C-120 Muffler Help

[Clarkbug 0]

Hello All.

So after a long drought, Im finally able to tinker with the horse again a little bit. I bought an OEM muffler from a member here, and it was off of a C-120 auto. I finally managed to get the monstrosity cob-job that was my existing exhaust off, and I am attempting to fit the "new" one on there. However, something just isnt right. The muffler body sits way to close to the engine, and the angles are all screwy.

Can someone take a few pictures of how the muffler is supposed to mount up to a C-120? Im specifically wondering about what goes on near the engine, and where the exhaust should exit. Im thinking that I need another elbow in there, but a picture is worth a thousand trips to the parts store.

Thanks in advance!

[gwgdog66 23]

I could have sworn I had some pics. It will be next weekend before I can take some more. What year is your C-120? the 74 & 75's used a muffler with and additional elbow. The early 80's used a muffler did away with the additional elbow, and had a longer pipe with the turns already in it.

[privateer 1]

i have a 74 c120. i'll post a pic later for ya....

[Clarkbug 0]

Thanks for the quick replies guys. I want to say its a '75 or a '76. The only pipe that is there is a small stub threaded into the engine block, so Im guessing its the earlier style.

So is that elbow 1"? 1 1/4"? Is that something that a local NAPA might have? Im just not sure where to pick up an elbow that small...

[rueger-99 0]

Here's a pic of mine. It's a 1976 c-120/8. Pipe size is 1".

[rmaynard 15,294]

On my 1977 B-100's with K241S engines, which have the same block as the K301S, the original pipe coming off the block is straight 1" x 2-1/2" black iron, with no elbows. All of the bends necessary are in the inlet pipe of the muffler.

The OEM muffler is a 105915/106918.

All elbows and angles are in the inlet tube:

The bracket on the bottom of the muffler is not used except on shaker cradle models.

There is at least 1" clearance between muffler and fuel lines. I have about 1/2" to 1" clearance between the muffler body and the upright of the hood. There is about 1/4" between the air filter cover and the muffler.

Hope this helps.

[mavfreak 11]

Here's a pic of mine. It's a 1976 c-120/8. Pipe size is 1".

I have to ask, was there a bit of fire going on there?

[Retired Wrencher 5,328]

Here's a pic of mine. It's a 1976 c-120/8. Pipe size is 1".

I have to ask, was there a bit of fire going on there?

I have to Agree with Heath some thing is funky with that engine {like a fire ??? how about a new air cleaner???} Gary B.............

[rueger-99 0]

Just a small fire....I'm working on it.

[Clarkbug 0]

Thanks for the replies everyone!

It would appear that I dont have an original OEM muffler, but just one made by Nelson. It looks exactly like the one Reuger posted above. So I guess I need to go find some more fittings somewhere!

Bob, thanks for the pics of your routing, it gives me something to shoot for.

Is 1" exhaust pipe a common thing to find?

[privateer 1]

[CTPATRIOT 12]

Are the factory C-120 mufflers still available new?

[rmaynard 15,294]

Are the factory C-120 mufflers still available new?

Yes. They are about $150.00. :thumbs:

[can whlvr 993]

yes 1 inch npt is very coomon and can be purchased at most hardware stores,plumbing supply stores,heating supply,tsc,and many other sources,u can usually buy the small pipe peices(nipples)from a closed nipple about 1 inch to 6 inches in 1/2 increments,and then you have to have a peice of pipe threaded and fittings that u need also should be very easy to obtain

[Clarkbug 0]

I was hoping to try and find the 1" exhaust tubing instead of NPT, only because the nipple threaded into the block now only has threads on one end of it... If I go back and try to put pipe fittings on to get me "around the bend" so to speak, I just have to get the old one out of the block.

I havent tried it yet, so it may be OK, but it always makes me nervous trying to do something like that....

But its probably my only option at this point, as I cant find 1" tubing anywhere....

[Kelly 1,029]

I believe you have a early style but orig. muffler, I bet 90%+ of the GT mufflers were built by Nelson, I have a few of the early mufflers, they fit both the big and small block Kohlers with a different fitting attached to them.

[Clarkbug 0]

Thanks Kelly.

Looking at some of the parts lists, I see that it does look like an original muffler, just that they made two different style for the C-120. Im wondering if there was a different block for some years/models?

[can whlvr 993]

i too had a hard time finding 1 inch tube and someone with a bender that could accomadate the tube,i ended up welding the old muffler for now,but thats just a band aid,good luck on the extraction of the nipple,do you have enough room to put a hand held pipe threader on the nipple and cut a few more threads?

[Clarkbug 0]

Unfortunately I dont have a hand held pipe threader to even see what kind of clearance I need.

Ill put some Kroil on the threads tonight, and maybe put some heat to it to help with the threads loosening. I also have a pretty big pipe wrench, but I just dont want to break something....

[Kelly 1,029]

There is a thread here someplace about getting the nipples out if it will not turn out, it goes something like cut the pipe off about 1/2" from block, then use a hacksaw blade to cut the pipe in half cut down till you hit the threads, do this in one or two spots, then use a chisle or punch to push the pipe in away from the threads then it should come out, not sure if I said that very well, but there is a thread on here about it, I've never had to, I heat the pipe up with a torch and take them out, had to work at a few but they all came out, now I bought a tractor from a guy that just had to have the new $10 TSC muffler and right before I got there he pulled it and the pipe, and broke the block doing it, we took more off the price of the tractor than the cheap muffler he saved.

[Clarkbug 0]

I know exactly what you mean Kelly. I have had to do that to get an exhaust pipe out of a cast manifold on a Farmall tractor.

Pretty much you cut into the pipe so you can collapse it inward rather than try to screw it out. it makes me nervous when I am dealing with the pipe on the block due to the possibility of metal shavings going into the block, but I guess with enough rags and patience, it shouldnt be a problem.

Thanks for the ideas!

[can whlvr 993]

so the other option is to get a muffler that uses the muffler clamp to the nipple,could be cheaper than breaking something,jmo

[Clarkbug 0]

Hooray!

I managed to get the old pipe nipple out of the block without breaking anything. At first I just started to crush the pipe, which was not good. I swore a little, and then went and got a bigger pipe wrench. After a liberal application of Kroil, some hammer tapping, and finger crossing, it popped and turned right out.

Now I can thread a new nipple in there thats threaded on both ends (with never seize on it!) and put a 45 elbow. Looks like its 2" off the block, elbow, and another 2" before the actual muffler piping starts.

Thanks for all the help everyone! Ill post some pics when I finally get it back up and running!

[can whlvr 993]

good to here that it worked out :thumbs:

[6wheeler 598]

Clarkbug, I hope my e-mail pics worked for you. Mine is a 76 so they should be the same configuration. Also, I found out the bottom bracket is not needed for our application. And, if you are going to use never sieze on your nipple, make sure it is the copper kind. The regular silver kind will burn to a crisp on your block. Good Luck. Pat