Mazda B2600 with OM617A, 1987 "Mazcedes"
The Chevy pickup had done yeoman service for quite some time, but it was getting very tired and nasty on the inside, ever since the leaky windshield replacement debacle, and the engine had started oil-fouling plugs badly. I could never get it started when I wanted, which resulted in me using it less and less. Which made for bad gas and the starting/running problems worse... a vicious cycle.
All of this could be dealt with but... I was sick of it.
I had been toying for a few years with the idea of finding a 1996–1998 12-valve Dodge Cummins, with regular cab, long bed, 4×4 and a stick shift, but those aren't all that common and go for stupid prices, even with 400kmi on the clock. (All-mechanical engine, bulletproof inline Bosch P7100 injection pump. Just like my truck, and basically the Dodge diesel equivalent of the Chevy, which was otherwise perfect for the uses to which it was put.) Not much joy on that front.
At dinner one day a neighbor showed me this Craigslist listing for a diesel Mazda truck. (He wanted it, but his wife put the kibosh on that.) I basically yawned, stating that I didn't really want to get into an orphan diesel model, of a truck and engine I knew nothing about. He then pointed out that this was a Mercedes diesel engine, one I was very familiar with, and that the truck was a 4×4 with a manual transmission. A 'Mazcedes'?
All of a sudden this thing got very interesting, as a potential replacement for the Chevy. Diesel engines can sit for years and start right up, which is perfect for a woods truck. The smaller truck won't hold/carry as much, but for on-property use you just make a few more short trips, and the smaller body might be more maneuverable in the woods. I thought about it, but procrastinated a bit too long and when I finally went to call on it the listing was gone. Oh well.
Later, though, I found a browser window left open to the listing on my desktop computer, and the phone number was still there. I called. Yes, it was still available, and I had some excess funds left over from the totalling of the Dodge diesel, so I made arrangements to go see it.
1987 Mazda B2600 LX Extra Cab 4x4 with a 3.0L 5 cylinder (OM617) 1983 Mercedes 300SD turbo diesel engine coupled with the Mazda 5 speed manual tranny. Great fuel economy between 25–30 mpg. Here's a few things done on it in the past 15k miles that I've owned it:Sale pictures:
Just had engine oil change done. Has aftermarket towing brake controller, turbo boost gauge, battery volt gauge, custom headlights, fog lights, CD player, battery and starter replaced recently. Has 265/75/16 tires on it.
Body has close to 200k miles, engine has close to 180k miles, 19k miles driven after the engine install. Has some dings and dents, small rock chip in windshield, truck bed handle broken. Family growing, so we just bought a bigger truck. Call, text, or message for more info. $2699 obo
The radiator and oil cooler protection are fine for normal use, but in the woods I think I'll need a little bit more. Will have to give this some thought.
PO says that the truck had an OM617 in the bed when he got it, leftovers from the turbo conversion by the PPO, and which he had sold. He had once left the hood unsecured, and it blew up and mashed the cowl area and damaged the hinges, but did not break the glass. Still looks good enough to me, for a woods truck.
Later that day Daniel and I drove to town in it to get some more brake cleaner for the delivery valve job and some dinner, and I filled it up. The aftermarket fuel gauge is flakey, and is not to be trusted. The oil pressure gauge is not hooked up.
Thumb starter switch, a toggle for glow/kill. Key does nothing but power the gauges, etc. I like its crude elegance, but wish the original instrument cluster could have been preserved.
The glow plugs are hooked up with a Ford starter relay, the 12ga wiring somewhat inadequate, since it's a single wire to one plug and chained to the others. The glow plugs all seem to be working, and I put the battery on charge, it was thirsty. Motor mounts standard Benz, screwed to perches welded forwards of the originals. Left side mount oily and collapsed.
There is a strange blowby oil recovery system. There are a couple of metal bottles, like pill bottles in size. First bottle drains to oil return and also feeds second bottle, second bottle is open to atmosphere, rather than being fed back into the air cleaner like stock.
Truck should have 215/75/R15 tires, which are 4" shorter than what is on it. (265/75/R16, 31.6" in height.)
Son dislikes the name "Mazcedes", prefers "Otto von Hirohito." I am unconvinced. "M&M" has also been suggested.
I used some heat-shrink tubing to slip over the hood retention pegs, maybe that will tame the horrible squeaking that comes from there sometimes.
The donor truck in the yard had an intact muffler, with hangers and mounts, which I bought. Should be fairly easy to mount, it's all formed to fit this model of truck. I just need to cut the pipes off appropriately and weld them together. That will be much safer in the woods, ensuring that no sparks can possibly come out of it.
