r129 diesel conversion - Page 4 - PeachParts Mercedes-Benz Forum

mach4 · #46 04-01-2015, 10:45 AM

On the tranny cooler lines you could probably go with steel braided hose and AN fittings if you don't want wrestle with the stock lines. I think -8 would be fine and maybe even -6 would be OK. Cut the hard lines where you need to, weld on the AN fittings, determine your optimum routing and measure up the distance then make up the hoses. In fact you might be able to go all the way to the cooler with the hose by welding up an AN fitting back-to-back with the fitting on the cooler. Aftermarket coolers are available that might give you yet other options.

Stock would be better but these are other options to consider if necessary.

bkc · #47 04-11-2015, 01:32 AM

Just an update to keep the thread somewhat active...

Haven't gotten a lot accomplished on the project in the past week or so. Keep having to deal with previous owner wiring chaos or parts unavailability (or extortionistic pricing).

For example, my r129's ignition switch wiring:

I did figure out that the missing plug for the tranny is the electronic speedometer plug. Still trying to find where my indy shoved it to get it out of the way (hoping it didn't get pushed into the center console area where I will have to disassemble the whole thing to get to it again...). And someone suggested using a spark plug boot to replace the ruined one on the kickdown plug. Will try that when I am working under the car again (have been focusing on wiring currently, including separating out wires to disentangle them and remove extraneous ones, then rebuilding as new harnesses, complete with protective heatshrink and such).

Ah well. At least I still feel like I am making progress. Just a lot slower than I expected.

bkc · #48 04-27-2015, 03:25 PM

So, I've seen lots of posts online about how I can just send out the gas tank to a radiator shop to have it cleaned and resealed, in order to make sure the galvanization (or more specifically, the zinc) won't be an issue.

However, I have now tried close to a dozen local radiator shops, and they either don't do such things, or they claim the only resealing coatings available are not compatible with diesel. I am going to try the boating/marine places next, but I expect they will be much more expensive than a radiator shop would have been.

Any thoughts? If it matters, I am in the Seattle area.

Thanks!
-bkc

mach4 · #49 04-27-2015, 04:34 PM

Are you sure you need your tank cleaned? The one in my 107 has been fine - no cleaning or other mods done to run diesel (have 75k miles on it to date). I did swap in the diesel strainer however which is a lot coarser than the gas one. I'd be tempted to take the screen out and maybe run an additional filter, or see if you might be able to adapt a diesel one.

Notice the difference

bkc · #50 04-28-2015, 01:27 AM

Yup, have a new diesel strainer (they all seem to fit, so I picked the w124 one so I can easily get the cheaper feed lines - w140 line is $120 wholesale, versus $12 for the same line for the w124!). I think I learned about that strainer difference from reading your (mach4) conversion thread a while back.

As for the zinc/galvanization, lots of major tank manufacturers specifically mention that as a reason to not use gasoline tanks/containers for diesel. Given that I plan to run both regular diesel and biodiesel, I was particularly concerned about it dissolving the zinc in the coating... At this point though, yeah, I'm thinking I am going to have to just go ahead with using the tank as is (it is in good shape as far as I can tell - old screen came out spotless, no apparent corrosion or rust at strainer, sender, return, or breather connections). At least it is something that can be done later, although it would be much more convenient now (empty, already out of the car).

On the plus side, if I just go with the tank as is, once I get the replacement o-ring for the fuel heater thermostat the fuel system will be complete. One more major checkbox checked on the conversion.

bkc · #51 05-10-2015, 01:24 AM

Quick update just to keep this thread alive. Sorry I haven't been able to proceed at a faster pace.

Finally found a radiator shop that understood exactly what I wanted for the fuel tank. Dropped it off for an estimate today, hopefully will be reasonable. (My concern regarding zinc in the galvanization and diesel fuel was confirmed by several marine engine/fuel folks, who see that kind of problem all the time on ships.)

