7020 head
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=145910
Printed Date: 15 Aug 2025 at 12:43pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: 7020 head
Posted By: AC720Man
Subject: 7020 head
Date Posted: 28 Dec 2017 at 6:06pm
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I am about to look at a 7020,professionally rebuilt engine a few years ago. Owner says head gasket was blown, and Agco dealer said head had a crack in it. I dont have the full story yet but what is a good used head going for? ------------- 1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD |
Replies:
Posted By: DrAllis
Date Posted: 28 Dec 2017 at 6:30pm
| I'm confused. To say the engine was "professionally rebuilt", sounds to me like it wasn't done by an AGCO/Allis-Chalmers Dealership....???? So, if it's the first A-C 7020 engine this professional guy ever worked on, he isn't exactly a "professional" on that specific engine. Is the head gasket blown now?? or this is why it was repaired a few years ago?? HOW MANY HRS ARE ON THE TRACTOR ?? and how many hrs since the engine work?? Did it get pistons and sleeves and main/rod bearings ?? or did it just get a head gasket or different cylinder head ?? It's very doubtful I would ever just install a USED cylinder head on a 7020. At a minimum, it would get pressure checked and magnafluxed for cracks. They are somewhat known to crack on the head surface at the copper injector tube bore. This is especially common if the engine was ever gotten HOT !! like loose fan belts, low on coolant, etc........... |
Posted By: AC720Man
Date Posted: 28 Dec 2017 at 6:57pm
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Rebuilt by Agco dealer several years ago from my understanding. 8712 hrs on the tractor. Was over heating this summer so he took it back to Agco dealer. I will find out more later this week. ------------- 1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD |
Posted By: AC720Man
Date Posted: 28 Dec 2017 at 7:02pm
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Can a cracked head as you described be fixed? ------------- 1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD |
Posted By: Leon B MO
Date Posted: 28 Dec 2017 at 8:07pm
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My 7020 was losing a little water and had a miss. An old AC mechanic from days gone by pulled the head and found small cracks in the head that had been repaired and 2 of the injector tubes leaking under a pressure test. The head/injectors on the 7020 and 7010 are different and require special tools and knowledge. I am happy with my 7020, but I don't ask more of it than it can handle. The over heating, we had and 8050 that we fought for 3 years. It would run hot no matter what, new water pump, rad inspected, new thermostats and oil cooler redone. Finally one day on the disc, the oil cap blew off, and I found engine oil way over full. Injection pump was pumping fuel into the oil pan. Turns out the injector pump needed rebuilt, timing was floating all over the place. It does not run hot anymore. Not saying this is happening to your tractor but keep it in mind. Leon B MO ------------- Uncle always said "Fill the back of the shovel and the front will take care of itself". |
Posted By: AC720Man
Date Posted: 28 Dec 2017 at 8:20pm
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Usually on 190XT’s for example the engine oil level is increased by the hydraulic pump front seal and o-ring leaking into the front of the engine. Thus increasing the oil level in the crank case. Interesting the fuel pump causes that also. I am looking at this 7020 as a project, just trying to get some ideas of issues, cost as I move forward. When I finally see it I may walk away from it but I am excited to see it. Just trying to get some idea of cost if I should pursue it. ------------- 1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD |
Posted By: DrAllis
Date Posted: 28 Dec 2017 at 9:23pm
| Used to be a place in Chapin, Illinois that would/could repair cracks in those heads and install new copper injector sleeves. 8700 hrs is past time for a major OH if it has been a tillage tractor. |
Posted By: tbran
Date Posted: 28 Dec 2017 at 9:37pm
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Barnette head and block carothersville , mo. They forge them then weld and machine. Have not had an issue with any they rebuilt. If a copper sleeve head has been overheated, they usually crack. Also many head gaskets were blamed for electrolysis - 7020s and any engine set at max hp with wet sleeves are very prone to have this issue. ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: AC720Man
Date Posted: 29 Dec 2017 at 9:30am
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Thanks for the info everyone, I will find out more when i see it this weekend. The owner has been out of town. I only spoke to him briefly so I am anxious to get more info. The amount of hours on the machine concerns me. Hopefully he will have record of how many hours was on it when it was rebuilt. ------------- 1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD |
Posted By: AC720Man
Date Posted: 30 Dec 2017 at 11:09am
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I think i am going to pass on the 7020. Looked at it this morning. Transmission and engine has been gone thru by Agco dealer about 10 years ago. Bottom end of engine was done again this summer but they could not find a good head for it after they found cracks in the injector ports. Had 2 used heads shipped in but both were cracked. ------------- 1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD |
Posted By: injpumpEd
Date Posted: 30 Dec 2017 at 11:19am
