W123 OM648 Project - Page 3 - PeachParts Mercedes-Benz Forum

BirthdayBenz · #1 03-19-2022, 08:16 AM

I've been planning and running new electrical things.

I ran the positive battery cable salvaged from the W211 from the trunk. I ended up doing this twice. First I went up over the rear fender following the vacuum lines but then when I made it to the firewall I wasn't happy with the length. I removed the cable and re routed it by drilling a hole next to the passenger side strut. It now routes around the fuel tank and I've got an extra 2ft or so of cable to work with.

Bonus! I found an old mouse nest behind the fuel tank and vacuumed that out.

I used the power distribution block from the W211. Mounting it in the passenger kick panel. I've still got some reinforcement/better mounting to do as the angels in the W123 floor area are not the same as the W211. Nothing is fully bolted down in the final position in any of these photos.

The red cable on the distribution block is wired to the W123 main power wires that were originally directly connected to the battery. This will provide power to all the original systems in the vehicle.

Engine side of firewall

ECU Mounting:
The ECU will be mounted on the old battery tray. I found and modified a waterproof camera case.

Engine photo for no reason. That turbo looks large...

I ordered the wrong throwout bearing and wrong clutch alignment tool. So I need to find the correct ones and reorder. This is why the engine is still on the stand and not assembled to the transmission.

BirthdayBenz · #2 03-23-2022, 08:09 AM

I had mounted the adapter plate and flywheel but I'm experiencing some clearance issues between the automatic flywheel portion and adapter plate.

Looking good:

But the adapter plate contacts the automatic flywheel ever so slightly.

The new flywheel bolts on top of the automatic flywheel in order to retain use of the crank position sensor pickup and ring gear.

I had not removed the automatic flywheel when first installing the new manual flywheel and adapter plate, but ended up doing so while troubleshooting the clearance issue. What I found between the automatic flywheel and crank was a spacer.

I removed that spacer and reinstalled the flywheel and have just the right amount of clearance between the flywheel and adapter plate. I still however heard metal to metal contact when rotating the assembly. Again, everything came apart and this time I found some witness marks on the OM606 oil pan.

I'm out of time this morning but I think if I remove some material from the witness mark area on the OM606 oil pan everything will fit.

I reached out to DiselpumpUK to verify the installation procedure as I have no documentation. I'm just interested in confirming if the spacer is typically removed.

BirthdayBenz · #3 03-25-2022, 06:49 AM

Removed some material from the OM606 oil pan. Flywheel on and off about 3 times to get it just right. Everything is assembled and torqued no rubbing.

Hopefully the correct BMW parts for the transmission will arrive today. Those would be TOB, Clutch fork, retainer spring, and clutch fork pivot mount. I'm camping this weekend so wont be able to do any more work until next week.

BirthdayBenz · #4 03-28-2022, 08:14 AM

A couple simple modifications to the bell housing of the GS6-37DZ were needed to fit it to the adapter plate. I put the transmission on and off about 4 times. This is not something I'd want to do if the engine was already installed in the car. The Transmission weighs about 130lbs.

The first modification was removing a bit of material around the starter. The end of the starter poked out past the adapter plate about 10mm and was contacting the transmission bell housing. The second was that the bolts supplied with the adapter plate kit would not fit through all of the holes in the transmission. Luckily aluminum is easily drilled out.

Holes on transmission marked for drilling:

Transmission attached. Note starter area where material was removed:

The whole thing weighs in at 676lbs.

The next step is going to be attempting to shoehorn this beast into the W123.

BirthdayBenz · #5 03-29-2022, 03:49 PM

I have H&R springs in my car and had a concern that I might rub (more than before) adding this engine and transmission which I expected to weigh a bit more than the super light transmission and (heavy) 5cyl OM617.

Earlier in this thread I had listed the weight of the OM648 with the 722.6 attached at the time I removed it from the CDI. That weight was 745 lbs.

The weight of the OM648 alone is 555 lbs.
The weight of OM648 plus the 6 speed transmission is currently 677 lbs.
The weight of the OM617 alone without transmission is 643 lbs.

I was running the aluminum 4 speed on the 617 which I'll bet weights about 40 lbs. Looks like there will be no added weight issues. Not that the W123 will be hitting any road courses but there will actually be about 100 lbs farther behind the wheels which should work out for better overall handling.