I found that up front there was a missing bracket between a collar on the pipe and the rear transmission mount, so the exhaust pipe rubbed against a cross-member. Noisy! A section of shackle bolt from the scrap pile, along with a spacer made from a flex disc bushing and a scrap nut completed the ensemble. It actually looks nearly professional! At the back the new tailpipe contacted some over-long mudflap screws, but a short session with the grinder fixed that. A little over 2 hours for all of this.
It runs a lot quieter now! And, more importantly, will be safer in the woods.
Daniel and I then used the truck to do a lot of reversing practice in the driveway, preparing for his driving test. This little truck was nice for that because we could put it in 2L (4L with the hubs unlocked) in order to have a gentler introduction to maneuvering in reverse. (Eventually we switched to the 190D, which is what he'll be driving most of the time.)
As it rained intermittently during this and we were using the heater to dispel fog, it is clear now that the heater vent control is entirely disconnected from anything; I was unable to get anything out of the defroster vents. I guess I'll have to go in.
Back on charge.
(Depending on how well the Ford works out, and Jill's wishes, we could even end up selling the V10 too. The Ford's cab is a lot smaller and it's a stick shift, which while ideal for the woods could be less desirable for Jill, so this is not a given; we'll see.)
Recalling my last attempt to start it, and the overheating of the knife switch disconnect at that time, I replaced the disconnect with one of the cheap screw-knob disconnects I picked up recently. They're not rated for much current, 135A continuous IIRC, but mostly I believe that's because they've got a plastic insulator that's intended to allow for a quick on/off via only a few turns of the knob, routing all the current through the bolt that has the plastic knob on it. I've removed the insulator altogether, allowing for much more direct metal-to-metal contact area between the two body pieces of the disconnect. (In compensation, though, to disconnect you now have to completely remove the knob and move the terminal out of the way.) I had to re-route the negative wires of the truck to around the front of the battery, because the terminal now connects at 90° from its former orientation, a couple of inches towards the front of the truck. The disconnect's truck-side terminal is slightly smaller than the battery terminal, and the truck's terminal clamp didn't have any more clamping range left. I cut a 1/2" ring of copper plumbing fitting from the junk box, and slit and filed it so that it could compress. I wedged that into the truck's negative clamp, and wedged the disconnect's terminal into that. It clamped down nicely afterwards, we'll see how well it works next time I go to start it.
Assuming that all this works better, all I've got left to do is to fix the heater vent control lever.
I checked the parasitic draw on the battery, and it's what I would consider fairly high: 20mA. (Steve says that the current industry accepted limit is up to 50mA, which is ludicrous for anything that is not being driven daily.) I wonder if the brake controller might be to blame? The only other candidate is the radio.
I did have the bright idea to (soon) liberate the trunk emblem from the parts-car 240D (W123) in the woods and lash it to the expanded-metal radiator grille. A "Mazcedes" needs a tri-star emblem too! That shouldn't take long, assuming that removing the star from the trunk goes well.
I started pulling the dash apart, enough to liberate the heater control panel. The upper control's pivot had sheared off, and the control wire was kinked. (Related? Probably.) Trying to straighten the control wire broke it. I should get some junkyard parts to replace this, the wire at least. (The control panel itself can probably be glued, if necessary.)
I then wired the charging connection permanently to the battery, on the battery side of the disconnect switch. That should do nicely.
I installed the replacement heater control panel, it's an exact fit. There are a number of broken plastic pieces in the area, I'm starting to glue them back together so that things will fit and work correctly. That is slow. Little dabs of Shoe Goo, the occasional washer and/or clamp...
There seems to be one instrument cluster bezel retaining screw that is not there, nor is the metal clip that it screws to.
All that's left on my list is this fastener, and repairing the broken fog/driving lamp wire.
One of the fasteners I liberated yesterday fit well enough on the dash, so now the instrument cluster bezel is tightly secured. Perhaps it will help cure some of the buzzing in the area? We'll see.
All done, except I have been wondering if the screw-type hand fuel primer pump leaks air, which could help explain its very difficult to start behavior this Spring. (They can do this, leaking air, when the gaskets get old, especially when sitting. They can leak both fuel and/or air, depending.) You can get a new push-only type primer pump, but that's money and time. I have partially repaired these before, so I found my 90° 24mm wrench and removed the primer pump. Yes, the air-side gasket was badly decomposed. I got out my gasket punch set and punched a clean 5/8" hole in a sheet of Buna-N rubber scrap. (The 3/4" is a bit too large, it doesn't seal well enough against the plunger.) I cut a roughly 3/16" ring around it to make the washer shape, then rolled it over the body of the pump from the small end. Working it into place so that it tightened into the groove in the plunger, I was able to screw it down and it seemed to seal against mouth pressure on the open end. I installed it back on the truck, and then primed the system. Because the impossible-to-replace fuel seal inside the pump is old, it made quite a mess due to leaking fuel while pumping, but I was still able to pump fuel, and get it circulating through the system well enough to hear the check valve buzzing. I then tightened the plunger down against its brand-new air seal.