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put an early style head on it, and change injectors over to older style, ends those copper tube head problems. ------------- 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: DougG
Date Posted: 30 Dec 2017 at 11:29am
| That's what I would co too, go with the early style lot less headaches |
Posted By: DrAllis
Date Posted: 30 Dec 2017 at 11:33am
| A welded/reconditioned head will have the thicker/updated copper tubes in it. There will only be trouble if the engine is allowed to overheat. Good maintenance and a good Operator is key to preventing an overheat situation. |
Posted By: AMB(wcIL)
Date Posted: 30 Dec 2017 at 7:37pm
| Both of the Cylinder Head places in Chapin IL have called it quits. Andy |
Posted By: Hurst
Date Posted: 01 Jan 2018 at 1:06pm
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If you can get it cheap enough, I’d put an old style head on it. Only thing I don’t know about is the intercooler hooking up to he old head. The intake manifold port should match up to the intercooler, but it would be the thermostat connections. I did this to my 7000 when it came up with cracks between the injector tubes. I would say worst case you could convert it to a 7010 and drop the intercooler, but I would have to see a 7020 again right next to my 7000 to see if the thermostat housing was the same type of mounting. Hurst ------------- 1979 Allis Chalmers 7000 5800 Hours |
Posted By: WD45Diesel57
Date Posted: 02 Jan 2018 at 7:33am
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from what I remember when I did the head on mine thermostat housing mounting holes are the same on all heads! ------------- 1-B's, 2-C, 2-CA's,2-WF, 1-WC,1-G, 3-WD's, 2-WD45, 1-RC, 1-D17 Diesel, 1-D14, 2-D15,1-D17 row crop,1-D19 gas and All Crop 40,60,66,72,90 and 100 |
Posted By: AC7060IL
Date Posted: 02 Jan 2018 at 9:42am
| What was ACs idea to change the 7020's 301 head to the copper sleeve type? Seems like AC took a step backward? |
Posted By: DougG
Date Posted: 02 Jan 2018 at 9:48am
| I think the idea was to keep heat away from injectors as the 301 was getting pushed harder for more power |
Posted By: Tim NH
Date Posted: 02 Jan 2018 at 2:39pm
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My 1976 7000 has copper sleeves. I see Alvin Martin Repair in Pa, has rebuilt heads for sale. Tim ------------- 1950 WD 1959 D14 1955 WD45 1976 7000 B 207 |
Posted By: ACjack
Date Posted: 02 Jan 2018 at 5:49pm
It was a step forward in reality. It provided a more constant temperature for the nozzles which gave a more consistent fuel density and with a more stabilized fuel temperature you got an improvement in horse power, emissions and fuel consumption relative to the HP. You'll also note that on the copper sleeved head compared to the head without the copper sleeves the water inlet passages into the head where larger. This increased the water flow into the head for the increase cooling that was needed. This also required that a different head gasket be used, it had enlarged water holes to match the copper sleeve head.
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AC7060IL wrote:Posted By: MACK
Date Posted: 02 Jan 2018 at 10:06pm
| Main reason for change to copper sleeve was lighter. Could get more on a ship without any more weight. MACK |
Posted By: Lonn
Date Posted: 03 Jan 2018 at 5:58am
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MACK is that a joke? ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: Tbone95
Date Posted: 03 Jan 2018 at 6:55am
| Copper is denser than iron. |
Posted By: Lonn
Date Posted: 03 Jan 2018 at 6:57am
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The copper is very thin. My point is why would Allis go through all the engineering costs to save a few bucks in shipping weight. ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: Tbone95
Date Posted: 03 Jan 2018 at 6:58am
| Agreed. Just throwing a fact in there, actually a fact that supports your thought. |
Posted By: DrAllis
Date Posted: 03 Jan 2018 at 7:21am
| A-C didn't invent copper injector tubes. Detroit diesels had been using them since the 1940's on the 2-cycles. If you never overheat an A-C, you'll probably never have any trouble. There are more engines out there that never had an issue than those that did. |
Posted By: Sandknob
Date Posted: 03 Jan 2018 at 7:25am
| Ive got an early 65 model 190 engine I'm getting ready to pull. Has a good head on it with rebuilt injectors. Going to drop in a M2 engine. Extra 190 engine will be for sale. |
Posted By: AC7060IL
Date Posted: 03 Jan 2018 at 11:27am
ACJack, Thank you for your explanation. Was the later 301s the only AC engine updated to copper sleeve heads? |
Posted By: SteveM C/IL
Date Posted: 03 Jan 2018 at 11:44am
| ....and who ever had a 7020 they didn't work dog crap out of? Uncle had dealer rebuild his years ago and dyno said 140 without touching pump.Beware..it was an M&W..LOL! |
Posted By: ACjack
Date Posted: 03 Jan 2018 at 11:53am
ACJack, Thank you for your explanation. Was the later 301s the only AC engine updated to copper sleeve heads?[/QUOTE All of the V12's had the copper injector sleeves and I do believe the D-3700 & D-3750 had them also. I worked in engine assembly/ repair from mid 1969 to mid 1974. From mid 74 until I left AC in December 79 I worked in QC as an inspector in those areas and my last 3 years I was the Customer Product Auditor.
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Posted By: DrAllis
Date Posted: 03 Jan 2018 at 12:04pm
| 3500-3700-3750 did not have copper sleeved cylinder heads. |
Posted By: ACjack
Date Posted: 03 Jan 2018 at 12:09pm
I knew that none of the 3500's had them but, wasn't sure about the 3700/3750's cause by the time they came out I was no longer dealing with engine builds on a regular basis. Thanks for clearing that up.
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