w115 300d 4-speed manual swap - PeachParts Mercedes-Benz Forum

54dan · #1 04-29-2013, 10:45 PM

So, I had such a great time putting a manual 4-speed in my 1985 300TD:

300d 4-speed swap: are you happy with it?

...that I decided it would be fun to do the same to my 1976 w115 300d NA. A WTB post on the classifieds here and several members came to my aid. Next thing I know, I have a big pile of all the major parts, see attached picture.

I have already pulled the auto trans out ... Next I'll temporarily install the 4-speed, measure to centerline of the driveshaft carrier from the flex disc and send that and the driveshaft off to the driveshaft shop.

Looks like one of the two crossmembers will work (the greazy one came out of the car) as the holes are long and slotted on both the chassis and the crossmember, eg, you can move it wherever you like, as long as the crossmember is long or short enough.

Pedal assembly is similar to w123 but very different in the details/pedal position. Shifter and linkages looks the same as the w123.

Won't really be able to get the project rolling for a week, but wanted to share and thought y'all would enjoy. Any thoughts appreciated as always.

-Dan

sassparilla_kid · #2 04-30-2013, 12:32 AM

Is that a 38lb 617 flywheel or is it the smaller 28lb 616 one?

54dan · #3 04-30-2013, 05:56 AM

Quote:

Originally Posted by sassparilla_kid

Is that a 38lb 617 flywheel or is it the smaller 28lb 616 one?

Alas it's a 240 28 lb flywheel. I'm very happy with the 240 flywheel in my 300TD -- I can't tell the difference between how it runs now with the 28 lb 240 flywheel and how it ran with the old automatic gear and torque converter.

Figure that I'll do these things with the 240 flywheels and whenever I stumble upon a 38 pounder, swap one out -- will be interesting to see the difference.

-Dan

junqueyardjim · #4 04-30-2013, 12:32 PM

Good answer on that flywheel. My conversion used the 240D flywheel also, took the short route, no balance, just put it on with new streach bolts for the flywheel. Balance is perfect, acceleration is great and being a long time HD truck driver I thought perhaps shifting would not be as good, but it also is perfect. I do get a bit of body vibes from the power pulses at low rpm and possibly that could be reduced with the heavy flywheel. But it is better all the way to keep those rpm's up a little and I don't think it hurts fuel mileage either.

1911diesel · #5 04-30-2013, 01:26 PM

man i want a 4 speed in one of mine. keep up the good work guys! maybe one day ill join the ranks of the 4spd merc drivers. i had one in an old 240 4cyl but i didnt think it keep it at the time. still kicking myself.

JB3 · #6 04-30-2013, 07:00 PM

one thing you will definitely enjoy over the 123 chassis, is the way the 115 chassis has a sliding slot for the transmission mount, way easier to mount basically anything, and always makes me wonder why they did away with that setup.

Other than that and the different pedal assembly, the cars will appear identical underneath. That was my impression. Look forward to updates! you have the bug.

54dan · #7 05-23-2013, 03:36 PM

Very happy with the conversion so far. It is interesting that this conversion only needs 2 1/4 inches of shortening on the shift rods -- I suppose that the w115 engine must sit a little farther back than in the w123 chassis.

Progress so far:

* Manual transmission temporarily installed to engine in order to take measurements:
* Shift rods shortened 2 and 1/4 inches.
* Drive shaft, from rear of flex plate to Cl of center bearing mounting holes is 22 and 5/16 inches.

* Driveshaft sent to be shortened, balanced, repaired as necessary
* Flywheel/pressure plate sent to be checked & neutral balanced
* Pedal cluster installed. Slightly easier than in the w123. One bolt is right up under the instrument cluster. Easy to get to after you pop out the instrument cluster.
* Shifter installed, identical to w123 as far as I can tell.
* Speedo cable installed. The one that was in it would have worked but the shorter cable from the 240 is a nicer fit.
* All new parts ordered from Pelican: Throwout bearing, pilot bearing, shift rod bushings, master cyl, slave cyl, linkage clips, flywheel bolts (ouch).

Looks like I'll get everything but the flywheel bolts before the weekend, but I am getting to the point where all this stuff "just bolts together" and the car is, magically, a manual transmission car.