Refurbished the fuel heater thermostat unit on the om602 while it was already removed from the motor. New o-ring, fresh spring, new lock ring, new hoses, new hose clamps.

Filed down the sharp edges on the tranny crossmember and painted it to protect it.

Took advantage of a NAPA oil sale to get two gallons on 10w40 standard oil to be used during the first few hundred miles as a sacrificial oil load to clean things out and then get changed once things are running well. Didn't see any reason to spend on the good stuff until it is going to stay in there for a while.

Removed the hard top so I can start fixing the back window (cracked) on the soft top and replace the mostly-seized left rear top lock. Will also flush the hydraulic fluid once that is working. Will hold off on refurbishing the hydraulic cylinders until the car is working reliably.

Seeing the car with the top down was re-inspiring. Not sure if it is just the change versus what I've been staring at for months or whether it is actually the having the top down, but it is making me smile each time I see the car now.

Soft top is still in good shape other than the crack in the rear window plastic. Was concerned after it had been folded for so long.

Used my MityVac to identify which fuel hardlines were feed and return. Was totally not expecting there to still be lots of liquid gasoline in those lines (they've been open at both ends for months). It seized up the MityVac, since I didn't have the fluid catch container attached. Fortunately, it seems to be fine again now that I have fully disassembled, dried, and reassembled the unit. Glad it is one I can take apart to clean/fix like that.

Figured out fuel hose fittings. Would prefer the nipple style, but these gentle barbs should work fine with hose clamps, especially since I can leave the hose attached and unscrew the hose and fitting, so don't really need to worry about being able to remove/reinstall the hose. The two for at the engine compartment end of the hardlines were inside the pre-made fuel hose lines, I just carefully cut away the old hoses. The one for the rear (originally from pumps array to hardline) was same idea, but more difficult, as it was crimped, not heat shrunk. (I am sure there is a tool for that, but it started tonight as just "I wonder what is inside the crimp? Can I use it?")

Am reinstalling the hood pad the previous owner's wife so proudly had installed herself. She clearly didn't use the right glue, as it had completely unbonded and was hanging down. I barely had to tug most of the edges once they were untucked or unriveted (those plastic two part inserts). Will get the right glue and redo properly.

Removed and inspected the vacuum pump on the om602. Is one of the newer revisions (external torx screws) but was still the same bearings that can grenade design inside. Looked in good shape, though. Will plan to replace it once things are up and running. Put the new metal gasket in to replace the paper one (good thing I got it, since the paper one disintegrated when I removed the pump).

One concern I had when reinstalling the vacuum pump was that I couldn't turnt he engine at the crank bolt. Had just replaced the pump on my '87 om603 a few weeks earlier, so knew it should turn. Hopefully is just that there are no fluids in the motor and maybe fighting some pressure internally. Will try loosening some glow plugs or injectors and try rotating it again. Hopefully everything is okay inside, otherwise that kind of blows up the whole point of this project...

Anyway, that's where I am so far. Hopefully will make faster progress on it. We're already getting into convertible weather, surprisingly!

vstech · #52 05-10-2015, 08:21 AM

Nice.
Has the motor been rebuilt? I cannot imagine why the motor would not turn over...
Certainly pull all the glow plugs and see if it's liquid holding it still...

bkc · #53 05-15-2015, 02:49 AM

Finally got a chance to work on it again today for a bit.

No, the motor wasn't a rebuild. But it ran great when parked, and we had had the timing chain and such replaced just a few months before the Domino's driver crashed into it. All the vacuum lines and several solenoids for the turbo system were replaced in 2005 when we broke down in Minnesota on the way home from buying it off ebay.

Anyway, pulled the injectors, one by one. Once the last one had been pulled, the motor turned normally. Hooray!

Only problem is that most of the little plastic clips holding the injector lines in place shattered no matter how carefully I tried to remove them. Hope I can find them and they aren't too expensive. Also, the plastic collar around injector #2 was in pieces, I had to make sure nothing fell into the prechamber.

