68 Unimog 404 Restomod

[SuperMochombo]

I hit a milestone today, and it warrants a new thread. The engine finally fired and I got it to run for a few minutes, just idling. Runs rough, muffler half gone so it pretty loud. Smokes like crazy, no trustworthy gauges but....products on the way.

I'm thrilled. Doing handsprings. I'm almost driving!

Today I cleaned out the carb, cleaned off the spark plugs, confirmed firing order, cleaned out under the distributor cap, and after a bit of ether, she fired and ran for a very short time, no input from throttle or choke. Then fired after some cranking no ether. Then fired cranking, no ether, and ran for a few minutes! Getting better at it!

Next goal in life: get it to run smooth, and put into gear and drive fwd and backward! Can't wait.

I have decided on some modifications to make. But first, some pics of the recently demoused box interior. Needs very thorough cleaning, and some removal of failed plastic trim etc. I want to make the box contiguous with the cab, and install a few captains chairs in the the box. That way I can take 4 seat-belted peeps. I have three daughters and we like to go skiing. They want to make this a ski weekend mobile. A Unimogski Mobile.

 

[SuperMochombo]

 

[SuperMochombo]

Aint no sunshine when she's gone.

Just tried to bump her. No dice. I'm suddenly deflated.

I could give a darn who won the game, or what she wore. Don't care AT ALL. My world is this truck

We are all crazy. The gods must be crazy.

 

[SuperMochombo]

I have a new theory! All I did yesterday was rub the plugs a little with a wire brush, and ditto the inside of the carb. Maybe Unimogs loooooove rubbing? Maybe I just didn't rub her enough today, so she won't start for me?

I am a professional boatbuilder. I build boats out of wood, fiberglass, aluminum, carbon, etc. I know boats love to be rubbed. It's part of my job. The more you rub em the better they work. Maybe trucks are the same.

Either that or the carbs running rich rich rich and fouling everything out immediately. That's my other theory.

 

[NDT]

You need to rebuild the carb. Every single passage needs to have a wire or drill passed through. All new gaskets and wear parts. Float set to spec. Fuel system clean end to end. Get all this done. Then try to start. Tay Tay would be proud of you.

 

[BELinNC]

Hi again, I agree with NDT. That carb needs complete disassembly and cleaning. A few years ago I built a Mercedes Benz 170vk (war time kubel) replica from a post war MB170v. Nice little straight 4 with updraft carb set up. Went through that carb and had it running really nice. I sold it to a collector friend and he let it sit with regular unleaded in the system. I was helping him put on an event approx one year later and the 170vk would not run worth a crap, barely at all. Tried carb cleaner with it mounted, but no help. Had to take the carb off and strip it down which is fairly easy to do on that carb. It was totally gunked up with gas sludge. I was amazed that it got that bad in a year. Ran great once again after getting it back together. Of course non ethanol fuel would prevent that kind of issue and that is what he is using now. Trying to buy the 170vk back from him!
I hope that you might get similar results if you strip that carb down and go through it,

 

[87cr250r]

Spark plugs can't be cleaned. When they foul they get carbon tracks burned into the insulator. You might be able to clean a plug and get it to run but it won't run right. There are many habits that need to be broken.

Don't clean carburetor jets either. Running wires through them resizes the holes. Cleaned jets run rich. There are a few places that you really need to run new/known good parts until you know a bit more about how the thing runs.

 

[tennmogger]

if new plugs were required every time an M-180 fouled them it would become a very expensive truck.

 

[SuperMochombo]

Well whatever the case, my next mission is to rebuild the carb. I'm waiting to get the gasket kit. I raced Hondas in the 250 class in the 90's and those were the last carburetors I touched before this zenith. I could tune my bikes. I'll figure this out too.

I'm hoping to get this right and not be fouling plugs. But in the process I might buy a case of them

 

[SuperMochombo]

Here's the port (driver) side of the box with all the access doors for various storage etc

 

[SuperMochombo]

Great news! Got my parts! I popped the carb off, completely disassembled it, and have it soaking. The running problems are all likely due to the carburetor and the parts under the distributor cap, and collectively timing. I got a timing light, plugs, wires, etc. but first I have to get in the ball park with a running engine to time it.

I didn't see anything to report in the carb, except two things: 1) all the videos I could find about the Zenith 32 NDIX carburetor were for porshe owners, because the same carb was used in a porshe that everyone likes to rebuild. No choke on the porshe version, and we unimogs have chokes. More importantly, the ball valve seat in one of the brass pieces is bent, probably keeping the vall from fully seating. Need to further investigate the part no. and see about that.

I got a muffler and a bunch of other stuff. Plenty to work on!

I'm going to replace at least the muffler and the tailpipe. Only the muffler has failed. I bought the whole system from the header back, but I won't replace any parts that have serviceable life left in them. It's all pretty rusty. Gotta get a rust plan. Looking to paint these new exhaust parts I'm putting in. They are the real deal stamped with the mercedes logo and everything. Hate to just throw them to the dogs without some kind of protection. They are primed with some kind of dusty grey primer. Probably manufactured a long time ago in Germany. I have no idea what kind of primer this is but it is for sure not going to keep my proud new muffler from rusting. I will give them a good acetone wipedown, prime and paint em with something.

 

[SuperMochombo]

 

[dougco1]

Great news! Got my parts! I popped the carb off, completely disassembled it, and have it soaking. The running problems are all likely due to the carburetor and the parts under the distributor cap, and collectively timing. I got a timing light, plugs, wires, etc. but first I have to get in the ball park with a running engine to time it.

