426 8070 oil passage
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=186242
Printed Date: 03 Nov 2025 at 8:00am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: 426 8070 oil passage
Posted By: tbran
Subject: 426 8070 oil passage
Date Posted: 05 Feb 2022 at 9:51pm
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The main saddle was still drilled to lube the cam driven oil pump which exited in the early 210-220. An ole Ac service rep suggested plugging this at any teardown. ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Replies:
Posted By: Gregor
Date Posted: 06 Feb 2022 at 7:30am
| I don't have any good insight for you, but about 5 years ago, I overhauled my 8070 and noticed the main bearings for the top side were different and came with instructions and small round balls to plug a hole in the main saddle. I didn't want to split the tractor to drop the crank. My main bearing looked good on the top side. So I just replaced the bottom halves of the bearings and and left it alone. From memory, I think it said something about better piston cooling, but I really don't remember. |
Posted By: DrAllis
Date Posted: 06 Feb 2022 at 7:40am
| Two completely different issues. The 8000 series original design upper main bearing shells were discontinued 25 or so years ago. So, as a result, the upper main shells that are now provided need the piston cooling squirter holes plugged in the block to keep oil pressures within a specific range. You did the right thing on an in-frame OH. Just use the old upper shells. |
Posted By: CORLEWFARM
Date Posted: 06 Feb 2022 at 7:56am
| That needs to be in the knowledge section |
Posted By: tbran
Date Posted: 06 Feb 2022 at 8:58am
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I has been our experience that # 5 rod is the most susceptible to damage due to oil starvation, my buddy thinks this is part of the issue - I can't prove it but he said he never had a failure and oil pressure builds faster with the hole plugged especially after sitting a few days.. This is FYI ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: SteveM C/IL
Date Posted: 06 Feb 2022 at 12:29pm
| Any guess if Clevites bought in 2009 would have been made like OEM? That's what my 8070 got but I didn't do the work. Has 700 + hrs so I guess it is ok? #5 rod looked fine last summer when dealing with a leaking liner seal. |
Posted By: DrAllis
Date Posted: 06 Feb 2022 at 12:31pm
| He is of course talking about the old Generation #1 3000 series blocks. I've always blamed slow oil pressure build up due to the fact that both engine oil filters are empty from draining back, versus the Mark 2 engines having the oil filters unable to empty themselves when sitting around for weeks on end. |
Posted By: NEVER green
Date Posted: 06 Feb 2022 at 6:08pm
Exactly, thats why my Allis manual says to fill those filters after oil change. ------------- 2-8050 1-7080 6080 D-19 modelE & A 7040 R50 |
DrAllis wrote:Posted By: NEVER green
Date Posted: 06 Feb 2022 at 6:10pm
Steve Fisher came to the same conclusion awhile back on here. ------------- 2-8050 1-7080 6080 D-19 modelE & A 7040 R50 |
Posted By: rieg
Date Posted: 09 Feb 2022 at 8:00pm
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Hey Steve I used Clevite kits to rebuild my 8000 series 50 and 30 the bearings were exactly the same as the original, no need for plugs. ------------- rieg |
Posted By: SteveM C/IL
Date Posted: 11 Feb 2022 at 8:18pm
Thanks for that....
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