The injectors don't look too bad. The usual light coating of carbon. Only #1 looked at all questionable, with more carbon and some oil goo or something. The holes could use a cleaning, though. What is the best way to do that without risking stuff falling into the prechamber, or worse? I really don't want to add any major work on the motor to my project at this stage. (I plan to later on, after I've gotten to drive it around a while, pull the motor again and replace all the gaskets, lifters, etc. Not a rebuild, but a refurbishing, I guess, of the usual suspects.)

Injector #2:

Injector #1:

Injector #2 socket:

The leak lines all pretty much disintegrated, but I probably should have been replacing them anyway.

By the way, in case anyone cares or does a search on the vacuum pump, the one on this motor is 603-230-01-65. It has the external torx screws, but still has the old style bearing wheel inside which can grenade into the timing chain.

jay_bob · #54 05-15-2015, 06:26 AM

Send the injectors to greazzer down here in SC and he'll make them look new.

Definitely replace all the injection line support clips, they are critical to keeping the lines from moving with vibrations.

bkc · #55 05-24-2015, 01:23 AM

Another update. Really need to more firmly schedule time to work on the project to get it done!

Was able to order most of the injector hard line clips from the dealer for about $1.50-$2.50 each. Realized afterwards I should get them for my '87 300D also, since I opened the hood to check something else and noticed (only now?) that they are just zip-tied to the metal brackets...

Replaced the broken top lock which was making things really inconvenient. Kept having to make sure whichever top didn't slip down in and lock. With the soft top up and out of the way (see an update or two ago for removing the hard top), finally went and replaced the broken lock (part of the whole automated hydraulic top system) with a used one I had gotten off ebay almost two years ago. Now the top system should work properly. At worst, it will easily work manually, now. Although I expect it should all work fine, since the lock was the only problem with the whole complex system prior to the old engine dying.

It had taken hammers and prybars to get the lock to release this past time. You can see the damage here:

(Good one on top, broken one on bottom)

Also got the fuel lines and injectors done. (Left off the leak lines for now, in case I need to remove the injectors again. Easy enough to install those lines at the end. Already have fresh line and end cap on hand.)

Had to remove the intake manifold in order to get to the return clear plastic line and replace it (is on the back side of the injector pump). Is there some secret or special tool to reach the middle lower bolt on the intake manifold? I spent as much time getting that one in and out as all the others combined, since I had to hand turn it with just an allen key, rather than anything that could ratchet or at least just keep turning... Maybe a really really long 6mm allen key would work? Will have to see if I can find one like that.

Anyway, cleaned and brass wire brushed all the bolts, both for the manifold and the banjo bolts (IP, filter, clear hard lines). Nice new fuel clear plastic lines, new primary fuel filter (already have a new inline filter attached to the fuel heater unit), new o-rings where appropriate, hopefully all good to go now for the front fuel system (still need to reinstall the fuel tank and hook everything up back there, but I already have new and/or freshly cleaned lines and strainer and vent valve and rubber seals back there; should be just a matter of installation/assembly next time I go under the car).

Old clear lines:

New clear lines, installed:

Overall, it took me several hours to carefully clean the injector sockets and around them with q-tips and such to make sure nothing got into the prechambers (hopefully!). But, once they were off to let the motor turn, I couldn't see just putting them back with all that gunk around them. I figured it would get in just from reinstalling them. The old plastic collars are NLA and allegedly no longer required anyway. Makes sense, they did seem to just trap the gunk. Will be much easier to keep clean in the future now (without the collars).

As always, hopefully will get more done soon. This is moving way too slowly. Need to prioritize it higher. I want my garage back, and I want to actually get to enjoy the convertible during the summer. It's not like I live in sunny southern California!

mach4 · #56 05-24-2015, 10:45 AM

Quote:

Originally Posted by bkc

As always, hopefully will get more done soon. This is moving way too slowly. Need to prioritize it higher. I want my garage back, and I want to actually get to enjoy the convertible during the summer.

