Nelson Muffler D17 IV Too Restricted?
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Category: Allis Chalmers
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=198418
Printed Date: 12 Nov 2024 at 1:52am
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Topic: Nelson Muffler D17 IV Too Restricted?
Posted By: Oldwrench
Subject: Nelson Muffler D17 IV Too Restricted?
Date Posted: 27 Nov 2023 at 7:42am
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I purchased one of the Nelson mufflers for my D17 IV several years ago when they did that production run. Loved the sound of the muffler compared to the Stanley. However, I have noticed that I have blown a manifold gasket about once a year or so. Never thought much of it, until an AC guy who knows his stuff noticed that the muffler outlet seemed smaller than what he remembers for a D17. He said that is what is blowing the manifold gaskets, with too much back pressure. This is the newer oval muffler. Now that I look at it, the outlet is about 1 1/2", while the inlet is 2". This does seem odd, to have an outlet smaller than the inlet. I looked at several on-line vendors that carry the Stanley, and it shows a 2" outlet. I'll pull the manifold this winter (for the third time) for new gaskets, and have it checked for flatness and lightly machined if necessary. Has anyone else seen this with these Nelson mufflers, or is it just me?
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Replies:
Posted By: DrAllis
Date Posted: 27 Nov 2023 at 8:13am
| Your manifold isn't flat, or pitted, or the side of the head pitted and the most likely, the nuts aren't getting retorqued every time you use it (when COLD) until the nuts quit moving. This may take several times of doing this. For the last 30 or more years, your (our) government has made asbestos a terrible thing. The gasket material they've been using since has never been as good of quality as asbestos was. That being said, I've had very good luck with the constant retorque method over the years. The D-17 outlet must have been adequate enough for 1650 rated load RPM. The 170/175 muffler is exactly the same BUT, the outlet is a little larger, I always figured to accommodate the 1800 RPM rated speed. 50+ years ago I adapted a legit Nelson 180/185 muffler onto my Dad's D-17 IV and was certain I gained HP !! When you're 16 you can tend to think like that. The way I had his tractor governor working my full open throttle plate was 1900 RPM, so I thought a bigger outlet would be helpful. Sounded cool too. |
Posted By: VaAllis1990
Date Posted: 27 Nov 2023 at 8:57am
| I agree with Dr Allis, I haven’t had a problem with mine running a new Nelson. I use high temp silicone on the gaskets as well to ensure they seal |
Posted By: Oldwrench
Date Posted: 27 Nov 2023 at 9:03am
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Doc, as always, thanks for the insights. As for the initial torque, I never used a torque wrench, since I don't know what the specs for the manifold bolts would be, although I could look up a generic chart for the stud size. For the brass nuts, I always do them "pretty tight", as opposed to "darn tight". Next time, I'll aim for "pretty darn tight" and re-tighten them several times when cool after running. I'll look carefully for any pits, and will have a machine shop check for flatness. This was an aftermarket manifold, and the casting quality was not very impressive. I use copper kote on the gaskets when installing. Meanwhile, it still seems odd to me to have an outlet smaller than the inlet. I suppose that might be part of the sound reduction. I might shop around for a 170/175 Nelson if they have a larger outlet. I've also come across some welded (no seams) oval automotive mufflers of very close to the same dimensions on the Summit Racing website, with 2" inlets and outlets and low restriction, so I might look into those at some point. I found one for $46. I'm assuming the D17 doesn't need backpressure, athough I'll re-adjust the main jet setting if I do put something different on. Anything that isn't a Stanley with its tinny sound!
