Generator Exhaust

Topic: Generator Exhaust (Read 1220 times) previous topic - next topic

Generator Exhaust

July 09, 2019, 12:04:58 pm

The exhaust on our generator is broken in half up by the manifold and I'm not sure how to go about fixing it. It looks like part of the exhaust is made from plumbing pipe that's been attached to the manifold and flex pipe some how. I'm wondering if this setup is normal and how might be the best way to fix it would be.

Thanks in advance, guys.

Re: Generator Exhaust

Reply #1 – July 09, 2019, 12:52:30 pm

Tyler, you have a broken nipple, a 90 elbow and another nipple which is screwed in. Simply unscrew the good nipple, take it to a store, hardware, NAPA or other, and replace.

Liberal application of penetrating fluid on the nipple is recommended. One half acetone and one half ATF, tranny fluid, is the very best fluid but store bought helps a bunch. Soaking the area with penetrating fluid for some hours or over night may be needed.

Use as big pipe wrench as you can get in there for maximum leverage. A pipe wrench will grip the nipple best. I'll bet you will need a bunch of leverage.

Remove the broken nipple from the flex and slip the flex onto the new nipple and clamp. You are done. (Boy was this easy to write, sure glad I am not suppling the muscle power)

Re: Generator Exhaust

Reply #2 – July 09, 2019, 01:06:21 pm

Suggest you replace the 90 and nipple as posted above and then install a new flex pipe as seen here: Dynomax 46972 Flexible Exhaust Pipe | eBay
I would support the flex so it would stay well away from the insulation and in several spots. Might think about installing backerboard to make the compartment much more fire resistive.

You dodged a bullet with the open exhaust close to the super flammable black insulation. Our flex had come loose and burned through the insulation to the wood. The whole thing is a poor design and if you looked at my photos of the burn test on the insulation, you can see an open flame starting a fire in the compartment would quickly spread to the rest of the coach.

Pierce

Re: Generator Exhaust

Reply #3 – July 09, 2019, 01:44:14 pm

Quote from: Rudy – July 09, 2019, 12:52:30 pm

Tyler, you have a broken nipple, a 90 elbow and another nipple which is screwed in. Simply unscrew the good nipple, take it to a store, hardware, NAPA or other, and replace.

Liberal application of penetrating fluid on the nipple is recommended. One half acetone and one half ATF, tranny fluid, is the very best fluid but store bought helps a bunch. Soaking the area with penetrating fluid for some hours or over night may be needed.

Use as big pipe wrench as you can get in there for maximum leverage. A pipe wrench will grip the nipple best. I'll bet you will need a bunch of leverage.

Remove the broken nipple from the flex and slip the flex onto the new nipple and clamp. You are done. (Boy was this easy to write, sure glad I am not suppling the muscle power)

Thanks, Rudy!
Is it just a close nipple with a clamp around the flex to hold it on there? That seems simple enough if that's the case. Is the clamp a simple u-bolt design type? There isn't any type of clamp that I can see but want to get the correct type.

Do you mix the ATF and acetone together and then put it on? I haven't heard of that combination but am interested in trying it out!

Re: Generator Exhaust

Reply #4 – July 09, 2019, 01:58:28 pm

Quote from: Pierce & Gaylie Stewart – July 09, 2019, 01:06:21 pm

Suggest you replace the 90 and nipple as posted above and then install a new flex pipe as seen here: Dynomax 46972 Flexible Exhaust Pipe | eBay
I would support the flex so it would stay well away from the insulation and in several spots. Might think about installing backerboard to make the compartment much more fire resistive.

You dodged a bullet with the open exhaust close to the super flammable black insulation. Our flex had come loose and burned through the insulation to the wood. The whole thing is a poor design and if you looked at my photos of the burn test on the insulation, you can see an open flame starting a fire in the compartment would quickly spread to the rest of the coach.

Pierce

Thanks, Pierce!
I would like to replace all of the flex if possible, it seems like a tight fit behind the generator though. The backer board sounds like a good addition, especially if the insulation is flammable! I wouldn't have thought the insulation would be flammable. Were you able to do the flex and backer board without removing the generator?