I put the block heater on while I wrote most of this up, then went out and started the truck. It started easily.
I took the truck for a quick spin up and down the hill, the badly rattling dash seems to be no more. (Amazing what putting things back together correctly can do.) However, I smelled hot friction material when I parked, and a quick survey showed that the front left brake was very hot. Sigh.
I removed the caliper and drove to town to get a replacement at NAPA. It came out to $41.15 total, with the AAA discount, but I had to drive to a different store to fetch it. They wanted the core kept at the first store, where I paid. Back home I put it back together, it was pretty easy. It got new copper sealing washers and a new hollow bolt, which came with the rebuilt caliper. I cracked open the bleeder, packed modeling clay around the threads to prevent air incurson, slipped an 8mm box-end wrench over it, then attached the Mity-Vac bleeder kit, and filled the brake reservoir. I then pumped the Mity-Vac until no more bubbles came out, broke the vacuum, and tightened the bleeder with the wrench. Quick, and easy.
I then put the truck the rest of the way together, and topped off the brake fluid. The lug nuts were all on the loose side, on all the wheels, so I snugged them all. I took it for a quick test drive and re-bedded the brakes. No problems.
Because it turned out that I had not brought all of the brake caliper with me to the store, I then took the opportunity for a longer test drive while returning the remainder of the core. The truck drove and braked fine, and did not pull to one side.
Now maybe it's ready to deliver.
The dash lighting is also wretched: the fuel gauge, and particularly the voltmeter, are blindingly bright at night. The fuel gauge is on the dash dimmer, but as its lamp is a white LED its brightness and color, and its voltage/illumination curve, don't match anything else in the dash. The voltmeter is just this nasty bright blue LED thing, which has no reaction to day/night. Ugh. The tachometer is not lit. And, of course, there aren't any turn signal indicators. The dash desperately could use a bit of a re-do. But, it's not something you'd usually drive at night, and it's leaving me tomorrow, so...
Also, the voltage regulation was erratic, according to the nasty voltmeter. Brush pack? Poor wiring connection? Crappy meter?
I stopped for fuel on the way home. Around 10 gallons, just about 20 MPG. Should perhaps have been better, but this is what I would expect from this engine under these conditions. I think it'll do better on the long trip.
Last night the shrink tubing I'd installed on the hood pegs proved inadequate, the squeaking had gotten pretty continuous as the vibration had caused the hood to saw through it. I pulled the remains off and cut two .410 shotgun shell plastic casings free from their bases and twisted them down over the pegs with pliers. I used a heat gun and an awl to poke the holes for the cotter pins. This is pretty tough plastic, we'll see how it holds up on this trip. Because it's thicker plastic the diameter is larger, it's kind of hard to put the hood down all the way now.
I put the block heater on while I got cleaned up and dressed for the trip. Should make for a nice easy start. (It did.)
I spent the day bopping along at 75 MPH, the boost gauge showed 5–6 PSI at speed. Fairly noisy, no way I'm going to use the radio, that'd just add to the stress.
I locked the truck (after I filled up mid-trip) when I went in for a snack stop. When I tried to unlock the driver's door, it wouldn't. Nor would it open from the inside. I spent the remainder of the trip clambering in and out over the console. Sucked.
The truck just doesn't seem to have the power it should. While I fought a pretty fierce headwind most of the trip, it still seemed underpowered. I know it's got boost, I believe the gauge, but that doesn't mean that it's getting the additional fuel to go with it. The OM617 NA engine is some 88 HP, with turbo boost and additional fuel it's 120 HP. The experience felt a lot more like a NA experience than a turbo experience. Floored, uphill into a headwind, top speed could drop to as low as 50 MPH in fifth gear. (The ALDA may be malfunctioning, it's certainly been messed with as the anti-tamper cap has been removed.)
I parked it at the farm, after a long and fatiguing trip. That's the last time I'm going to be driving this truck.
I showed Steve the engine compartment, to satisfy his curiosity. The turbo/ALDA plumbing looked plausible, the boost gauge is tapped right at the ALDA, so that potential cause of low power can probably be eliminated. Whether the ALDA itself is working is a different question. The fuel pre-filter looks pretty dark. I wonder if it's clogged a bit? Slight fuel starvation could also cause power problems. That would be an easy and cheap experiment.
Driving the replacement truck was a much nicer experience. That Ford is, and always was, indeed a nice truck. Still, the Mazcedes will be fun for short trips, and is a lot smaller. Which, if you don't need the payload room will be superior. Even if the turbo's not working correctly it won't matter much for the uses this truck will get.
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