7020 engine woes
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=123775
Printed Date: 28 Jun 2024 at 12:05am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: 7020 engine woes
Posted By: WD45Diesel57
Subject: 7020 engine woes
Date Posted: 25 May 2016 at 10:50pm
I had my 7020 on the a John Deere 15 foot disc bine yesterday all was going good until I stopped to change a knife on the hay bine I noticed a slight pop in the exhaust at an idle. Thought it was weird probably should have shut er down then, but thought it was fine kept going, did a couple more long rounds stopped at noticed the pop got louder following every pop was a whisp. When I crank it to start I noticed one cylinder has little to no compression. Any thoughts on what I should check before tear down, I did check the valve lash it was fine, please any thoughts!!
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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
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Replies:
Posted By: MACK
Date Posted: 26 May 2016 at 6:59am
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It has a push rod off. Remove valve cover, reinstall pushrod, and readjust. MACK
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Posted By: Jordan(OH)
Date Posted: 26 May 2016 at 7:03am
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Says it has no compression, and he has already checked the valves, it's got more problems than a pushrod.
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Posted By: WD45Diesel57
Date Posted: 26 May 2016 at 7:24am
I even set the valves hot like the book said, im leaning towards a bad valve or crack
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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
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Posted By: DrAllis
Date Posted: 26 May 2016 at 7:57am
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With the engine idling, you can crack loose each injector line and determine which cylinder has the problem. Keep your hands back away from the squirting fuel. You say nothing about heavy/puffing blow-by, so I assume it isn't a piston. Sounds like a valve failure.
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Posted By: tbran
Date Posted: 26 May 2016 at 8:03am
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burned an exhaust valve - has the unit ever been hot? If so possible seat issue.. Bad or stopped up tip can cause the valve failure. IF you crank it over and hear a ummm ummm whoosh out the exhaust- that is it
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When told "it's not the money,it's the principle", remember, it's always the money..
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Posted By: Leon B MO
Date Posted: 26 May 2016 at 8:19am
Sounds just like my 7020 last summer. It wound up being a bad exhaust valve. Then found a couple injecter sleeves had a slow leak. Hope you are more fortunate than I was.
Leon B
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Uncle always said "Fill the back of the shovel and the front will take care of itself".
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Posted By: WD45Diesel57
Date Posted: 26 May 2016 at 12:26pm
blow by is normal for its age, didn't increase when this happened
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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
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Posted By: Leon B MO
Date Posted: 26 May 2016 at 2:44pm
When we did ours, we took the exhaust manifold off(not a big job), then turn the engine over with the starter, making sure the injection pump is off. If it's an exhaust valve, you'll hear the hiss immediately.
Leon B
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Uncle always said "Fill the back of the shovel and the front will take care of itself".
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Posted By: WD45Diesel57
Date Posted: 02 Jun 2016 at 11:53am
well I finally bit the bullet and pulled the head on the 7020 last night and found the problem. all the pistons look good no burn marks, put the head on the bench and started to pull valves and as we discussed number two cylinder valve was burnt! the actual valve is burnt beyond grinding but the seat I think is savable or should I just get a new one installed?
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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
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Posted By: DrAllis
Date Posted: 02 Jun 2016 at 12:27pm
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You are in kind of a tough spot here. Not knowing how many hours are on the engine, I'd probably try and grind the existing seat and stick in a new valve and go with that. You potentially need to replace all six of the copper injector sleeves, and that costs money. The cylinder head might also be cracked at all those injector holes and that might mean welding the head, or finding an un-cracked head. If you choose to grind all the other valves and seats, you'll probably need all 12 valve guides at a minimum. Lots of options here.
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Posted By: tomNE
Date Posted: 02 Jun 2016 at 1:52pm
A good experienced machine shop is worth it's weight in gold for your problem. My dealer was up for spending a ton on parts but i took the head to my machine shop and for not much money, he had me back in good shape.
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AC from the start of my families farming career till the end!
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Posted By: Calvin Schmidt
Date Posted: 02 Jun 2016 at 2:53pm
Take the head to Holloways in Stratford and Murray JR. in the machine shop will take care of it. None better or fussier.
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Nothing is impossible if it is properly financed
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