MEP802A water in crankcase

[1brassjunkie]

Korgoth1,
I believe it does hydrolock, I turn the crank until it stops then go back the other way. I did this numerous times. I checked this morning and very little seeped through into the crankcase and drained out.
I'll pull the injectors and rotate the crank some more.
Daybreak,
If/when the batteries recover I'll install them and dead crank it with the muffler off and injectors out to see what results I get with the 50/50 mix and clean up accordingly.

 

[1brassjunkie]

The crankcase quit seeping the 50/50 mix and I sopped out the remaining fluid out of the exhaust port. I have found no indications of water anywhere. I pulled the injectors and they seemed fine with no rust or water. I finally got the optima batteries charged up and installed them. I tried the dead crank switch and it turns the motor but instantly "clunks" and won't turn any more. I hit the switch twice with the same result and stopped there. Something does not seem right. To recap, when I turn the crank by hand I only get about 3/4 of a rotation and it stops hard and does not budge. Can anyone tell me if that is normal or what it may indicate what's wrong inside?
Thanks

 

[kloppk]

I assume you cranked it with the injectors out?
If so my first hunch would be that the water that got in caused rust to form on the cylinder walls above where the pistons were sitting. When you rotate the crank and the piston hits the rusted section of the cylinder wall causing it come to a dead stop.
Don't crank it with the batteries until you can turn it over a few revolutions by hand or else you could cause further damage.

Could also be due to something in the cylinder causing it to stop. I repaired a gas generator last year that had the same symptom. Turned out the exhaust valve broke off the valve stem and dropped into the cylinder. Punched a hole in the piston and trashed the head.

 

[1brassjunkie]

No I didn't crank it with the injectors out. They were in.
When I had the injectors out before I could not turn the crank a full rotation.
I'm thinking of pulling the head to look further.

 

[Guyfang]

Take out the injectors first! Then try to turn it by hand.

 

[1brassjunkie]

Guyfang,
I tried that and it will only rotate about 3/4 turn. I'm going to pull the head and check out the top half.

 

[1brassjunkie]

Good to go

In my infinite wisdom today I learned the difference between a fuel injector and a fuel injector pump. What I had done previously was take out the fuel injector pumps and not the fuel injectors when I attempted to rotate the crank which did not work. When I did take them out the crank turned freely, and when I tried the dead crank I got to experience the red mist/spray. But that was a good sign. I put everything back together, cleaned it up some and fired it up. It ran fine, let it get up to temp and changed oil and filter. Added some Mystery oil to the next oil change and will run that for a few hours then possibly do another oil/filter change. Got a little black rain out of the stack but I put an oily t-shirt over it and contained most the mess. I put a 1-1/4 coupling on the exhaust stack with a flapper from the local tractor and supply and we are good to go. It's running as we speak. Thank you guys for the help it is GREATLY appreciated!!
Semper Fi
Pete

 

[Guyfang]

Pete,

Some people learn by reading. Some people learn by watching. And some people just got to pee on the electric fence. I was almost sure that you had mixed them up. Wanted to tell you that in my short post the other day, but had too many things going on at the same time. Had to make a run to the hospital, and forgot when I got back home. My fault.

It also never hurts to look at the manuals. My first experience with the "red mist" was good enough to last a lifetime. Sadly, it was not my last taste of it. I am glad it worked out right.

 

[kb3bf]

homemade exhaust flap.

I just managed to get a second MEP-802A real cheap ($411) since it was advertised as missing parts: a "Freq. Trip Switch" all the relays , one top cover, instrument panel cover, left door, and no exhaust flap. No batteries and no fluids. Just 14 hrs on the meter.
This MEP was smashed from something that fell from above and the paperwork with it listed it as a total loss.
I was going to use it for parts but it looks like I may get a functional generator after all. I hope I can get the missing door and other parts.

Thanks to a warning from Guyfang not to look near the injector holes when turning the fan by hand I was spared being showered by engine oil and water. I was able to expel water that collected in the motor, and eventually start it.