-Dan

katja · #8 05-23-2013, 03:58 PM

Looking forward to seeing more details. I find it interesting that I've seen plenty of W123 Euros but I've never seen a Euro W115 240D 3.0 in North America. In Europe, I never saw one with an automatic transmission!

54dan · #9 06-10-2013, 08:08 AM

Got everything all buttoned up and the '76 w115 300d rolled out of the shop under its own power via direct non-fluid drive! She really is a joy to drive like this ... peppier off the low-end than the 300TD turbo 4-speed swap I did earlier, and with the ponderous, smooth elegance that seems to be the pre-w123 Benz.

Anyways -- no real surprises on this job. The pilot bearing did not feel tight enough in the crankshaft (which was a change from my previous experience with the '85 TD!), so I used some of the loctite green sleeve retainer.

Attached are a few pics ... first is the 240d crossmember installed temporarily -- note the slots in both the chassis mount and the crossmember. You loosen the bolts and slide things wherever you want; very nice. Next, I wound up welding together pieces of the exhaust supports from the auto and manual setups in order to get things to work out correctly (the 240d support wound up exactly at the downpipe junction. Next is the nearly-complete install, and finally the interior shot.

As always, many thanks to this great group for all of your help and encouragement. Thanks also to socalbenz for the transmission, associated parts, and extraordinary effort in shipping all the way from CA, and thanks to DeliveryValve for the very nice flywheel and clutch!

Let me know if there are other details I may have omitted that would be helpful.

-Dan

curtludwig · #10 06-10-2013, 10:58 AM

I've been told that a manual trans really wakes up the NA 617 and makes it a nice driver.

I'm super jealous, someday I'd like to have a setup like yours. A friend had a basket case '76 I probably could have had free but my wife would have killed me...

DeliveryValve · #11 06-10-2013, 06:16 PM

Great job Dan! How much off neutral balance was the flywheel and clutch assembly?

katja · #12 06-10-2013, 11:04 PM

Looks great! The torque you get starting off in first gear is so much fun....I couldn't imagine having an automatic. The only thing left to make it perfect would be a 5th gear and a turbo

Interesting about the exhaust downpipe location....I never would have thought of that, but it makes sense because the 300D is a longer block.

54dan · #13 06-11-2013, 07:05 AM

Hey DeliveryValve,

It wasn't off by much ... I asked the machinist and he showed me where he hit the flywheel with what looked like a 1/2" drill, maybe 3/16" deep twice in the same spot. He added a couple of weld beads on the pressure plate in a different spot.

In re-reading my post, I'm seeing that I did leave off the part about bleeding that blessed hydraulic clutch ...

...I wound up using the right-front caliper to the slave cylinder trick. It was pretty much the same as on the 300TD: several mishaps with the hose popping off, brake fluid everywhere, slippery shoes, swearing that I would just go buy a real power bleeder for crying out loud, and then, apparently by the grace of the heavens, the clutch just worked. Good times.

-Dan

whunter · #14 09-01-2013, 12:08 AM

because I am doing a conversion now.

1985 300D automatic to manual transmission, using 220D (vin# 11511010041125) parts.

.

54dan · #15 11-21-2013, 02:12 PM

Hey all,

I've decided to thin out the fleet and have decided that this 1976 w115 300d (now with 4-speed swap) needs a new home.

Non-turbo motor starts and runs well, although it has always had some blowby as long as I've had it. No significant oil usage. 4-speed swap was done with new minor parts (master, slave, hoses, flywheel bolts, etc) and the driveshaft was professionally shortened, repaired, and balanced. I replaced the engine mounts at significant expense a couple years ago (these are only available from MB), which made all engine vibration disappear in the car. The non-turbo 5-cylinder with manual trans is actually pretty fun to drive, and is snappy off the line.

There is some rust in the rear floorboards. I never considered it serious enough to do anything about. Body is faded powder blue. Decent tires, should be OK to drive anywhere.

I'll get it and some pics up in classifieds soon, but thought I'd mention it here in hopes of finding a good home with a DD regular who might have followed the swap. E-mail if interested. Asking $2800.

-Dan