Re: Generator Exhaust

Reply #5 – July 09, 2019, 03:09:30 pm

The first thing we did was line the fridge compartment walls, floor, ceiling with Backerboard. The wood below the outside access had dryrot so it was replaced. The Romex was poorly done, suprising since Foretravel does a good job with the 12V wiring. Anyway, it was tidied up and the 110V outlets were replaced as they are right by the cover and were a little corroded. The fridge compartment is a tinderbox just waiting for some hydrogen to catch fire. No black insulation but lots of thin laun wood that will easily catch fire. An older post shows a Halon extinguisher that didn't put the fire out and the coach was badly damaged.

The engine compartment was next, especially after I tested the insulation with a match. I used R-19 Fiberglas and put Backerboard on top with stainless screws and washers on the top and sides. This won't stop a fire but will give you time to get out and possibly try and put it out and or call the fire department before the fire reaches the back.

Since we don't use our generator, I have not lined the compartment yet. Our flex came loose and melted through the insulation into the wood. To do an nice job, I would remove the generator as it's in the way. Backerboard here will not eliminate the fire risk but will slow it's progression into the rest of the coach. Diesel on the hot manifold is not that high of a risk as they are on opposite sides of the generator engine.

As a retired firefighter, I've seen lots of fires including RVs. It only takes a second of direct exposure to flame to cause a fatal burn. I've had the unfortunate occasion to step on a body in a building being consumed by fire so that's one of the reasons why I don't trust RV construction/electrical any further than I could throw it.

Backerboard can be installed with only simple tools and scored and bent to make a cut. No sawing is required with all the dust. See these videos for Backerboard water and fire tests: https://www.youtube.com/results?search_query=backerboard+fire+test

I can repost the fridge installation if you need it or just PM for the photos.

Photos attached of the insulation fire test and the flex where it melted through the insulation.

Pierce

Re: Generator Exhaust

Reply #6 – July 09, 2019, 04:14:50 pm

Quote

ou dodged a bullet with the open exhaust close to the super flammable black insulation.

On some models Foretravel attatched a piece of sheet metal between the wrapped exhaust pipe and the black insulation. Might be another way to go if you don't want a big project.
jor

Re: Generator Exhaust

Reply #7 – July 09, 2019, 06:11:30 pm

My best guess from looking at the picture is that the flex pipe which appears to be stainless steel is that it was welded to the nipple. It is possible that the flex was clamped to the nipple. What is left of the nipple looks to be almost impossible to remove from the elbow. You may have to start from scratch at the exhaust manifold and replace all of it, except for the flex pipe. Elbows and nipples are not very expensive and easy to put together, but difficult to take apart when well rusted like in the picture. If you can unbolt the elbow part from the manifold, a machine shop should be able to duplicate it and tell you if the flex was welded to the nipple.

Re: Generator Exhaust

Reply #8 – July 09, 2019, 07:19:59 pm

If you can remove the ninety, just duplicate the parts, buy a new flex, have it welded or brazed to a nipple, use a union and reassemble. You could use the old flex if it's in good shape but new is inexpensive. You want to support the flex so it does not vibrate much as stainless work hardens and will crack. Bad motor mounts may have brought on your trouble. Mounts have to be inspected underneath as the top may look fine. Make sure to wrap the flex. You can buy a roll of wrap online.

Soak with your favorite homemade or parts store penetrating fluid several times the day before.

Pierce

Re: Generator Exhaust

Reply #9 – July 09, 2019, 08:34:54 pm

Hannah and Tyler,
You are better off removing the elbow with the flange that is bolted to the back of the generator. There are 4 studs holding the flange to the exhaust manifold on the back of the generator. The nuts are either bronze or brass and will come off easily, then you can take the flange into your work area and work on removing the broken nipple a lot better. You may need to spray the assembly with PB Blaster to help loosen it. You may need a torch to heat the assembly. Attached is a picture of the flange when I removed it from my generator when I pulled the engine. There is a heat shield over the exhaust flange. You will need to remove it to get to the flange.
John M.

Re: Generator Exhaust

Reply #10 – July 09, 2019, 08:59:05 pm

Hannah and Tyler,
In the attached picture is the heat shield Jor was talking about. It blocks the exhaust flex tubing from the insulation.
John M.

Re: Generator Exhaust

Reply #11 – July 11, 2019, 09:29:08 pm

The family left for Oklahoma this morning so I was finally able able to make some progress today. Got the muffler off and the flex pulled through the floor and got the piece unbolted from the exhaust manifold. The muffler has several holes in it and flex is welded at that end as well so I'll be replacing it in the process.

