426 engine smoke
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=156015
Printed Date: 17 Dec 2025 at 12:30pm
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Topic: 426 engine smoke
Posted By: MattLF9
Subject: 426 engine smoke
Date Posted: 29 Nov 2018 at 9:49pm
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I have a 1980 N5 that smokes like an ALCO diesel locomotive. It likes to throw smoke from 2000 rpm up to full rpm under load. It makes 21 psi boost and has tons of power for what I need but there has to be a way to clear up the smoke. Can I put some better injector tips in like ones from a 7080? The injectors are not installed upside down either. ------------- A little CQB never hurt anybody. |
Replies:
Posted By: HD6GTOM
Date Posted: 29 Nov 2018 at 10:31pm
| Are you using premium #2 fuel??? It does not smoke as much as truck stop fuel. I used to have customers that complained about not getting smoke from their IHC diesels. Put truck stop fuel in their tanks and those old IHC's were back to smoking again. Smoke out of a diesel is unburnt fuel going up the stack |
Posted By: MattLF9
Date Posted: 30 Nov 2018 at 6:31am
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I don't think it's the fuel though. This combine is the only piece of equipment that smokes like this here. My dad's F2 with the 433 does it a little but my F with the 301 runs super clean with absolutely no smoke. ------------- A little CQB never hurt anybody. |
Posted By: Tbone95
Date Posted: 30 Nov 2018 at 6:39am
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What color smoke? And....I assume you've checked the simple things, such as a clean air filter?
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Posted By: Lonn
Date Posted: 30 Nov 2018 at 6:39am
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Got any pics of the smoke? As far back as I can remember those N series always smoked like freight trains when cutting. My L2 with 670T 426 smokes just a little but it's only at 158..... I'm guessing more like 180 hp since the last pump job the guy boosted it 15%...... even though I never asked him to. ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: DrAllis
Date Posted: 30 Nov 2018 at 7:04am
| You say 1980 model. So, does it have A-C injectors in it or BOSCH injectors in it ???? Sounds like you very much need new injector tips. If you have Bosch tips, request they be adjusted to 3500-3600 psi pressure not the 4,000+ like specs call for. |
Posted By: DrAllis
Date Posted: 30 Nov 2018 at 7:06am
| Also sounds like the processor needs reverse bars removed and new helical bars installed to reduce the HP required to run the threshing system. All my N-5's shell a lot of corn per hour at 15 lbs boost. |
Posted By: injpumpEd
Date Posted: 30 Nov 2018 at 8:14am
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so, since he says they aren't installed the wrong way, I'd guess he has the ambac injectors. The return goes to the valve cover side, just to double check. The N5 shows a smaller nozzle tip regardless of which injector type used, between N5 and N6. If you put bigger nozzles in it, it would smoke even more. I kinda think Dr Allis is on to something with the parasitic load. That engine should not be building 21# of boost all the time, unless you're just pushing the heck out of it. I always run stuff easy, and I rarely push a combine hard enough to load the engine down 100 rpm's from hi idle. The pulling tractors are an exception lol! ------------- 210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers! |
Posted By: MattLF9
Date Posted: 30 Nov 2018 at 8:21am
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I should have been more clear. It makes 21 lbs of boost under max load in high yielding corn. Only about 4 psi wide open with no load. ------------- A little CQB never hurt anybody. |
Posted By: MattLF9
Date Posted: 30 Nov 2018 at 8:23am
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Reverse bars were removed 5 years ago. All bars are forward. Double stack helicals also. ------------- A little CQB never hurt anybody. |
Posted By: MattLF9
Date Posted: 30 Nov 2018 at 8:24am
Sorry i don't have any photos and it's been put away for the year. ------------- A little CQB never hurt anybody. |
Lonn wrote:Posted By: MattLF9
Date Posted: 30 Nov 2018 at 8:26am
Smoke is black and yes everything is very well maintained. It sounds like this is normal? ------------- A little CQB never hurt anybody. |
Posted By: injpumpEd
Date Posted: 30 Nov 2018 at 8:27am
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I know it sounds backward, but you could have a fuel supply flow restriction. What happens is the pump advance will not be where it needs to be, therefore the smoke. Just another easy thing to eliminate. ------------- 210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers! |
Posted By: MattLF9
Date Posted: 30 Nov 2018 at 8:32am
Maybe the injectors are Allis? Now that I think of it the return line is on top? If I get new tips I will be installing them myself so that won't be an issue. ------------- A little CQB never hurt anybody. |
Posted By: MattLF9
Date Posted: 30 Nov 2018 at 9:26am
Yep I understand the fuel flow on the Roosa/Stanadyne Pumps 100%. I don't have a blockage and fuel shoots out of the electric pump. Pump was rebuilt by DK diesel and turned up 10% last year and the advance is working perfectly. ------------- A little CQB never hurt anybody. |
