change the brake master cylinder reservoir to accept the clutch hydraulics.
2. Change the brake/clutch pedal mechanism.
3. Make sure you get all of the shift linkage and install a new center console plate (wood or plastic to accomodate shifter).
4. You'd also obviously need a tranny.
5. You'd need to verify that the drive shaft lengths are the same (not sure).

It seems like there is more, but this is all that comes to mind. It would not be a simple swap - you'd probably need a donor car to do it economically....otherwise, you'd be better off just buying a manual transmission car.

Good luck.

__________________
1976 240D
1987 560SL
2007 E320 Bluetec
1998 C280 (now son’s car)
1982 240D Manual - Sold

Swapping a manual for me is easy LOL! I restore and modify a bunch of stuff...but I don't know diesels very well at all!
I'd be willing to do the work to swap it to a manual. I'm assuming the manual trannies are rare...would one from a 300 D bolt up to the 4 cyl or are they a completely different animal.

But what about more power from the engine? I also have been thinking about swapping the 5cyl into there. I think it requires moving the motor mounts around. But I'd like to get more power out of the 4 cyl if I can.

(I grew up with this car and it's been handed down to me so I can't get rid of it....it's special )

Maybe I am just getting old and conservative, or maybe the 40 years of being interested in hot rodding causes me to say " Do not attempt to get more power out of the four cylinder " .

The reasons start with these.. 1. you can not increase the compression. 2. you can not turbocharge it without beefing up the critical parts.. or losing reliability. 3. You can not increase its breathing ability without screwing up the gas mileage.

Go to the 5 cyl... and the turbo if your really wanting more power... or transplant a gas engine into it...But even the 5 cyl with turbo does not have much power off the line,, the turbo kicks in and it flies low when it does... but the physics of it are such that is not the kind of feel which hot rodding a gas engine can give you. Greg

I have a 1980 240d with the manual 4 speed. It is very peppy, and I love it.

Swapping a manual usually is not a big deal... and you could even use an aftermarket hydraulic clutch mechanism I presume... but you may need to make provisions for making the pilot hole in the crank .. it seems that MB did not make generic cranks... but only put the holes for pilot bearings in engines which were scheduled to be have manual transmissions behind them...

If you do this,,,please take pictures and notes as you go so you can put up a FAQ page... many of us want to do this....(manual behind orig auto trans engine )... Thanks, Greg

77240D,

If your 240D engine is toast, why not just replace it with either a 300D or a 300TD. Put the manual transmission on either of them and you'll love the result.

1. You don't need to replace the brake master cylinder just cut the tube coming out of the side of the resevoir open so the hydralic clutch hose can fit onto the tank.
2. You'll need the tranny, shift mechanism from inside the car. Four small bolts and disconnect the linkage below and out it comes.
3. You'll need the linkage from under the car and shorten it exact four inches if you do the 300D thing. Keep the linkage in alingment as you reweld it after shortening.
4. Four bolts and a pin are all you need to remove the pedal assembly.
5. Make certain that you get the whole backup liight wiring pigtail when you get shift mechanism from inside the car. It unplugs next to the driver's side tunnel.
6. There are two different trannys that were used in this series of MBZs so you'll have to sort out the driveshaft length once the transmission is installed.
7. Driveshafts can be cut lengthened or shorten and rebalanced by local shops for around $125.00.
8. If you managed to find a driveshaft of the correct length, mark both ends so you can put it back together in in balance.

Goodluck! You'll love the results. We have a 240D, a 300D and two 300TD that we've put the 240D manual transmission into.
Ben

Ben, thanks for posting that.... I am pretty sure one day I am going to do that...

So you have not changed to the five speed when putting the 5 cylinders into the 240's ?

Was there any particular reason which might effect our decisions.. cost, availability, did not like the five speed, more hassels putting it in , etc ?

How much difference do you think it would make in mileage with the 5 speed ? Did you keep the axle ratios which came with the car when you did the swap ?

Thanks, Greg

Ridge:

What about the flywheel? In a recent post you mentioned the need to get a manual trans flywheel from either an earlier model 300D or from the W123 with manual trans. (Euro model since few if any were sold new in the US). I know the M-B manual says to only use the manual trans. flywheel for the manual trans. - the manual trans. flywheel is 90.0mm thick and the auto trans. flywheel is 76mm thick. What's up here?