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Posted By: DrAllis
Date Posted: 27 Nov 2023 at 9:34am
| No brass nuts on a D-17 engine !!! 7/16" NF size too. 3/8" nuts are WC-WD-WD45. Will have to look up proper torque when I get home, but I think like 35 ft lbs. Talk about small outlets, have you ever looked at a late model 4020 Deere with the oval muffler ?? Now, that's small for 404 cubes at 2,200 RPM !! Less noise is the reason, I'm pretty sure. |
Posted By: DSeries4
Date Posted: 27 Nov 2023 at 3:13pm
Doc, Can you explain why I can't use brass nuts on a D17 engine? Just curious about it. I have had them on mine for the last couple of years with no issues. ------------- '49 G, '54 WD45, '55 CA, '56 WD45D, '57 WD45, '58 D14, '59 D14, '60 D14, '61 D15D, '66 D15II, '66 D21II, '67 D17IV, '67 D17IVD, '67 190XTD, '73 620, '76 185, '77 175, '84 8030, '85 6080 |
DrAllis wrote:Posted By: DrAllis
Date Posted: 27 Nov 2023 at 3:55pm
| You can use whatever you want. They never came with 7/16" brass nuts that I ever remember. I've got to verify the torque tonite, as the 7/16" nuts are tighter than the 3/8" nuts. EDIT: D-17/170/175 gas manifold nut torque is 35 to 40 ft lbs. ALWAYS snug the front and rear nuts FIRST to square the manifold to the cylinder head. Then, alternate the other four nuts top-bottom-top-bottom and torque in this order. COLD torque at 35 ft lbs for the next several times you use the tractor until the nuts quit turning. That's the problem with this gasket material. It takes several times to get them smashed tight. |
Posted By: DrAllis
Date Posted: 27 Nov 2023 at 6:15pm
| I was just thinking......what is the Nelson muffler outlet diameter for a WD45 gas ?? Is it not the same diameter as a series 4 Nelson muffler ?? I'll bet it is and the first D-17's had the same muffler as a WD-45. |
Posted By: AC WD45
Date Posted: 27 Nov 2023 at 7:45pm
1 3/4". I just measured mine an hour ago for a rain cap. Looking like I need to shop for a new muffler aswell...seam split. ------------- German Shepherd dad 1957 Allis Chalmers WD45 #WD234847 1951 Allis Chalmers WD #WD88193 |
Posted By: Ed (Ont)
Date Posted: 27 Nov 2023 at 7:52pm
| Just went out and measured my WD45 muffler. It is an original Nelson that I got from an ex dealer close to me. It is 1 1/2 in outlet. |
Posted By: AC WD45
Date Posted: 27 Nov 2023 at 8:13pm
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That's strange. Mine is, as far as I know, original. They DID rebuild the tractor with a "D17 kit" in the 1970s. As I understand that bumped it up to about 53pto hp, and I have got it to crank out 52, 53, and 55hp on pto dyno at a local show. Maybe that added power necessitated a larger outlet muffler? Luke ------------- German Shepherd dad 1957 Allis Chalmers WD45 #WD234847 1951 Allis Chalmers WD #WD88193 |
Posted By: Ed (Ont)
Date Posted: 28 Nov 2023 at 7:37am
| How did you measure? 1 3/4 OD and 1 1/2" ID. Approximate. Just did it with tape measure. |
Posted By: DrAllis
Date Posted: 28 Nov 2023 at 8:52am
| WD45 and early D-17's used the SAME exact muffler. NO changes. The next muffler on the D-17 had a larger round body with the same sized outlet, to be a little quieter. Then, came the oval mufflers on series3 and 4, which were quieter yet. 170'175 got slightly larger outlet pipe, but higher up in the air to get the noise away from your ears more. |
Posted By: AC WD45
Date Posted: 28 Nov 2023 at 6:15pm
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Yup you got me. Wasn't thinking inside would be that much of a difference but it sure does! ------------- German Shepherd dad 1957 Allis Chalmers WD45 #WD234847 1951 Allis Chalmers WD #WD88193 |
Posted By: 55allis
Date Posted: 28 Nov 2023 at 11:10pm
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My brothers 45 has a Nelson but I like the sound of a Stanley, it sounds like more flow. I got a brand new Stanley for my wd and I like the sound. ------------- 1955 AC WD45 diesel with D262 repower, 1949 AC WD45 |
Posted By: SteveM C/IL
Date Posted: 29 Nov 2023 at 9:05pm
| WOW! I can't believe you said that! Each to his own..... |
Posted By: WF owner
Date Posted: 30 Nov 2023 at 6:10am
| X 2 |
Posted By: IBWD MIke
Date Posted: 30 Nov 2023 at 9:06am
Yeah, you don't hear much praise for Stanley mufflers! Have a few, they are "better than nothing", as the old saying goes!
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Posted By: JC-WI
Date Posted: 30 Nov 2023 at 9:57am
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The original Nelson was on the 170 for years, then it got a car muffler for a few years, and a straight pipe for a few years and then got a Stanley muffler for a 170 diesel (seller had listed it on fleabay for a gas 170/175) so put an adapter on to fit it and now that muffler is rusted out in the bottom after about 10 years. Got a new Nelson sitting waiting for when the engine gets OH. The Nelson feels a lot heavier than the Stanley does. ------------- He who says there is no evil has already deceived himself The truth is the truth, sugar coated or not. Trawler II says, "Remember that." |
Posted By: HudCo
Date Posted: 30 Nov 2023 at 7:32pm
| hate to say it but my wd has a stanley and its probley a little queiter at an idle than the nelson on my wd 45 and i have had to weld the outlet on the nelson |
Posted By: dfwallis
Date Posted: 30 Nov 2023 at 8:03pm
| I got a stainless steel muffler for the CA, but not installed yet. I'm guessing its China made :( |