BirthdayBenz · #6 03-31-2022, 06:53 AM

I'm surprised how the mounts almost line up.

Phillytwotank · #7 03-31-2022, 11:31 AM

This is going to be Sweet! i'll be on the lookout for it crusin the carolinas

Oz Brown · #8 03-31-2022, 01:10 PM

Just stumbled across this. I'm just putting an OM613 with standard auto box into an old Armstrong Siddeley car. I am about to order a BlackSmoke racing standalone ECU conversion and gearbox controller so I'm interested to see how easy it is to get their system working.

BirthdayBenz · #9 04-28-2022, 10:16 AM

Roughly a month has passed and I've made less progress than I would have hoped for. Below is a photo dump. Looking at all of them now I guess I've done some things...

Made a trashy bracket from scrap aluminum out of the CDI:

Mounted and wired the CDI pedal. Also OBDII.

Fuel filter and pump mounting. Still need to order/build AN lines.

Intake pipe modified. (No I can't TIG weld aluminum) Had a welding service do this. I did remove and clean up the inside restriction on that pipe.

Then I decided the transmission needed to move up in the tunnel about an inch.

It might require some additional slight modifications with a BFH or bottle jack.

Things appear to line up nicely if I shoot a straight line from the output shaft to the pinion on the diff.

I also designed some engine mount adapter plates and placed another order with send cut send. I cant wait to put the engine hoist away and close the hood.

BirthdayBenz · #10 05-27-2022, 06:51 AM

I've yet to give up.

Fuel pump and lines are complete.
Wiring is nearly complete. I can power up the car and communicate with the ECU over OBD2.

The most challenging part so far has been motor mounts. My original hope was to just have adapter plates fabricated and use some existing Mercedes arm as in the photo below.

Nothing is fitting up the way I want. Either the starter is hitting the strut mount, or the engine is not centered the way it should be or the turbo actuator hits the body on the passenger side. All the mount arms have some specific angle which the mounting bolt passes through which makes actually bolting them down an issue also. I decided that the best way is to fabricate custom mounts. I've designed a mount using cardboard aided design and ordered laser cut steel from sendcutsend.

Most of my garage time the past week as been spent learning to TIG.

having this skill will also allow me to fabricate the down pipe. I'm almost feeling comfortable enough to attempt building the mounts.

BirthdayBenz · #11 06-02-2022, 04:26 PM

I made a downpipe!

I cut the flanges off of the CDI cat and then flipped the existing CDI front pipe exhaust section around then welded flanges back on and everything fits right up to the stock W123 exhaust. The only mod to the stock W123 exhaust was welding on the flange from the CDI as I wanted to use the modern clamp type flange instead of the standard old school two bolt one.

BirthdayBenz · #12 06-17-2022, 12:59 PM

Maybe I should have started this in the long term builds section.

I've finally made a motor mount for the drivers side and designed an adapter plate for the passenger side. As of today the engine is sitting on the mounts with no wood/hoist/jack stand supporting it.

Left:

Right:

I suppose I can try to start it now. Still need custom radiator, intercooler and piping. I think i'm going to try to use an intercooler from a BMW1 series. The CDI intercooler would require a lot of cutting away of the front end to make it fit. Unfortunately I'm pretty sure I need to remove my A/C to make the intercooler fit.

martureo · #13 06-17-2022, 01:08 PM

Crap, I'm sorry I didn't see this until now.

I've put a om603 into my s123 and I ran into a similar problem with the motor mount arms. I ended up using the stock w124 OM603 arms, but with spacers. I also opted to use the w124 style motor mounts as I wanted to reduce vibration into the chassis.

Shern · #14 06-17-2022, 02:44 PM

Have you spoken to forum member H3ffe?
His is a wagon though a smooth running version of your swap(it’s astounding).

BirthdayBenz · #15 06-17-2022, 07:29 PM

Quote:

Originally Posted by Shern

Have you spoken to forum member H3ffe?
His is a wagon though a smooth running version of your swap(it’s astounding).

I have exchanged a few messages with him. I'd like to see more of that car. I've only been able to find about 3 old poor quality pics of that car from when it was sold for an astonishingly low price of 6k. I also found a build thread which was only about 5 posts long on the superturbodiesel forum.