My name is Boyd, I live in Saskatchewan, Canada. I have an ex-Swiss Army Unimog 404S 1962.
The truck came into Canada 5 years ago with 8500 kilometres on the odometer. I have now 15,000 kms.
The engine was very hard to start at first. Replace the batteries and better. Replaced to ignition system from
Expedition Imports and the unit starts just fine. Then 2 years ago the engine was halting and loss of power.
Installed new carb kit and problem solved. Also installed new fuel pump. No problem for about 2 years driving.
This past few weeks the engine is heating up very quickly. Replace the water pump and the thermostat with new.
The engine runs fine for a while but when it starts to work hard as in ploughing snow, it will overheat very quickly
and dump antifreeze out the small tube connected to the tank in the cab. This has happened twice in the last couple
of days and I just can't figure out the cause. Any suggestions out there? Thanks
1. plugged rad ? (internal)
2. stuck open thermostat ?
3. stuck closed thermostat ?
4. blocked rad ? external ?
5. no fan belt or loose ?
6. air in cooling system ? (low antifreeze levels when cold)
7. weak rad cap ?
8. bad rad hose collapsing and pinching off supply to the block ?
Does the engine seem to run out of power at higher rpm? With the comments about running poorly, I'd suspect too early (advanced) timing is causing the overheating.
As of a few days ago the Mog is running at 85-90c. When I did an oil change today I made sure the coolant was filled, fan is running and belts are tight. HELP!! Not sure how to check the timing as I heard this might cause it. Any help much appreciated! Cheers.
You CANNOT install the EI Civilian Ignition Conversion without setting the timing, especially if you installed the Ignitor. There can easily be 15-20 degrees variation in the magnetic ring placement magnets........Most of the time it is close, but if you do not check the timing more than likely it is NOT running as well as it could. Not to mention, we recommend you advance the timing from stock when running the Conversion kit.
Check the timing. If the distributor shifted, as mentioned your overheating could be timing related.
Measure the radiator change in temp. With an infrared gun measure temp at the top of the radiator. Then measure it going down the radiator in regular intervals. Cold spot in radiator....clogged tube. You should have gradual temperature reduction from top of radiator to bottom.
After a big sigh...here goes. I've read all the threads about how loss of power can result in a timing issue. Being new to mogs and learning, I have realized that what I am all of a sudden experiencing is a timing issue. Everything really runs great with her, but when I idle and climb hills she losses power. What use to be going up our hill in 4th & 5th is now barely making it in 2nd & 3rd. I've worked on my Ford 8N (1948) tractor, my KLR650 but am having a complete loss on trying to get her back up and running like she was. I don't have a timing gun and really don't want to go that route. I have heard you can mess with the timing without. Not sure if that's true or not. I have attached a few pics of the distributor and area in the hopes that someone can show me the way!! Ha. I am at my end in trying to figure out what has happened. But am willing to learn and take advice from the pros. Like you guys. She heats up fast and that's not normal. On top of the loss of power. Scott from EI has been great to get me the parts I needed and the last was a new thermostat. But alas, was not the problem. Again learning. Maybe someone can give me a visual of what I need to do to get the timing correct. Just at a loss but don't want to throw in the towel yet. Thanks for any advice in advance. Cheers, Chris
Okay so it's heating up, but not Overheating which is what I meant to say. Next thing quick and easy fix will be fuel filter. Then maybe a carb clean. Oh boy......
A timing light is helpful, but not essential for getting to the best advance setting for any given engine.
You can start with setting the static timing to spec, then simply play with it until it runs the best.
Most likely you're on the retarded side (the timing, not you) so begin by advancing it a few degrees at a time until it runs worse, or pings. Then back it off again.
If there's a vacuum advance on that engine, it could be part of the problem if it's not working correctly.
Your running old wires and old cap. The shielded wires are NOTORIOUS for grounding out.
You will spend more time and effort trying to get people to walk you thru timing your vehicle without a timing light than the $40 to go and guy a timing light! Borrow one from a neighbor? You will have to make a jumper in order to use the timing light with shielded wires.
Timing a 404 "by ear" is for people that have extensive experience and knowledge doing just that. It is NOT for a person with limited mechanical knowledge. I personally would guess I have timed and tuned 300 404's. I don't even try. It is more work, then just doing the job properly. By ear is for when you are stuck on the trail and don't have access to a timing light....in my opinion.
Bottom line....you can fight tuning your vehicle the proper way, or you can get your truck running well.
