Oliver under hood mufflers

BANDITFARMER

Well-known Member
Long story short I have a 1550 Utility that did have an under the hood muffler, NO One list them any ware. So I bought one for an 88 diesel and plan on making it work so hear is my question.

Now the 88 diesel is a little bit bigger in Cubic inches than the 1550 diesel but the 88 diesel runs a little slower RPMs (1800 I think) than the 1550 dose at 2000 rpm. Now that said Will the 88 diesel under hood muffler put too much back presser on a 1550 diesel? The muffler inlet is 2 3/8" but the outlet is 1 3/4" and the 1550 diesel muffler (through the hood muffler) is 2 3/8" bottom to top. I see mufflers listed for 77s 88s 770s 880s 1550 1555 all with the same muffler number for all of them so will the under hood muffler for an 88 diesel work on a 1550 diesel or not? I can increase the outlet size on the muffler if I have to but will I need to or not? The only reason I am doing this is to put the tractor back like it was new, This is one of the things that make the 1550 Utilities stand out in being different. So guys what do you think? Bandit
 
I would try it as-is first. Check out the fit, the sound, the offset between the inlet and outlet pipes, how it looks, etc. to get a baseline, then decide what modifications to make after that.
 
I have a 1550 utility, gas though. I did exactly what you are going to do, and did not increase the outlet size. I've not had any trouble with it or at least that I can tell. It looks a little weird with the smaller pipe, but it is as close to original as I can get. I figured if it worked for an 88, it'd work for the 1550. Just my thoughts.
 
That would be a good idea but no one seams to know what size the original pipe size was. Someplace I have the Oliver part number for the 1550 utility under hood muffler and its a dead number that dose not cross to anything now. I think a 2 1/2" strait pipe would be fine out of the muffler but why did the 88 diesel under hood muffler have an 1 3/4" outlet pipe?

I talk to the local Oliver dealership and they don't know ether, I did order the muffler from them. The muffler is a Stanly OL-4 same as the K452 that are listed for the 88 diesel. This is a question I have asked to a lot of people and no one seams to know if it will work or not, So I bought one to see if it will or not without being modified. I was hoping one of you guys out there who know these engines could give me some insight on muffler back pressure and if it will work or not. I sure don't know that's for sure and I didn't want to do any damage to the engine. Bandit
 
That is just what I was thinking! But one never knows these days. I have a friend that has a laser thermometer and that might be an idea way to check the muffler tempature and as well as the pipe and engine and manifold temp. With all the rain we got last night I think I have some time to play with it now. I will let you know what I find out. Thanks Bandit
 
(quoted from post at 17:20:41 07/02/14) That would be a good idea but no one seams to know what size the original pipe size was. Someplace I have the Oliver part number for the 1550 utility under hood muffler and its a dead number that dose not cross to anything now. I think a 2 1/2" strait pipe would be fine out of the muffler but why did the 88 diesel under hood muffler have an 1 3/4" outlet pipe?

I talk to the local Oliver dealership and they don't know ether, I did order the muffler from them. The muffler is a Stanly OL-4 same as the K452 that are listed for the 88 diesel. This is a question I have asked to a lot of people and no one seams to know if it will work or not, So I bought one to see if it will or not without being modified. I was hoping one of you guys out there who know these engines could give me some insight on muffler back pressure and if it will work or not. I sure don't know that's for sure and I didn't want to do any damage to the engine. Bandit
I don't think the original pipes on the 88 or 77 had a 1 3/4" outlet, I have a picture of my 77 with the original pipe and it looks to be at least 2" maybe bigger. I think these repo mufflers are wrong and will make to much back pressure for your tractor if you are going to work it.
 
Here is the picture
a161889.jpg
 
Bandit, I looked all over and couldn't find one. The outlet position on the hood will be different with the muffler you want to use. The original is offset. I will go measure the original on my 1550 for intake and exhaust. Text me and I will call you to explain. Duane
 
I'd be pretty tempted to either make a offset straight pipe, or make a offset canister that looked like the original muffler. Make the pipe 2 1/2 inch, and install one of the insert style mufflers down inside the pipe to quiet it down.
 
I just looked at my original one.The manifold has 2 inch pipe threads A small 2 inch nipple with a pipe welded around it with outside measurements just shy of 3 inches goes into manifold. Then the muffler with intake and exhaust both offset goes over it with a muffler clamp. Intake is 3 inches ID and exhaust is 2 1/2 inch. Tailpipe measured 2 1/2 ID. The muffler is about 8 1/2 inches tall and 8 inches wide. I forgot to measure the length of the tailpipe. This original setup makes the Waukesha sound very pleasant to the ear. I wish I could find mufflers for the others. If I was you, I would put the pipe thread with enlargement ring into the manifold (see parts book or call me). Have a muffler shop bend you a 3 inch pipe to offset and go thru the sheetmetal. Then I would look real hard for a Nelson muffler with a 3 inch intake. That makes them sound so much better. Duane
 
Well that is what I found out today when I took it apart. I posted pictures of it in a new thread above. I am already knee deep in it so I will be continue modifying the new one and making it fit. Thanks for the information. Bandit
 
I dug around and found a new old stock muffler that's always made me curious. Inlet diameter is 2.890, inlet height is about 1.5 at the shortest point. outlet diameter is 2.441. Outlet height is 4". Body height is right about 9", body diameter is about 7.750. Has Nelson 8V79 stamped on it. Inlet and outlet are oriented about 90 degrees apart.

I'm going to go out on a limb and say this is a 1550 utility muffler.
000_09051_zpsb86468b7.jpg
 

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