B underhood muffler
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=211178
Printed Date: 03 Oct 2026 at 9:43am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: B underhood muffler
Posted By: john2189
Subject: B underhood muffler
Date Posted: 24 May 2026 at 1:52pm
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Would it hurt anything if I were to add a 20” piece of pipe to the exhaust to keep the fumes out of my face? ------------- '41 Allis B '49 Farmall Cub |
Replies:
Posted By: steve(ill)
Date Posted: 24 May 2026 at 1:55pm
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no... extension would be OK... ------------- Like them all, but love the "B"s. |
Posted By: Cal
Date Posted: 24 May 2026 at 9:42pm
| It is very difficult to add an above pipe extension to an under hood muffle, because of the odd shape and angle of the pipe, If you want an above hood pipe why not get an above hood muffler and get the heat above the under hood area. The reason for the under hood muffler is to clear trees and branches, like when using a cutter bar. Cal in Ct |
Posted By: wjohn
Date Posted: 24 May 2026 at 10:30pm
So I have actually been wondering about this. The CA manuals/parts books show the under-hood muffler as part of the low compression, low octane intake/exhaust equipment, with the high compression gasoline equipment having the above-hood muffler. Did keeping the muffler under the hood help warm the distillate/low octane fuel in the intake more than an above-hood muffler would? Otherwise, I can't figure out why it was tied only to the low-compression option. I haven't looked back at the B parts catalog yet to see if it had a similar relation. I know the OP was asking in another thread about converting his carburetor to gasoline parts. If you want to do that, and assuming you are only running on gasoline these days, that might also be another reason to change to an above-hood muffler. ------------- 1939 B, 1940 B, 1941 WC, 1951 WD, 1952 CA, 1956 WD-45 |
Cal wrote:Posted By: wjohn
Date Posted: 24 May 2026 at 10:32pm
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Whoops - mixing up my Johns! I can't edit my post above due to the 404 error I get in the text editor. Sorry, not the same guy that was asking about B carb parts! Either way, I'm curious about the reason for the underhood muffler with the low octane equipment group. ------------- 1939 B, 1940 B, 1941 WC, 1951 WD, 1952 CA, 1956 WD-45 |
Posted By: john2189
Date Posted: 25 May 2026 at 6:00am
It had the underhood when I bought the tractor. Wasn’t hard, I smashed the pipe to fit the muffler. I read somewhere that the underhood was to keep water out of the manifold. Since the muffler goes in side the manifold, rain water would get into the manifold. ------------- '41 Allis B '49 Farmall Cub |
Posted By: Les Kerf
Date Posted: 25 May 2026 at 8:21am
That is an interesting question, I installed an underhood muffler on a Model C 30+ years ago and it most definitely added a significant amount of heat. I was happy to get rid of it
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Posted By: PaulB
Date Posted: 25 May 2026 at 9:12am
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It is easy enough to round out the underhood muffler to allow an extension to slip on. That is what I have done on my RC. Just use a large punch to start swelling it round again and follow with larger pieces of round stock. ------------- If it was fun to pull in LOW gear, I could have a John Deere. Real pullers don't have speed limits. If you can't make it GO... make it SHINY |