MEP-003A pre-heat electrical help

[Sousakerry]

Hello,

I am working on a re-power project for a railroad museum utilizing the engines from MEP-003A gen-sets. We acquired 3 engines for near scrap price a few months ago and they are the engine only, no controls and missing a few parts here and there nothing major.

I am a machinist/designer by trade and I built my own custom flywheel and clutch housing adapters. The first engine is fitted and has had a few miles of testing and so far works great.

My current(pun intended) problem is I am trying to get the preheat system working as the engine is hard starting even at 80 degrees. Once warmed up to operating temperature it starts just fine. I did some testing and all glow pugs and the manifold heaters measure fine with an Ohm meter. I connected the wires to the batteries temporarily using a length of 12ga copper wire and after about 10 seconds the wire got hot. I do not have a proper amp meter but I wired up an amp meter of an old charging system and it runs about 30 amps.

The wiring diagram for the engine does not help very much and only shows 16ga wire going to the glow plugs. I do not see the intake manifold heater in the circuit. Can anyone here shed some light on this for me?

Here is a link to a video of the first time the machine was under it's own power as a diesel.
https://youtu.be/d1lVkZIOBnk

 

[DieselAddict]

Do you have the original glow plugs in the engine? What is the resistance of each one to ground?

 

[Guyfang]

What criteria are you using when you say that the glow plugs and manifold heater mesure fine? Are you using the TM's to compare against?

Of course the glow plugs and heaters, (Hr1-HR-6) are in the schematics. See below. It's not a terribly complicated affair. They are turned on by engaging the S1 start switch in the preheat position, whereby a relay, (in this instance K2) engages, allowing 24 volts to be applied to the heaters and glow plugs. Easy, simple and on the schematic. Your right on the wire size, but should use the right type, as you discovered, it gets HOT. Keep the wires as short as possible.

Looks like a nice rig. How much of an angle out of level is the engine? This type engine doesn't like to be inclined more than 15 degrees out of level. You get lubrication problems then.

Keep in mind, the engine also likes to be enclosed. You can get overheating problems if you do not have the engine inclosed.

View attachment Dok2.pdf

 

[jamawieb]

From the hard starting and the puffs of smoke I'm seeing in the video, you really need to get your injectors tested. Does it smoke a lot at start up? If so you probably have a leaking injector nozzle flooding the combustion chamber and that is why it's hard to start. I know a lot of people will say the 003a needs preheating before starting but with good injectors, correct IP timing and decent compression you don't need the glow plugs unless you're under 30 degrees. With everything right, the engine will start within 5 seconds and you won't have any smoke after just a few seconds.

 

[Triple Jim]

The engine is air cooled, and designed to run around 1,800 RPM. Running it slower definitely risks overheating because of the slow turning fan. I'm not saying you'll definitely have a problem, because the cooling system has extra capacity in most conditions, but you should probably monitor the engine temperature for a while.

 

[Sousakerry]

Thank you all for the quick advice.

Somewhere I had read that the glow plugs should have around 1-1.5 ohms of resistance and they all were within range, I am going from memory so my numbers may be off.

I have not measured the angle yet and It has been a concern of mine as well. The angle matches that of the original engine setup, I may have to wind up modifying the oil pan to have a deeper sump and use a different oil pump setup but for now I have 2 spare engines if this one decides to throw a rod.

The smoke you see in the video has cleared up after running for a couple of hours. These engines were decommissioned in about 2007 or so by the shipping labels, who knows how long they were on a warehouse shelf before that. All of the engines were take outs and only one had the problem of oil leaks reported. I so far have not found any serial numbers to date them.

The only engine shroud missing is the shutter unit that goes over the mufflers, since that shroud is past where the air exits the cooling fins I do not see where this will be a big problem. I will however monitor the temperatures more closely as we start to use the speeder in service. So far I have not loaded the engine anywhere near capacity. During my testing I will eventually be pulling several cars up grade and will monitor the temperature very closely. As this machine will operate over the rails and several miles from crossings in a very rural setting, by unskilled volunteers it will need to be reliable.

Eventually I will be changing the exhaust to come out the the rear of the car and will put a muffler farther down the pipe, with header tubes coming off of the exhaust ports, this should carry the heat farther away from the engine. The engine will also be housed inside an enclosed engine bay, open at the bottom.

Thanks for the schematic I had not found that one yet the one I had been using was the one at the front of the manual that was simplified and listed the wires as 16ga, this one says 12ga which makes more sense. I will have to borrow a better meter from work to do additional testing, my 25 year old radio shack autoranger is not cutting the mustard anymore.

 

[pjwest03]

For a more modernized setup you might want to consider using a glow plug timer relay. Helps prevent keeping them on too long. The associated wire size 16 or 12 is really only going to be adequate for short duration, intermittent loads.

 

[DieselAddict]

The manual calls for 30 seconds of preheat for over 50 deg F and 60 seconds if under. Prechamber diesels such as these need some preheat to kick off well. Can't get around the physics of it.

 

[pjwest03]

The other route is just a starter relay and a button. Nice and simple.

 

[Guyfang]

Thanks for the schematic I had not found that one yet the one I had been using was the one at the front of the manual that was simplified and listed the wires as 16ga, this one says 12ga which makes more sense. I will have to borrow a better meter from work to do additional testing, my 25 year old radio shack autoranger is not cutting the mustard anymore.


You can download all the manuals here in SS. The -34 manual normally has a better readable schematic and wire diagram. You can also look at the MEP-002A TM's and see if they are better readable. These book have been around a LOOOOOOOOOOOOONG time. To many times copied. Only small differences between the 002A and 003A.

I saw something like this in Sweden. We were renting an old house in the middle of nowhere. And old, old, old railroad track was behind the house. On morning the "Tug" came chugging and bellowing by the house towing several cars full of tourists. Looked kinda neat. Hope you have fun with it!

 

[Sousakerry]

Update on Glow Plugs, This past weekend I finally had a chance to get down to Clinton to work on the thing again. Pulled all the plugs out and cleaned them up with a wire wheel and they all checked about 5.1-5.3 Ohms. The plugs in the spare engine were in better shape so I cleaned them up and tested/installed them. I rewired some things and they are still pulling about 30 AMPS. I am going to run them through a solenoid off the ignition switch with 8 gauge wire going to the terminal where the two groups split off.

Now on to fuel supply problems.. I am using one of those cheap chineesium $20 electric pumps from FleeBay and so far it seems to run ok even on 24V. This is running through a fuel filter salvaged from a combine engine. The few times I have run it is through a jerry rigged maze of fittings and hose clamps. I want to scrap the Aeroquip 3000 PSI rated gold plated hoses that came with the thing and use regular old 1/4 rubber fuel line but I do not know what size or type the connectors are on the injector pump and the return line.

Any clues here on the required fittings that will save me numerous trips to the hardware/auto store?