The sketchy coupe. OM603 swapped w123

I'm new to GRM and was told my build would be appreciated here. This is copied and pasted from the superturbodiesel forum so it may sound weird or be formatted oddly. The car now is in limbo, waiting to build the new OM606 and swap it in to something, most likely this car.

Figured I'd introduce myself and my project through this build thread. I'm a Mercedes tech at an indy in Richmond, VA. My younger brothers neighbor was paying someone to tow away his '85 W123 wagon and '83 W123 coupe. He ended up giving them both to me. The Wagon is a whole 'nother story. The Coupe had an OM603 with matching trans sitting in it. It also had the cut springs, factory 16x7 BBS wheels, Zender front bumper, euro rear bumper, and urban camo? hand painted paint job on it when it came under my ownership.  I focused on the wagon first and was able to get it running after a lot of work, I now daily drive the wagon. After a while I turned my attention to the Coupe. The previous owner (we'll call him Cap) informed me the engine was in unknown condition and the car was severely rusted, Cap had already replaced the driver side floor pan. My goal here is to build a somewhat enjoyable car for little to no money, as this is a fifth car for me and the condition of the car is, at this point, sub-par at best. Just to be clear, I know this build isn't most peoples taste, but it isn't mine either. We're just working with what we've got!

Here it is after towing it to our shop.

I first wanted to make sure this was even worth attempting so I ran a ratchet strap across the engine sitting in the bay, rigged up a starter solenoid glow relay, hook up fuel lines, a battery, and hit the starter with some power. Much to the surprise of everyone at the shop, it ran. And it ran pretty damn good. Project Sketchy Coupe is a go.

[video=youtube]https://www.youtube.com/6ktngIOqo0I[/video]

Progress is constantly sporadic and brief, but I try to have something in the pipeline on this car. After making sure the 603 ran I turn my attention to how to mount the damn thing in the engine bay. I did a little bit of research, and found out my 603 was out of a w126. I decided to attempt to mount the engine using the 126 mounts and spacers. I made spacers out of 3/8" steel plate.

I could only push it so far, and my boys were of no help at all. luckily my brother lives pretty close and came to the rescue.

3/8" spacer, and I also overbuilt a trans crossmember out of 3/8" as well.

Time to throw the engine in.

it pretty much lined up on the first try using w126 om603 arms and mounts with my spacers.

Cap had hacked the radiator top mount/support out in order to shove the engine in to the bay of the sketchy coupe. From what I understand he did this in order to avoid a fine from the city for have an "abandoned vehicle" on his property. This made it a real pain in the ass for me, as the frame rails ended up collapsing in by about 1/2" or so. I was using a 124 603 radiator I pulled out of the junkyard and it wouldn't fit. Rigging up a bottle jack and spreading the rails until my top mount fit again did the trick and I tacked it in place, threw the radiator in, began hacking up radiator hoses until it fit. I'm pretty unhappy with the expansion tank and how that hose is ran. It'll work for now and I was able to bleed it, miraculously.

somewhere in there I did an A/C delete, and the battery was relocated to where the back seat was.

Bungie corded the grille on for test driving purposes.

I attempted to swap the 126 tach into the 123 cluster in order to have a factory tach.

This ultimately did not work. the 124 crank signal runs through a few other components that I did not have. I had to figure out another way to get a tach without breaking the bank.

Somewhere along the way I decided to rip out the disgusting interior, and everything behind the dash. Weight reduction bro!

[video=youtube]https://www.youtube.com/QtohAbai9WA[/video]

I removed the ALDA, and turned up the pump a couple turns. I also rigged up a w124 om603 throttle cable to the w123 pedal. I ordered some ebay hood pins so I could throw the hood back on. I also cut a big hole in the hood for the exhaust. I drilled a hole at the bottom of the 90° to drain rain and such.

I wanted to make sure I wasn't melting pistons so I turned to ebay and bought some super reliable chinese gauges. I ordered boost, egt, an a digital frequency counter to attempt to make a tach.

Boost gauge was very easy to setup. After ordering some adapter fitting I was able to install the egt probe into the factory manifold as well. Here I am testing them out:

[video=youtube]https://www.youtube.com/Hs719kyZ_GM[/video]

They work! I can't imagine that egt gauge is incredibly accurate, but hopefully it'll keep me from doing serious damage.

I turned my attention to the frequency counter. I wired it up to a 5V power supply, grounded the ckp, and ran the signal wire to the frequency input pin of the counter. Had to change a few settings around on the counter and it worked! not bad for 8$!

[video=youtube]https://www.youtube.com/Fai1g0WlDVA[/video]

That's pretty much all my progress for the time being. I really need to throw tires, tie rod, clean up wiring, and a battery tie down before I do much else. The plan is welded lower ratio differential, hydro handbrake for skids, and more weight reduction to increase the fun of the car. If I had a higher budget I'd love to do a 5spd swap (we have a few E36 ZF 5 speeds laying around), Turbo, and reworked injection pump. I can't imagine this cylinder head can handle too much more abuse though.

