Howdy All,
Been another long time away. Back in 2017, the OM606 shifted forward from a pothole impact and clipped the fan blades off on the shroud. A few hundred feet later, major overheating warped the head and blew the gaskset. I was on the freeway up a hill with no margin and no where to bail out, so I had to keep going and watch the temps skyrocket.
I've spent the time since then on a complete rebuild of the chassis. Basically, in 2016 I stopped drinking, mostly because I felt I was getting dumber and more forgetful and needed to do something. Not an easy process, but I have a lovely family who gave me the necessary motivation to get and stay happily sober. Some people can love beer and not slide down a slippery slope. I am not one of those people, it turns out.....
The upshot is I have a lot more patience/focus/precision, and I've chosen to do The Last Complete Overhaul of this truck. Haha, but I'm partially serious. I want this to be the last time I completely rebuild core systems, and if I have to get in to repair something, I want that to be as pleasant an experience as possible. Nothing oily, nothing stinky, nothing itchy (looking at you, glass exhaust wrap), etc.... Everything designed to be R&R'd.
Essentially, I want to spend my time driving my Landcruiser, not fixing my mistakes....
I'm gotten through quite a bit of the to-dos, which I will outline shortly, and am now beginning final assemlby of a very similar but fundamentally different machine.
Mandate: A robust assembly designed for ease of maintainence and long service life.
1. I had the block bored and sleeved to Mercedes' spec. This was a very challenging thing to have done correctly, but the engine I bought, although low in milage, showed signs of significant neglect. My hamfisted first build didn't help anything, and there was heavy scoring on the cylinder walls from a time when I ran the engine without an air filter... So I've fully rebuilt the engine, re-doing all the things I didn't attend to and should have - balanced the clutch, injectors are professionally rebuilt, pop-tested and patterned. All new seals/gaskets, overhauled the hydraulic tappets, new rod & main bearings. New piston rings, crank magnafluxed and inspected.
2. Next, I sent off the head to Texas for straightening, a full valve job, and new exahust valves to be installed by Brooks Elliot. I chose him because of his reputation and prior experience working on performance OM606 heads. He did a wonderful job.
3. A core mandate of this build is that I want -no- leaks. No boost leaks, oil leaks, water leaks, gear oil leaks, zip zero nada. If I do it and it leaks, I re-do it till it doesn't. That means replumbing everything (every. thing.) with cunifer hard lines and AN fittings, with AN flex lines at the transition points. I've spent the last year collecting the necessary bending / flaring tools to do this in space-plane style.
3. I want things to fit without cramming. Everything must have the necessary clearances to move as needed, and restraints to keep it from moving further. To do this has required a serious design effort in terms of packaging. The drivetrain is very long, the truck very short, and the number of subsystems needed to keep it all cool is daunting. I begin by building an accurate (+- 2mm for critical dims) 3d model in Rhino of my truck, starting by using a laser XYZ locator I built out of linear rails to map the frame. Without the model, I would have had to assemble and dissassemble the truck over an dover again just to test different ideas. So I spent a couple months measuring the crap out of things, and then began fitting everything in and checking/re-checking driveline angles, etc. The end result I am happy with. Clearances are very tight - 1/8th of an inch in places. But they should be sufficient, and I've planned them carefully with future maintenence in mind.
4. The relocation of everything created a good opportunity to strip the frame down to bare metal inside and out, cut out the moderatly rusty rear frame member and last 12 inches of each rail. So I built a brand new rear frame, boxed the whole length, and added in some beefy sliders. Relocating for fit meant lowering the engine 2 inches and moving it back about the same. This meant I couldn't get away with my pan clearance anymore, and so I spent a month scrubbing
ebay.de until I found a pump and pan from an OM648 that I could afford. The 648 pan is rear sump, and the pump is a higher-output unit to boot. It took 6 weeks to get here from Germany due to the pandemic. Just like old times....
5. I'm sick of overheating, thinking about overheating. So I've added a massive oil cooler and a frozen boost air-to-water intercooler to (hopefully) end that conversation permanently.
6. I spent some of the time since the head blew up building a really fun offroad camping trailer. In doing that I upgraded my wiring skills. So, this build will feature a race-grade, fully sealed harness w/ Duetsch connectors, mil-spec crimp connections, tefzel wire, and all that sort of overkill. No more chassis ground, seperate circuit for everything, etc.
7. Part of 'no leaks' means re-locating the fuel tank out from under the passenger seat to the rear. I've built a 22 gallon tank similar to the con-ferr model out of some stainless I had hanging around. Since I was already going to be re-working the rear, I could make some good mounting provisions for this tank.
8. The old compound turbo setup was fun, but leaky in every way and oil drainage was insufficient. This time I started with a brand new Holset HE211 (more efficient than the old BorgWarner K14) and a new impeller on my HX35, and have fabricated a 100% aluminum intake w/ vanjay clamps for the connections. The hot side exhaust is mostly stainless, much more carefully fitted. Part of the over-heating issues derived from the excessive amount of hot pipe in the engine compartment. I've re-configured everything to minimize piping, and designed an insulation system that uses layered ceramic and aerogel (pyrogel XT-E) in a stainless wrapper to shroud all the hot piping I can. It's an approach based around some aerospace applications I researched, hopefully it does what I need. I had the Elbe Engineering tubular manifold ceramic-coated @ Jett-Hot, primarily to prevent rust. I'll take any heat reduction I get as well.
I'm pretty stoked to be beginning the assembly after literally years of planning and waiting and saving (anyone who's had engine work done probably knows what I mean by that. Holy cow getting good work done takes a looooong time....). Maybe with luck my kids will get to ride in Serenity again before they are grown...... (6 and 8, now....). I miss my '40.
Over the next few weeks I'll be uploading pics and details along the way. I apologize to the folks who I left hanging over the last couple years with unanswered questions. My soul was too sad from the head warping to log in here until I'd gotten a handle on things and turned it around.
Peace,
*gn