So far I made an exhaust flap. See image. I heated the aluminum in the oven (set at max temp) to soften it, and scoured the bending lines with a sharp blade before bending the edges with a set wide nose pliers (or whatever they are called).

I wonder why so many flaps are missing from the gens. Maybe they should be mounted with rivets.

 

[Guyfang]

Mostly they are missing because soldiers could not, would not, read P.S. Magazine. I will look at my stuff and find the P.S. article.

 

[kb3bf]

Guyfang,

The article from P.S. Magazine did not register with troops? Not surprisingly. If you find it I would like to see what it said.

After thinking how many MEPs may have taken in water due to missing flaps, I take back the riveting suggestion, instead the flappers should have been welded on the covers.

I started to build a Freq. Trip Switch from scratch since, after trying to contact the company that makes them resulted in no response.
I don't think they deal with the general public for single quantities.

A Texas Instruments application note on the LM2907N chip has a freq. to voltage circuit description.
Do you know if the MEP switch output remains high or low when there is no input, i.e. 60Hz?
I haven't traced a schematic for the MEP switch yet, but I will.

I am also tracing the wiring trying to find out where the magnetic sender is mounted (generator).
I did not find it in the TM, but I will look more carefully again.

I noticed there is no thread on the trip switch, probably too few are ever needed but I am wondering if it is worth starting one?

 

[Guyfang]

Just a short note, I have to run, but by magnetic sender, do you mean Magnetic Pickup? If so, its on the right side of the gen set, mounted on the flywheel bell housing. To wire plug, Be careful taking it apart, it flimsy. Will get back to you when I get home.

 

[Guyfang]

View attachment Exhaust Covers.pdfView attachment Exhaust Covers1.pdf

There are at least two articles that I know of.

What do you mean by Freq trip switch? Please use the same terminology as the manuals. That way we do not get confused.

Are you sure that the under freq switch is bad? Have you checked the Mag pickup?

The tech date on the under treq switch would not be in the military manuals. It's a pluck and chuck item, (what ever it is)

 

[kb3bf]

Hi Guyfang,

thanks for the article. I would not have imagined that the nets were responsible for snaring the flaps.

The Frequency Trip Switch is the name that's on the relay case and is the last relay to the right (facing front).

It's not a matter of thinking it is bad, I don't have one for this MEP and was not able to order it from Quantum Controls. This MEP-802A is missing all the relays and the switch in question (plus other items). After drawing the schematic from a spare one and following the Texas Instruments bulletin on the LM2907N frequency to voltage converter, I can now tell that the output FET will be ON (and draw current) when the pickup sees 60Hz. Now I need to find out which relay it drives by going over the schematics in the TM. From your experience do you what happens if this switch is not inserted?
Also I think this same switch may be used on the 400 Hz generator, since the time constants in the circuit are not on 60Hz and include 400 Hz (but I may have to recheck the math).

I will build the switch from spare parts and using a spare relay shell. I got the missing relays off Ebay.
Should I bother to post this info, and if so where? I doubt it is worth doing a new thread as I am probably the only person needing this switch.

 

[Guyfang]

Once again, time is short. Have to get my wife to her daily radiation treatments.

BUT, After trying to remember what Baldwin filter fits the 15 KW, for about 8 hours, to no avail, I went to bed. woke up at 05:30 and can now tell you it is a BALDWIN B4 filter. I can see it plain as day in my head. Look it up, and don't pay a bunch for it. I remember when we switched to BALDWIN, because Isuzu was charging too much for the filter. THEN we discovered, when the sets came from Isuzu, the filters were BALDWIN filters, coated with green paint. You do not have to be a rocket scientist to figure out what happened next! Will get back to you later.

 

[Guyfang]

Howdy,

Now I know why I could not find the freq trip switch. I was working 4 different problems last night. And its late here anyways. I can only work some of this stuff late, and I am no longer a spring chicken. Enough excuses. I opened a schematic for the MEP-002 instead of the schematic for your MEP-802! And gave you info over a 15 KW oil filter. Oh well, senior moment.



