Generator Wars - The Tailpipe Strikes Back

[Mike Ellis]

Last fall a moment of stupidity removed the tailpipe from the generator in my Bigfoot 2500 10. 6. The generator is an Onan Microlite 2500. I procured a replacement tailpipe kit from Camping Country RV up in Colorado, and figured I would put it on when spring arrived.



Well, spring arrived, so I went to the mat with the generator. Sadly it put a major whuppin' on me. The major problem is that there is no room to get to the muffler outlet to attach a tailpipe clamp. The muffler outlet on this model is in fact UP INSIDE the generator frame (see diagram below).



The Bigfoot 2500 generator compartment sits right above the battery compartment, and the generator tailpipe goes straight down through a 4" round metal duct to the bottom of the camper. My hand and the tailpipe will not fit in that tiny aperture. (see pics below)





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[Mike Ellis]

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Space in the compartment is tight, and even lifting the generator up until it touches the roof of the compartment (did that today with a stack of shims) so that you can see the bottom of the generator there is still no way to clamp a tailpipe on this rascal. I guess it might be possible to do with the generator removed or with a larger access hole, but up in that duct I see no way of getting a clamp on it. Check out the picture of the muffler outlet, looking up the duct (from bottom of duct to the muffler outlet is about 13" by the way):



The muffler outlet is shifted away from the center of the duct in this picture from my wrasslin' and cussin' to get it lifted up. I was sorely disappointed to find the outlet wasn't accessible even with it up against the roof.



Now, the original tailpipe appeared to be nothing more than a slip fit over the muffler outlet, and the kit they sent me has the identical inner diameter for the piece that mounts onto the muffler. HOWEVER, they sent along a clamp for attaching it, even though the tailpipe isn't slotted (see pics).



I am confused folks, looks to me like the only way it can be installed is to slip-fit over the outlet and have it supported by the hanger at the bottom. This seems kind of cheesy, but since the tailpipe comes after the muffler there is no pressure to worry about - with some sort of gasket up there it would probably work OK. The original tailpipe had no gasket, no clamp, nothing but the slip fit. The folks at the Bigfoot dealership in Colorado have a separate generator shop install the Onans in these campers, and the fellows at that gennie shop weren't very forthcoming when I asked them about the install in the Bigfoot 2500s so I am pretty much #@$%!



What do you guys think? Is there any type of high-temp gasket that would work there? Any input would be greatly appreciated... .

 

[klenger]

Can you call the camper mfg and ask how they install it? Could you snug the clamp as far as possible without the tailpipe attached, install everything, and then attach some kind of clamp under the camper to hold it in place? Good luck.

 

[Gary - K7GLD]

How snug a fit is the new pipe into the muffler outlet?



There are some pretty good muffler sealant products, sort of like epoxy, that might be used to provide a strong seal without need for a clamp, just liberally coat the surface of the new pipe before seating it to the muffler outlet - but it sure looks like the length of that pipe would need SOME vibration support, regardless of whether a clamp could be used or not...

 

[Mike Ellis]

The tailpipes fit snugly over the outside of the muffler outlet, when it first came off I assumed it fit *inside* the outlet (notice the picture of the outlet, it looks like a "pipe within a pipe"), and that a clamp would install over the muffler outlet and squeeze it onto the tailpipe. However the muffler outlet isn't slotted to allow compression.



You are correct Gary, vibration is an issue for a pipe that long, in fact when I knocked it off I tried to "bandaid" the old hanger strap back together, and the pipe had enough side-to-side vibration to knock it loose again real quick. Before the strap was severed though, the pipe seemed OK, the gennie ran quiet and no obvious buzzing.



I called Bigfoot directly, but they don't install the generators as they are a dealer item. I called the dealer up in Colorado and they couldn't tell me much either, because they have a gennie shop install them. I called the gennie shop, and they were reticent with info - the only thing the guy would tell me is "helps to have skinny arms like an ape". I began to figure they didn't clamp any of them on, because he couldn't/wouldn't describe the clamp configuration to me.



It is certainly a head-scratcher, there's got to be a way of doing it. I'd sure like to see how they are attached on another 2500 series camper with the Onan gennie

 

[phloop]

How about gooping up the joint with high temp silicone sealer? Should be able to handle the heat and as it does not harden, it should allow some movement. And if you ever happen to have another moment of stupidity , it should come apart easier than some sort of sealer that does harden.

 

[Boomer II]

You need to get this figured out Mike in case I ever need to do mine.

 

[Mike Ellis]

I think I know how I can do it now, Mark Holmes up at Bigfoot talked to some installers for me and verified two key pieces of information for me:



1) There is supposed to be a clamp installed

2) The tailpipe that connects to the muffler outlet is supposed to be slotted



It probably seems pretty simple to you guys, but having TWO actual tailpipes in hand with no slots, and no other Bigfoot with the same setup to look at (they are pretty rare down here in Texas, other than Boomer I don't know of any others) I was and #@$%!. It seems pretty clear now that the fellow who installed the original tailpipe was just too doggone lazy to do it right.



The guys Mark talked to, are able to get their arms up in the duct far enough to wrench the clamp - they just stick it on the tailpipe, poke her up in there, and get after it. I will have to modify this approach a bit since I can't fit my beefy paw into the duct - Mark mentioned that sometimes they remove the duct so that is an option too.



I think I have the ticket right here in my toolbox. The duct is about 13 - 14" long, so if you are able to get a wrench on it with a long handle, you don't have very much arc of motion because the duct is less than 4" wide. However, for Christmas a couple years ago I received a set of those nifty ratcheting box wrenches with the fine-tooth ratchet. I checked, and it will indeed ratchet within the confines of the duct.



So, one day at lunch I'll take the pipe by the muffler store and have them slot it, then Saturday I'll dive in and take the generator on in a Texas steel duct death match - one way or another that tailpipe is gonna get connected to SOMETHING. :-laf :-laf

 

[JFaughn]

It looks like you might have enough room to block , shim it up until it hits the top of the compartment and reach under with extentions to reach clamp then lower down to finish, or use some red[ high heat ] sillycone and push pipe up and fasten pipe in place , a couple of possablities.