Very first thing I would do prior to any timing adjustment is loosen all of the spark plug wires in the cap. Start the truck and let it warm up at an idle. Remove one spark plug wire at a time from the cap. Does your RPM go down? Is it steady? Move to the next wire. Every wire should have a noticeable difference (decrease in RPM) when pulled out of the cap while running. If you come to a wire that doesn't change the RPM.....you have an indication of a bad wire. (Personally I prefer to do this test with a timing light by simply attaching the pickup to each wire and aiming the strobe at the hood. You will easily be able to see bad wires and or intermittent problems based upon the strobe.)
Along with the timing light, pickup a cheap infrared temp gun. With the engine running, read the temps of the spark plugs and or exhaust exit ports. A major variation indicates a problem with that cylinder.
Are you actually saying it is easier to time an M180 without a timing light?
Have you ever set a low compression M180 engine by ear? I would bet top dollar that you would be hard pressed to get within 20 degrees of spec. Yes fine adjustment is necessary usually in the range of 4-5 degrees, but a person that doesn't have a timing light, is not going to even get close without extensive trial and error.
So much faster to set to spec, then start your fine adjustment.
I've told this story before. Years ago I did a service call to a vineyard in the Sonoma valley. I was in the middle of checking the wires when the customer came up behind me. Truck was at a low idle. "That Unimog hasn't sounded that good in years....." "Really...." I replied. As I stepped aside he could see that (3-4) of the 6 spark plug wires were not attached to the cap! (Amazingly smooth on a 6 cylinder if you pick the right 2 cylinders!)
The point being, to the untrained ear, engine misses, timing issues are not that easily identified. I really think it is counter productive to encourage this in this instance. I assure you if I am called for a tech session and ask what the timing is set at......respond to me "I set it by ear" and it's going to be a short conversation until the person can actually give me a number. It is simply a waste of time not to know DEFINITIVELY what your timing is set at.
No, Scott. That's why I wrote "Yes, it's quick and easy to set the timing when using a timing light."
My point was that the result isn't necessarily the best timing possible for that engine. Even if everything was fresh and to factory spec, there are many other things that influence the performance of an engine, including the environment it is being operated in.
Obviously the factory timing is a one-size-fits-all setting, and I think that the engine would run better if it was tweaked to the best possible setting for its actual condition and where it is. Kind of how modern vehicles' computers do it automatically these days, taking air density and other factors into account.
I hate to say this and am somewhat embarrassed, but this is what I found. Started the morning with what Scott suggested on loosening the wires and running at idle. When I started to loosen I found that the very back wire giggled free off the cap. You gotta be kidding!! I looked at that thing in and out, up and down and never saw it. Reconnected and she was still running (idle) poorly. When to tighten the rest of the wires down and then the cap moved a hair to the left. In my amazement she was running better than ever before. Did all the climb and mountain tests in my area and she worked and ran better than ever! I always do a pre inspection when I get on the tractor, so now that is what I will be doing on the Mog. Lady Luck was on my side this go around!!
Glad you found the issue. if the whole cap and rotor is moving by hand, then it's not secured in the proper place and it's probably changing the timing when you are driving around.
I would recommend you get a timing light and get that rotor secured in the proper timed position for the long haul. Have fun, this is all about the learning experience!
I blew holes in a couple of pistons on a Ford straight six 300 years ago. All the wires came off the distributor cap and were bundled together on one side and the little screw that secures the cap in the right position, same loose. When I hit the brakes the weight of the wires being off center retarded the crap out of the timing, when I hit the accelerator, it advanced it.
The old 300 ran like a champ all the time though and I never heard nor felt any issues with timing. Eventually I started blowing oil out all over the place and that's when, using a timing light, I figured out what was going on. Too late though. Shortly thereafter I was left on the side of the road, in central Maine, in February late at night with a blown motor. Thankfully they were so common I got a used one for a case of Rolling Rock!
I'm glad you figured out the issues before any damage occurred. It always seems to be the little things that get you and after the fact they are so obvious which makes it frustrating.
Many people have the factory Unimog manuals (vendors like Scott over at EI have them for sale too), but I don't know anything about the Haynes manual. There used to be a good link to the Mog factory manuals online, but I think those links are dead. Maybe someone can help you out with a link, but I have the manuals if you want me to transcribe a procedure for you.
404 User Manual, Workshop Guide and more can be found online here (80MB PDF).
Page 43-44 of the User Manual goes over factory recommended procedure for timing.
Doing some digging on the interwebs I also found these texts:
Glenn’s Mercedes-Benz Repair and Tune-up Guide. (link)
Chilton's Repair and Tune-Up Guide: Mercedes Benz 1959-70. (link)
Okay. Hopefully Scott or someone can tell me what this is all about. Went to wire up the new coil and I have a green wire coming from distributor and a green wire that should be the +? from other side. See images. Whoever install the Pertronix Ingnitor (which is in the distributor) I don't think installed correctly. Am I wrong? Oh brother....
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