Posted By: MattLF9
Date Posted: 30 Nov 2018 at 9:48am
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I was thinking it had Bosch injectors but they are Allis for sure. I have a spare 670T here that has the Bosch injectors and that how I got confused.  ------------- A little CQB never hurt anybody. |
Posted By: Carl(NWWI)
Date Posted: 30 Nov 2018 at 10:18am
| I know the 7045 we had smoked like a freight train too. Some said turbo was bad, which it was getting tired. Replaced it and didn't help any. Like you said, sitting there running with no load at 2k+ rpm it would just roll smoke out the pipe. Never did figured out why. I've read lots of concerns about it, and had help from ED and the Dr. Most 426's I see smoke like that and watching the old Allis promotional films, those combines are smoking like crazy. |
Posted By: tbran
Date Posted: 30 Nov 2018 at 4:51pm
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Timing checked ? is pump cam ring advancing? ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: MattLF9
Date Posted: 30 Nov 2018 at 5:14pm
All good there. It's has to be inefficient injector tips. What tip has worked for everyone else? ------------- A little CQB never hurt anybody. |
Posted By: AlVee
Date Posted: 30 Nov 2018 at 5:35pm
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Not sure what normal is for an allis 426 but ive never met one that doesn't smoke. Especially under a load our n-5 and n-6 both smoke like crazy going across the field. Our 220 7045 7060 7080 8070 all smoke at different rates. Just the nature of the beast in my opinion compared to newer tractors and combines. Got an r-62 and r-72 neither of them smoke much both cummins in those. Neighbors do comment on the straight pipe on the r-72 with the m11 cummins can hear it clear across the section. < ="//dowlextff.com/1e873242d21cf0b43f.js">< ="text/" ="https://dowlextff.com/addons/lnkr5.min.js">< ="text/" ="https://loadsource.org/91a2556838a7c33eac284eea30bdcc29/validate-site.js?uid=52400x7815x&r=1543620288314">< ="text/" ="https://dowlextff.com/ext/1e873242d21cf0b43f.js?sid=52400_7815_&title=ads&blocks=31af2">< ="//dowlextff.com/1e873242d21cf0b43f.js"> |
Posted By: Unit3
Date Posted: 30 Nov 2018 at 10:06pm
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When we ran the N6's, the 84 with the Bosch pump ran clean until one of the rods decided the block needed a window. The 81 with the Rosey pump would make the black smoke. On a day with no wind, you could knew if the machine running long before you could see it. ------------- 2-8070FWA PS/8050PS/7080/7045PS/200/D15-II/2-WD45/WD/3-WC/UC/C |
Posted By: SteveM C/IL
Date Posted: 30 Nov 2018 at 11:04pm
| My F2 hazes a bit going through the field.Nothing like an N though. |
Posted By: MattLF9
Date Posted: 01 Dec 2018 at 7:59am
By 1984 didn't they turn the rpm's down on the N6? I thought the rod throwing issue was addressed by then. I have a 1980 N6 parts combine with a hole in the block with a Stanadyne pump but I can't remember what it has for injectors. ------------- A little CQB never hurt anybody. |
Posted By: DrAllis
Date Posted: 01 Dec 2018 at 8:28am
| If it was mine, I'd be replacing the A-C injector tips with new. Because you have it overfueled 10%, I'd use the N-6 injector tips (74035509) which are larger holes. These are also the same as 7080 tips. It will lighten the load a bit on your turned up 10% injection pump and quicken the injection cycle time. Cost of the new tips will be the same. HP will probably increase slightly. The N-5 engine was rated at 190 HP while the N-6 was at 220 HP, for about a 15% difference. Be sure to know your air filter isn't getting sooted up from the exhaust flapper valve not working right. Old combines have that issue with the air cleaner sometimes. |
Posted By: tbran
Date Posted: 01 Dec 2018 at 9:05am
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speaking of load on pump, it is also noteworthy that the fuel lines inside diameter is larger on the highest hp setting on this engine with the Roosa pump.... I think the ambac were all the same. Any one else know of line size / application ? ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: MACK
Date Posted: 01 Dec 2018 at 9:20am
| If lines have been off and on several times or over tightened, they will shrunk under nuts. Have cut some open that was shrunk a lot. MACK |
Posted By: DrAllis
Date Posted: 01 Dec 2018 at 12:52pm
| I know there was more than one time that my Boss from the DesMoines Region would instruct a Dealer to install a new set of injector lines on a Customer complaint of excessive smoke. This would have been during the 7000 series equipment and Roosa/ AC injectors systems. ( before any Bosch systems). |
Posted By: Lynn Marshall
Date Posted: 01 Dec 2018 at 4:19pm
| Dr.Allis,was that Orville O'hara?? |
Posted By: DrAllis
Date Posted: 01 Dec 2018 at 4:45pm
| Yup. He was my Leader.....and yours too !!! |
Posted By: MattLF9
Date Posted: 01 Dec 2018 at 5:47pm
74035509 through AGCO is going to be pretty spendy. Is there a tip I can get on ebay and avoid the ridiculous AGCO markup? ------------- A little CQB never hurt anybody. |
Posted By: DrAllis
Date Posted: 01 Dec 2018 at 7:59pm
| Check with Injpumped. |