I didn't see anything to report in the carb, except two things: 1) all the videos I could find about the Zenith 32 NDIX carburetor were for porshe owners, because the same carb was used in a porshe that everyone likes to rebuild. No choke on the porshe version, and we unimogs have chokes. More importantly, the ball valve seat in one of the brass pieces is bent, probably keeping the vall from fully seating. Need to further investigate the part no. and see about that.

I got a muffler and a bunch of other stuff. Plenty to work on!

I'm going to replace at least the muffler and the tailpipe. Only the muffler has failed. I bought the whole system from the header back, but I won't replace any parts that have serviceable life left in them. It's all pretty rusty. Gotta get a rust plan. Looking to paint these new exhaust parts I'm putting in. They are the real deal stamped with the mercedes logo and everything. Hate to just throw them to the dogs without some kind of protection. They are primed with some kind of dusty grey primer. Probably manufactured a long time ago in Germany. I have no idea what kind of primer this is but it is for sure not going to keep my proud new muffler from rusting. I will give them a good acetone wipedown, prime and paint em with something.

A good quality high temperature off the shelf spray paint in a rattle can is all you need. I use to paint my service trucks exhaust systems back in the day. It would hold up for a several years depending how many salty roads you travel.
Rust-Oleum High Temperature Spray Paint or Krylon High Heat Max Finish are good choices.

 

[SuperMochombo]

The rust plan is rattle can.

Ugh the damaged part I noticed in the carb is the pump suction valve. I tried to repair it and really destroyed it. EI doesn't have one but maybe they know a good source. I found one at Swiss Army Vehicles and ordered it, though the shipping was unreasonably high and I don't have any experience with the company. You could shoot one out of a BB gun, or put it in an envelope. Last I checked a stamp was under a dollar.

The last guy to work on this carb didn't do so hot. The carb is a complete mess. A few double gaskets. Every slot is mangled. I have soaked and rubbed everything with various brushes and it still looks a mess. It was missing 3 of the 4 little o ring gaskets and two different washers. I spent a few hours scrubbing and polishing, but the float bowls and internals all look like coral. Back for more soaking. I'm going to have to resort to a Dremel I'm afraid.

It will be at least a week before I get the pump suction valve, so I have plenty of time to clean it up good.

There's no way Napa has this part, right? Maybe I'll just buy a whole new carburetor. I've seen some FleaBay clickbait for them.

 

[BELinNC]

That is odd damage on that part. Hard to figure how it was inflicted. Not good news to see how the screw driver slots have been abused. Seems like your description of coral is referring to corrosion in the inner bowl surfaces? Must have been a lot of water in there over the years. Not trying to tell you how to spend your money, but another carb might be the best choice. Of course see how your rebuild/refurb attempt works first!
Swiss Army vehicles has been around a long time. I got some G wagen parts from him some years ago. I think his reputation is pretty good-maybe not his shipping prices!

 

[SuperMochombo]

I think this carb is going to work like a champ. I've got it much cleaner and lapped all the gasket surfaces. Funny enough, I fixed the pump suction valve. I also have been notified by Swiss that they fed exed. And Scott from EI sent an email saying the Zenith 36 (used in Pinzgauers) uses the same pump suction valve and they do indeed have the part. So I will have one good one and one spare. Even though I got the ball to stay in the thing, I am willing to bet the valve won't seal perfectly.

Looking at the parts available out there, could probably build a whole new carb. There's an option in Turkey. I think most of what I have is serviceable, and it's a real live Zenith DB 11, the original carb that came with the truck probably.

Also painted the muffler with stovepipe paint. I figure it's a few bucks and if it gives it a little more life then great. If not I tried. I do know that paint works pretty well because I've used it for stoves a lot over the years. It doesn't protect well but it's better than nothing.

 

[SuperMochombo]

A big high five to Swiss Army Trucks. The pump suction valve was on my porch when I got home. When I opened it, the end was dented like the one in my carb was before my "repairs." So it has to be made that way, clearly to keep the valve from closing all the way. Future carb rebuilders take note.

I'm going to put it together tonight but wait till tomorrow to test it out, because I also want to get the muffler on. I'm considerate of my neighbors.

Cheers to all, happy Friday! Have a good weekend!

 

[SuperMochombo]

Muffler on, carb on, running and driving!

Well, sort of. I changed the plugs and wires, and scratched up the rotor and cap contacts. I got it to fire and run, but only by goosing the gas pedal. I set the hand throttle and it will sputter along on its own, but the rpms are pretty high.

I put it in first and second gear, drove forward and backward. First impressions: no power steering, wide turning radius, feels like a tractor, I want to drive more.

My next move is timing, and change all the fluids. Going to place an order with EI again, and get a working temp gauge. I think the oil pressure gauge is working.

I'll get a video of it running. It sounds awful, doesn't idle, smokes a lot. Not sure how much faith I have in my own carb cleaning/rebuilding. I have just begun messing with the idle screws, so maybe my problems are there. Might have to replace the jets and other assorted brass.

 

[NDT]

Sounds like overfueling. Something still not right with the carb.

 

[tennmogger]

About that poor or no idle: If you can screw each of the idle air screws all the way in, gently, and idle does not change, then most likely the idle jets have plugged. A tiny amount of crud will plug them. remove the jets and check and clean. You no doubt cleaned them but dirt shows up fast in these old trucks until the fuel system cleans up. One and a half turns CCW off 'closed' is a starting point for the idle air screws after the jets are cleaned.