If I could make a suggestion at this point....focus on just making it fit. There will be plenty of time later to make it run, make it stop and make it pretty. If there is something that prevents getting the engine/trans in there and mounted where nothing hits, everything else is pretty much irrelevant. Then you can focus on hook-up, taking one system at a time, focusing on what will get it minimally on the road - cooling, fuel, electrical, exhaust, control, steering, vacuum, etc.

bkc · #57 05-24-2015, 02:49 PM

Hi, mach4. Always happy to hear your advice!

The motor and tranny do already fit. Paid a ridiculous sum to a shop (in retrospect, would have experimented on my own a lot more first) to modify the crossmember and alter/build mounts. As it turned out, I will probably end up throwing out most of that work eventually, but it should work for now. I am at the stage(s) of trying to get it minimally on the road (first goal: out and back into the garage on its own).

Guess this is a good time to review where I am...

I think I have the electrical stuff almost all figured out, wiring-wise. Still need to figure out how/where to run and mount the wiring in some cases. Need to figure out where to mount things in the electronics bay. A few minor solderings still to finish, once I decide what kind of plug I want for the misc connections (e.g. preglow/starter wiring). But the wiring has been deciphered, I think. Climate control may be dealt with later if it gets too bogged down.

Fuel should now be all ready to finish assembling, which should be straighforward. All parts are now present and ready (new, refurbished, or cleaned, as appropriate). Only pending item is purging any remaining liquid from the two underbody hardlines before assembling everything.

Exhaust will be a combo of the w124 and r129 piping, cutting off the mangled resonator from the w124 wreck piping and using the r129 resonator (should be minor metalwork for an exhaust shop? r129 resonator has a bracket on its pipe already), then having a custom connection built for exhaust manifold to muffler. I was planning to just modify the r129/m104 first segment, but then it got stolen by metal thieves. But, still, should just be the flex portion and a bent pipe. The fittings will be the only real issue, I think? The w124 pipes actually seemed to fit fine when I did a test hang a month or so ago, although that wasn't a complete install, so I could find complications.

Transmission is 722.500, so the first four gears are the standard vacuum control, which has been hooked up to the compatible om602 vacuum system. I'm not sure on the wiring for the 5th gear as yet. But, the default function of the system with no controller is 1-2-3-5. So, it should work well enough to test run or to get to and from a shop for work. Can always short the signal so it does 1-2-3-4 and ignores 5th, but that defeats the point of having the 722.500 instead of fitting the 722.418 from the w124.

Steering just needs new low pressure hoses and a fluid fill. Retrofitted the om602 mounting bracket onto the r129/m104 steering pump, so the one hose fitting would match. The bracket was just a matter of swapping a bolted on plate, and the pumps were otherwise interchangeable other than one fitting being a different OD. Have a fresh filter for it already, also.

Vacuum seems basically the same between the two cars, so that was straightforward to connect. Even the turbo solenoids maze wasn't too bad to figure out. Probably helps that the turbo vacuum system was rebuilt in late 2005 when we got the car -- it broke down in Minnesota on the way home to Seattle after buying it in Chicago off ebay (alternator was dead, as was the indicator light, and that's when we discovered the turbo vacuum system had failed). So, relatively young and still flexible vacuum lines, connectors, solenoids, etc.

Cooling is one of the major things where I still need to figure stuff out. The r129/m104 radiator has both connections on the left, om602 needs top left, bottom right. The v8 and v12 r129s look like they have radiators with appropriate connections. But there is the uncertainty of a used radiator, or the cost of a rebuilt/new. Versus running some sort of hose or piping connection to bring the lower right motor hose to the lower left of the radiator.

Need to find an L-bracket to use to mount the oil cooler under the left headlight area, like in the w124. The r129 fender structure is too lumpy to just bolt it on as I had hoped to do.