Heck yes, start a new thread, how to reverse engineer a Frequency Trip switch, for the MEP-802, or something like that. Knowledge is king, and if you don't share, then someone else will be standing there, reinventing the wheel next week! You never know who will need such a switch.

First off, You described where the freq trip switch is. Last relay looking thing on the right looking from the front. For a old generator mechanic like me, the front is always the control panel end of the set. So standing in front of the control panel, the freq trip switch is the last one on the LEFT side. Correct? In the parts manual it is listed as:NSN 5985-01-414-3218, part number 88-21091 . . ELECTRONIC SWITCH. On the schematic it should be called S-14, Crank Disconnect Switch. Is this what you are talking about? This switch is responsible for locking out the starter when the proper signal, (engine speed) is received by S-14, from the MPU, Magnetic Pick UP. So, the starter will not engage when this switch is not inserted in the socket.

You don't have to think, guess or figure out if the S-14 is used on the 400 hz set. Look in the parts manual. It will tell you if the part is used on the MEP-802 or the MEP-821, (400 hz) Are you familiar with Military parts manuals? There is something called a UOC. Usable On Code. If I am breaking new ground, tell me so. Then I will explain further about the code, where to find it and what it means. Why dont you take some pictures of the set. Perhaps we can I.D. whats missing, whats damaged.

 

[kb3bf]

Hey Guyfang,
you are not the only having senior moments. I subscribe to them on a regular basis.
Don't worry about replying when you are tied up. Nothing is urgent here.

I could use help with the TM parts info, as what I am finding in the TM is too little to go by.
Am I looking in the wrong places?

I will send a few separate replies, each one with image(s) and a major question to keep things simple.

In this one I am including an image of the two MEP-802As. The gray one to left works, but is temperamental starting. I think it still has fuel flow problems, but when I get it going, it produces power. However it is missing the upgraded fuze to the voltage regulator and I want to do that asap to both.
The second one has a good engine (after I flushed the rain water out), but it won't produce power because it is still missing all kind of parts which I am still trying to locate and ID.

For example I need V5, the DC Varistor, but where do I find that info in the manual? The TM legends/parts-listing in the schematic section says it is a Varistor DC System. I measured it on a TEK 576 curve tracer, and found out it turns on at +,- 75Volts DC. I would like to know the "real world part" number. The item itself has no markings. I tested the part from the MEP that has not been cannibalized (gray). It's a nice advantage in having two MEP to cross check them.

 

[kb3bf]

Like I said in previous replies, the second generator had water in the engine when I got it, but following what was said here, I fixed that problem.
Thanks to all the details offered in this thread. You saved me from getting a splash of oil and water in my face when I turned the fan by hand after removing the injectors. It squirted several feet in the air. Surprisingly there was little dark smoke from the exhaust when I started the engine. The meter shows only 14 hrs. Both are 1994 models.

Next phase is finding all the missing parts that were cannibalized from the second unit. All the 5 relays, S14 the Freq. Trip Switch, all diodes and varistors.
One of the switches has a broken plastic shaft, knobs were removed, CB1 and FU1 were also removed. Wires were cut and screws are missing. Since several panels were also missing due to damage, few people bid on this MEP and my winning bid was very low ($411). I was happy to get it just for parts, but it may work after all. We shall see.

We already talked about S14, which I am trying to build from scratch. When I get it working I will post the design info, in a new thread if necessary. I feel I should move all info to another thread, but after reviewing the MEP-802A threads I could not find a better one. I am still trying to figure out how to start a new one. I will go back and check for instructions again.

Need part numbers for CR1-CR4. I think they are 1N5006 ?
Need source info and part numbers for the two main front switches that have the metal shafts, and not the plastic ones (I assume they have different part numbers).
I got the 5 missing relays off ebay and replaced many rusty terminal screws with new SS.