The radiator was plugged full and was causing the generator to overheat and shut itself off so I got it pulled and cleaned out too. With the way the generator fits in the compartment, the radiator is a real pain to get out. I had to split the shroud and remove the fan which turned out to be a good thing. The tips of the radiator fan are damaged from coming into contact with the shroud. Got the shroud adjusted and the blades are no longer rubbing. The fan belt was real loose too so I got that tightened up.

Now to get the new flex ordered and figure out what to do about a muffler.

Re: Generator Exhaust

Reply #12 – July 11, 2019, 09:32:43 pm

A couple more pics

Re: Generator Exhaust

Reply #13 – July 11, 2019, 10:45:02 pm

Quote from: John Morales – July 09, 2019, 08:34:54 pm

Hannah and Tyler,
You are better off removing the elbow with the flange that is bolted to the back of the generator. There are 4 studs holding the flange to the exhaust manifold on the back of the generator. The nuts are either bronze or brass and will come off easily, then you can take the flange into your work area and work on removing the broken nipple a lot better. You may need to spray the assembly with PB Blaster to help loosen it. You may need a torch to heat the assembly. Attached is a picture of the flange when I removed it from my generator when I pulled the engine. There is a heat shield over the exhaust flange. You will need to remove it to get to the flange.
John M.

The four bolts came out easily after 15 minutes with some PB blaster on them. Ours didn't have a heat shield to remove, so they were easy to get to also. There was some red gasket-maker in between the two mating surfaces that needed cleaned off with a roloc disc. It didn't appear to be a high temp type but seemed to be holding up well.

I've still got to locate a bench vise in order to break that 90 loose. Hopefully we won't need a torch!

Thanks!

Re: Generator Exhaust

Reply #14 – July 12, 2019, 12:16:52 am

Being red, it was most likely high temp gasket maker.

Re: Generator Exhaust

Reply #15 – July 29, 2019, 01:01:07 pm

Got the exhaust finished up and we're pretty happy with the way it turned out. Thanks to my cousin doing the welding and Hannah helping it went pretty smooth. Had to reroute the flex but the new system is much higher and more tucked out of the way than the previous one.

Re: Generator Exhaust

Reply #16 – July 29, 2019, 01:02:43 pm

Couple more pics

Re: Generator Exhaust

Reply #17 – July 29, 2019, 01:04:08 pm

And the finished results.

Re: Generator Exhaust

Reply #18 – July 29, 2019, 01:20:00 pm

The generator needs new motor mounts something terrible. Does anyone know what was used for motor mounts? I discovered several small things that need to be repaired but the motor mounts I am unsure of how to replace.

Re: Generator Exhaust

Reply #19 – July 29, 2019, 02:14:59 pm

Will try and lookup where I got mine but one way to replace them is one at a time,unbolt the old one and bolt the new one in,the part numbers are on the old ones.

Re: Generator Exhaust

Reply #20 – July 29, 2019, 02:44:46 pm

Looks great! Quality job. So, how is it for noise? Compared to stock?

Check the archives for the motor mount part numbers and sources. There are two different manufactures so should be easy to just order four online.

Pierce

Re: Generator Exhaust

Reply #21 – July 29, 2019, 04:02:38 pm

Thanks! I will try and get one of the mounts off and see what is on it for a part number. I will also see what I can find on the forum.

As for the noise, the new muffler may be slightly louder that the old one was. It's difficult to tell though because the other one was full of holes and we really didn't use the generator enough to get a good feel for the db level. One thing that made a significant difference was adding rubber between the hangers that I made for the muffler and the beam that it was bolted to. The vibration was really bad, but adding some thick pieces of rubber on either side took all the vibration out.

Re: Generator Exhaust

Reply #22 – July 29, 2019, 04:08:11 pm

Good work.. Darn big improvement including the radiator.

Re: Generator Exhaust

Reply #23 – July 29, 2019, 09:39:57 pm

Quote from: The Soft Boulders – July 29, 2019, 04:02:38 pm

Thanks! I will try and get one of the mounts off and see what is on it for a part number. I will also see what I can find on the forum.

Generator Isolator Mount

LORD #283P-155 Powertech Generator Plate vibration mount

Re: Generator Exhaust

Reply #24 – July 30, 2019, 11:21:06 pm

Hannah and Tyler, Like the hammer in the first pic. Three basic tools: hammer, screw driver, and pliers. If the hammer is big enough then you don't need the other two.

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