Exhaust on an MEP 002A ENGINE only....

[Incredilion]

Hey Folks,
I'm converting over an Onan MEP 002A Engine for use with a DC Motor that I plan to use as a DC generator, and I'm looking to find out if anyone knows how long of a pipe/etc will develop too much backpressure? I want to run the exhaust outside of my garage, to quiet it a little, but I'm trying to see if anyone else has done it, with what results?

The motor I'm using as a generator is one that I've been using for quite a while now, on my Lister 16/1. I have large forklift batteries that power my house, there are (2) of them totalling 48VDC @ 1105 AH. Kinda large, 5200 pounds, total.

The DC Motor I'm using kicks out about 125 Amps or so at 48 volts, so it charges the batteries with enough current to keep them efficient. This is all for winter power, I have about 8KW in solar & a 3KW windmill that makes power...sometimes. For the rest, like now, when the days are short, I need generation, via fossil fuels.

Anyways, I'm coverting (2) of these engines, rebuilts both, into DC charging generators. Working with a machine shop now to develop a shaft for the flywheel & a mount on one side for the motor/generator. I'll post pics when done, this will be my "high tech" motor!

Anyways, any help on the muffler/extension greatly appreciated-
Chris

 

[1800 Diesel]

You need to do a back-pressure calc based on pipe diameter and length of run. Also, determine what is allowable exhaust back pressure for the MEP2 engine. In marine installations (where we had very long exhaust runs), I've seen back pressures well over 20 inches water column (WC). I believe 4" pipe would be about 1/2" per foot of run and 2" would be at least 3/4" per foot. Those are ball park numbers and fittings, bends, etc. will increase the resistance value. I would take a guess that you could run 2" pipe at least 20-25' with no problem, but don't forget to install a high-temp flex connection to the pipe coming off the manifold and provide a "sliding" rigid support for the pipe run so you don't put excessive loads on the manifold. And check the TM to see if it has any values for exhaust back pressure limits.

While you're fabricating the pipe run, install a coupling in the low point with a petcock for condensation drainage and another coupling somewhere about halfway down the run on the top to do a back pressure check with a manometer. And obviously don't place the end of the run in a configuration that would allow rainwater to get into the pipe....

Hope that helps you out.

 

[gimpyrobb]

Six or so foot has been done, might get away with 10. Please post pics as you go, this is pretty interesting.

 

[Isaac-1]

You might also try asking over on the Smokstak site in the Onan generator section, there are a lot of people there that know a lot abou the Onan J series engines.

Ike

 

[Incredilion]

Thank you guys, very much. I'll stick with a 2 inch pipe, it won't be over maybe 4 feet long, just to get it outside.

I also want to use the cooling air & duct it to the inside of the house, probably going to use a heating & cooling guy to lay in a duct to upstairs & downstairs for me, with a shuuter valve to outside, directly, for summer or if it just doesn't work out right.....TM says it puts out someting like 1200 CF of hot air, at that rate it can turn over the heat in my 3K SF house in about a half hour or so, hey I don't mind, less wood I have to cut.

I have a large 1500 gallon water stove that I use as a radiator for the Lister, because it's water cooled. I'll make sure that there's no exhaust leaks in it to get gases into the house; put up CO detectors etc, too, by the outlet/s.

I'm pretty stoked about this thing now. initially, I was going to just mount a shaft on the flywheel & serpentine belt it to the Generator, but I started thinking about torque, and the mounts for the MEP motor being rubber, I kinda thought I might get a twisting motion out of it, and that's how we came up with the idea of mounting the generator right to a piece of steel, 3/8, maybe even half inch, and use it as a cover for the flysheel, with the new shaft coming out, and belted over to the generator. Confused?

OK, first I mount a shaft to the flywheel.
Then, using the SAE4 mount, make a plate that has a hole in the center for the shaft, and use this plate as both a cover for the flywheel & a mount for the generator, off to one side, the side w/ basically no maintenance, the starter side. Serpentine belt between them, 10 inch pulley on the drive side, 6 inch on the driven/generator side, and 180 RPM's of engine equals 3,000 RPM on the generator, making me mucho power.

Anyways, I'll post pics as I get this done, but the idea is that I have the ability to charge LARGE batteries directly, and for me, it'll give triple redundancy, as I am a Prepper, and the Lister is my No 1, both of the MEP Engines & generators are numbers 2 & 3.

Windy tonight, my windmill is making about 2700 watts right now, refilling my batts. Like it.

Again, thanks all-
Chris

 

[CNGsaves]

Curious also whether the exhaust on MEP-002a could have some sort of muffler installed if flow wasn't inhibited too much? I'm looking to use MEP-002a as backup whole house generator with interlock on my main electrical panel. Thus, would install MEP-002a on concrete pad behind house like Generac and build a sound deadening enclosure around the MEP-002a to also protect from elements.

Chris, how loud is your setup with 4 ft straightpipe?

 

[Triple Jim]

The MEP-002A has a muffler under the sheet metal cover. I've heard of units that had additional mufflers and they seemed to run fine.

 

[Nonotagain]

The military field laundry units used stainless steel flexible exhaust pipe extenders on the MEP-003A units.

They screw onto the fittings from the muffler as they have a pipe thread on them.

If I recall correctly, the length is in the 12-15 foot range.

The MEP-002 and 003 both all ready have a muffler/mufflers installed.

 

[1800 Diesel]

From what I can tell from listening to both MEP2 & MEP3 models running, the noise you're hearing is mostly from the mechanical side of the diesel engines, made louder by not being water-cooled and lacking sound enclosures (except ASK models)...The units already have a small muffler so additional muffler installation & associate costs wouldn't be advisable. We are about to build an outside "room" for my neighbor's MEP2 that will be insulated and the generator skid will also be resting on laminated tire treads bolted to either 6X6 or 4x6 treated timbers. On this (SS) site I've also seen several comments that validate the noise levels not benefiting appreciably from installing more mufflers. We will also be installing a short run of piping (& exhaust flex) to route the exhaust fumes & some noise outside of the generator house.

 

[Springerman]

Hello Nonotagain.
I just installed a MEP803a over the weekend and I was wondering where I would get the stainless steel flexible exhaust pipe extenders that you talked about?

Thanks.