For now I will limit my questions to the varistors, diodes and two main switches and what their part numbers are so I can purchase them.

It has been raining here for the last few days and everything is covered up, so I can't look up the switch numbers on the front panel. When things dry up I will resume searching for what else may have been cannibalized. Luckily it seems to be mostly small stuff. At least the voltage regulator is still there.

 

[Guyfang]

Morning KB,

Let's start with message 36.

I will walk you through the TM's in the near future.

Yes, the manuals are skimpy with info. Don't ever forget, the army, (I will say army, but mean military in general) HAS SEVERAL ADVANTAGES AND A DIFFERENT MINDSET THEN YOU. Can I assume you were not in the military?
They have advantages in the realm of money, and time management. Even when the army is laboring under a tight budget, a part in the supply system is paid for. And the money spent on repair parts is staggering. So parts, they have. Time management. EVERYTHING that is called a DEADLINE FAULT, (a fault that makes a piece of equipment non operational) is treated like a civilization ending problem. So the solution to such a problem is to replace the offending part NOW, and correct the deadline fault. Hence, the "Pluck and Chuck" Mentality. Who cares what characteristics the part has. Remove, toss away and plug in new part. We are golden. Mindset. "We ain't up and on line yet?" When a commander must notify his chain of command, up to and often including the department of the army, he will slit his own mother's throat to stay mission capable. Stealing a few parts from one set to fix another is no big crime. That's why your set has been raped. If I remember right, your set has damaged/missing skin, (the box that goes around the set). The army did not order extra skin when the gen sets were fielded. And few later. But not much. So when a set has damage to the skin, its non reparable and needs to go to the junkyard, or sold to someone like you. The army simply orders another gen set . When a set is declared non repairable due to cost, everyone jumps on it. Rape it to fix other gen sets. Its like tossing blood in the water. The sharks go into a frenzy.

Enough background for now.

Do upgrade the Quad system. The fuses and hardware are listed in a thread in SS, or simply use what makes you happy. BUT DO IT! Simple upgrade, saves big bucks in case of a bad volt reg destroying your main AC.

Good you have another set to system check parts that you are not sure are good, or that you have reverse engineered.

V5, where is it, what is it for. I do remember V1 to V4, they are on the back side of the load terminal board. But V5, not right off hand. Show me a picture of it.

Now, tell me if you have all the manuals:
TM 9-6115-641-10 Operators Manual
TM 9-6115-641-12LO Lube Order
TM 9-6115-641-24 Maintenance manual, Gen Set
TM 9-6115.641-24P Parts manual, Gen Set
TM 9-2815-252-24 Maintenance Manual, Gen Set
TM 9-2815-252-24P Parts Manual, Engine.

The proper part number for CR1-CR4 is IN5406, NSN: 5961-00-295-5757

 

[Guyfang]

OK, Message 37.

The info on he switches, is here in the SS. Do a search, should be several threads. One is still active I think. S-1 is available in EBAY, but cost a bunch. In the aforementioned thread, someone found them MUCH cheaper. And it was a good switch, not the blue plastic ones. And for what its worth, the blue ones do work, and normally well. They just don't last as long as the metal and plastic ones.

CB-1 is a 7.5 Amp CB, so anything that fits the hole, and is a 7.5 amp should do it. The one used in this set is very robust. Normaly NEVER goes bad.

FU-1 is also something you should be able to find easy. If it fits the hole, its good. I have always wondered why the engineers never put a CB in place of FU-1. Keeping fuses on hand was always a PITA. Fuse is a 30 amp.

Knobs are also simple to find. Is there still a Radio Shack in the States?

Do not bother with the wire clips that hold the relays and S-14 in the sockets. Thats the first part the soldiers toss out after the fan guards. The relays rest nicely in the sockets without the clips.

By varistors, I assume you mean V5? I have good part numbers for V1 to V4.

S-1 part number: 75902LV, (this should be the good switch)
Also, is there a diode on your S-1, between pin 1 and 7? Should be.