The other sticking point is I still need to find or build a box and bracket for the air filter.

Also, need to replace a few smaller coolant lines in the heating system which run through the electronics bay, since will be a huge pain to get to once the electronics are back in there (and at least two of the hoses look swollen). I want to replace as many coolant hoses as I can, since the m104 had a bad head gasket for ages, with lots of oil in the coolant. Old hoses were sticky and swollen, other than the couple I had already replaced when it was still running. Probably need to flush out the existing radiator if I do keep it (was a recent rebuild, according to PO, so should be in decent shape despite the oil in the coolant?).

Still trying to decide on how to turn off the motor. In theory can use the w140 300/350 SD shutoff solenoid system, but not clear whether that fails to staying on, or cutting off. Definitely want my failure mode to be that the motor keeps running, so leaning towards building some sort of adapter to the ignition that will add in a vacuum valve, or a solenoid that just holds power for 3 seconds or so to do the shutoff only when it gets power from the key going into position 1 or 0.

AC compressor from the r129 doesn't fit the om602 bracket, and the om602 compressor doesn't fit the suction hose fitting. Am hoping to find a way to modify the m104 mounting bracket or find a relevant bracket off a w140 om603. Even if I don't get the AC system up and running until later, I want all the openings to be closed up with the hoses and such, and I need the compressor installed for proper serpentine routing. (Although, in a worst case, I assume there is a serpentine for non-US, non-AC om602, or just fit the w124/om602 compressor and seal over the openings.)

I think that is pretty much everything, although I am sure I've forgotten something. The biggest issues holding me back right now are the physical placement and mounting for the turbo solenoids, the wrong-side radiator connection, all the engine compartment wiring, and the various control units that go in the electronics bay. Except for the cooling hoses, those are all hooked up, just hanging unattached. And, of course, the bazillion little details and complications along the way.

97 SL320 · #58 05-24-2015, 04:32 PM

Fifth gear should be a solenoid so an on off switch would be enough for now, I'd be concerned that the jump from 3 to 5 would be too great causing clutch wear / poor performance.

mach4 · #59 05-24-2015, 04:47 PM

My bad!!! I had a temporary loss of orientation on the project. Thanks for the review. I think you're making great progress and on the right track.

bkc · #60 06-08-2015, 06:30 PM

Minor update to keep the thread alive...

Fuel tank is back in, and the fuel filler door is labeled as DIESEL.

Found a fair amount of rust under the spare tire sombrero when I was cleaning the trunk during fuel tank install. Must be from when the third brake light seal went bad (per previous owner and common problem seen on forums). Will get that fixed once car is up and running. Soft-top hydraulic pump and reservoir and lines looked healthy down there under the sombrero, at least.

Starting to put the electronics bay back together. Still can't get the ABS unit unbolted from the large frame that holds all the ECUs. Guess I will have to live with it for now. Maybe I can drill out the bolts, we'll see.

Cleaned and dielectric greased all the relays and fuses in the main fuse/relay box.

Figured out that I can use the om602/w124 AC compressor (10PA15C) and its suction hose (since these fit with the motor and bracket) and just have the ends recrimped with new hoses for proper length/fit, instead of trying to retrofit the m104/r129 compressor (10PA17C) to the om602 bracket. End fittings are the same (thank you, Mercedes!), even after removing the fuel cooler unit. So, the AC stuff should be all set and done, once the radiator and condenser go back in at the end. Planning to do a reseal of the compressor, and of course fresh o-rings and dryer, before actually charging up the AC later on, but it should all go together now. Bracket and compressor and suction hose (still old length) are reinstalled.

Anyone need a fuel cooler?

The current slowdown is mostly from two things:

1. the parts are so messy (from the old diesel, and even more so from the leaky m104, and general age) that I am having to thoroughly clean almost every part being reused just to handle and install reasonably, not even for appearances reasons

2. I am trying to buy a repair shop, so the business and finance aspects are taking up a lot of time

That's all for now!