As someone who (for 3 years)  daily drove a manual w123 with a om617 + vgt turbo + a2w intercooler swapped in it.....I 150% approve of this! 

What indy do you work at by the way? I used to be familiar with an euro shop in RVA.

In reply to yupididit :

Haha, that's awesome. I daily an 85 300td, so the Sketchy Coupe is a rocket compared. Hoping to double the current power with the 606.

We seem to have a lot of Euro shops here. At that time I was at The Shop. I'm currently extremely happy at Sportscar Workshops.

I want a 606 w123 coupe in the worst way but that much go in a w123 tin can would be scary. Gonna need a real rear end from a 116 6.9 or something lol

Gonna go ahead and reiterate Dibs on the coupe after the floor pans fall the rest of the way out haha. Love this strange hideous wonderful contraption.

You can make decent power with the 603 with a dieselmeken pump.  Seeing you already have it in the car, I would try that rather than a 606.  You can use a 603 modded pump on the 606 as well.

In reply to ccrelan :

$1700 though 

We're building an OM606 W123 pickup truck. The 606 will only make as much power as the mech pump swap in. But with a pump, intercooler and turbo you've got 500hp/700hp on tap. Hard to make that power for that money.

There is a guy on a Facebook Merc f/s page selling a 8mm dieselmeken modded OM603 pump for a $1000 obo in NJ

ccrelan said:

There is a guy on a Facebook Merc f/s page selling a 8mm dieselmeken modded OM603 pump for a $1000 obo in NJ

I don’t have Facebook,  but if there is an email or number listed do you mind either posting it or sending me a pm?

PM sent to Cotton with contact info

In reply to ccrelan :

Thanks,  I appreciate it.

yupididit said:

I want a 606 w123 coupe in the worst way but that much go in a w123 tin can would be scary. Gonna need a real rear end from a 116 6.9 or something lol

You want a 2.65LSD? How would that change the supposed scaryness? The chassis feels really planted in high speed cornering. The front end geometry only allows a little bit of negative camber but it gives a very "safe" feeling amount of understeer. The brakes are surprisingly good and with good new fluid hold up to abuse quite well.

hey all. im the guy selling the pump from nj. just thought id drop my ebay link here incase anyones interested. its brand new in the box still was just checked for damage after shipping and set up on a shelf in my garage. just trying to catch up on some bills some im unloading all my mercedes stuff slowly as i get to it in my garage. i got two 603's sitting on pallets 6 speed transmissions out of a c230 etc plus assorted other stuff. have a good one. this is basically what i wanted to build before running into some life complications. awesome build carry on! thanks again all. 

ebay

In reply to buzzboy :

Yes. The rear in my w123 was not up to the task on my vgt turbo setup. 

yupididit said:

I want a 606 w123 coupe in the worst way but that much go in a w123 tin can would be scary. Gonna need a real rear end from a 116 6.9 or something lol

The 185mm w123 diff should hold fine to mild 606 power.

corytate said:

Gonna go ahead and reiterate Dibs on the coupe after the floor pans fall the rest of the way out haha. Love this strange hideous wonderful contraption.

She's all yours if it comes to that. We'll do whatever crazy rotary swap you want.

ccrelan said:

You can make decent power with the 603 with a dieselmeken pump.  Seeing you already have it in the car, I would try that rather than a 606.  You can use a 603 modded pump on the 606 as well.

Well that's the plan. Om603 has cylinder head problems and comes with a pretty weak trans. I already have a 606 and 722.6 in my possession. May as well build that and put the om603 in my daily.

buzzboy said:

We're building an OM606 W123 pickup truck. The 606 will only make as much power as the mech pump swap in. But with a pump, intercooler and turbo you've got 500hp/700hp on tap. Hard to make that power for that money.

It was probably you I spoke to a few weeks back. Did ya'll come pick up some lifts from Sportscar? 

ccrelan said:

There is a guy on a Facebook Merc f/s page selling a 8mm dieselmeken modded OM603 pump for a $1000 obo in NJ

Brand new dieselmeken pumps are only $1100, seems steep unless it's unused. 

Tjones_W123 said:

It was probably you I spoke to a few weeks back. Did ya'll come pick up some lifts from Sportscar? 

Those were a few of my teammates, yeah. I'm a few thousand miles away from the build sadly.

In reply to Tjones_W123 :it is unused. 

This is awesome! I daily drive an 84 300d. I just scored an imported 84 300d na manual with green interior as a project.  I'm pretty sure those are mercury grand marquis wheels. Do you know what size spacers/adapters are on it? 

buzzboy said:

We're building an OM606 W123 pickup truck. The 606 will only make as much power as the mech pump swap in. But with a pump, intercooler and turbo you've got 500hp/700hp on tap. Hard to make that power for that money.

That actualy has my interest

116 "utes" were apparently common down in Australia.

An S123 with an OM606 would be a dream, both for fun and just for the sheer fact that it'll return decent fuel economy on road trips.

The 603 isn't a bad motor itself, just not as capable as the later and more updated 606; there's someone in the Ford truck world stuffing a 603 into his F-series.