Thanks,
Tom

__________________
America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.

Gentlemen,

The 5 speed will fit but finding one is the problem. Drove one in a 300D the other day and with the 3.46 rearend they're a little slower off the line than my 300 D G-wagen powered 240D but at highway speed in fifth you can certainly appreciate the stereo. Just whispers along. So in the end, one has to check out all the rearend ratios available to get the best off line acceleration and low RPM in fifth. If you're going to put a turbo in the 240, you definitely need a 3.07 turbo rearend otherwise you'' chirp" in every gear with the 3.46.

When I eventaully obtain some of the ones that I've tracked down and install, I'll let you know the results. The same holds true when we've finished prototyping the intercooler for my son's 300Turbo Diesel.

Ben

Right! Forgot about the flywheel. It's relatively difficult to find a 123 Series, 300D flywheel but there seem to be quite a few 115 Series 300D flywheels around. Five in oine yard that I know about.

Make cedrtain that when you're bolting the new flywheel on that you keeo the balance mark in line with the balance mark on the rear of the crank.

When I first did mine and was a total amateur, I drove around with a 110 flywheel on my car for about eigtheen months. What finally made me check it was that it just idled rough. Went like hell though.

Did you guys read my thread about the "MBZ Blood Frenzy" that we had out here. A MBZ repair shop was throwing away all their old non-runners. What a treasure trove. They're all at a local pick your part in Fremont California now.

Finally found an owners manual for my '77 240D/300D/G-Wagen. Finally found out about pulling the blue a/c knob out to route air to the back seat passengers. Amazing these Gremans!

Ben


Ben

I also have a 77 240d with 202,000 miles.

It uses a little oil between changes and smokes a little so I have thought of all the same alterations.

After looking at the cost of labor and parts etc. I realized that it would be much cheaper to just look for another car with a larger motor or standard transmissions. They are cheap compared to the costs involved in conversions. Could probably buy two replacement cars for the costs of fixing mine and I probably would be able to get a newer one in the process.

Swapping the manual trans for the auto trans will make a difference in acceleration and add a bit of speed on the top end. The local San Antone Pick and Pull had 2 240 W123 with manual trans a few months ago - don't know if they have the trans parts since I have not out there is several months. Look around your area junk yards to see what they have.

Not much you can do to make a 240 engine run better. That said, you're engine with 500,000 miles was probably pretty tired and a fresh rebuilt engine should be a lot better.

Swapping a 300D turbo or non-turbo engine for the 240D is more than doable. Engine mounts are in the same position, trans is a different but changing is easy.

Non-turbo engine is an easier swap. You will want the complete engine and driveshaft from the 300D non-turbo since the engine is longer by one cylinder - the auto trans are the same for the '77 240 and 300. Get the 300 radiator and oil cooler (greater capapcity), air cleaner, throttle linkage, vacuum lines/connections (should be same/similar - but grab'em anyway), etc., etc.

The turbo 300D engine will also fit, but you will want the entire drive line (complete engine and everything connected to it, trans, driveshaft, rear end because turbo has different gear ratio), then you're going to need the radiator, overflow tank, oil cooler, electrical harness and glow plug relay/elec connections, AC compressor (has the Frigidaire type) and AC lines, some/all exhaust system, air cleaner, throttle linkage, vacuum lines/connections for engine and trans, etc., etc. If you have the York AC compressor on the 240 then you will need to lengthen the AC line's rubber section or get the ones from the turbo 300. A couple of members have done the turbo engine swap and can add a lot more info than I can. I just know of the differences and what you need to get (everything from the donor turbo), but have not done the swap myself.

Take pics as you go and keep us informed!

Good Luck!
Tom

__________________
America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.

Ben ! Now you have done it ! That Blue knob was supposed to be a secret.. only disclosed after proper background checks are concluded....

Hmmm...sounds like the search is on for a donor car.

How much of a difference is there between the turbo 300 and the non turboed 300? Is it worth all that work (looks like you damned near have to rebuild the driveline for the turboed)?

Here is a pic btw (I'm proud of her ):