Farm Equipment - 7080 counterbalanced crank?

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7080 counterbalanced crank?

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=27172
Printed Date: 27 Feb 2025 at 11:07am
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Topic: 7080 counterbalanced crank?

Posted By: AaronSEIA
Subject: 7080 counterbalanced crank?
Date Posted: 12 Mar 2011 at 9:27am

So, the other forum has a discussion going on the 7080 counterbalanced crank. One guy says it's the weight opposite the crank through, another says that it's in the dampener, another guy says that you can't call it counterbalanced if it doesn't have a counter rotating mass. All I can find is Swinford saying that it's counterbalanced with no explanation as to how. Parts book has no mention either. What makes the 7080 engine counterbalanced and why is it the only one of the 7000 series that is?

AaronSEIA

Replies:

Posted By: 427435
Date Posted: 12 Mar 2011 at 9:57am

Hopefully, someone with more recent experience and more intimate knowledge will post, but my memory is that the 7080 (and 7580) engine was rated at a higher RPM than the other 7000's. This probably necessitated a better balanced crankshaft.

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Mark

B10 Allis, 917 Allis, 7116 Simplicity, 7790 Simplicity Diesel,
GTH-L Simplicity

Ignorance is curable-----stupidity is not.

Posted By: niel ev
Date Posted: 12 Mar 2011 at 10:53am

Aaron the 7080 has a heavy built crank with a liquid filled balancer on the front like a N5 N6 it was the only 7000 series that used it Niel

Posted By: Steve M C/IL
Date Posted: 12 Mar 2011 at 11:14am

Been inside both but memory is so-so,soooo....my 220 has no counter weights,my 8070 has 4,2 on the ends and 2 in the middle.The 8070 is advertised as having counter balanced crank.True,but I expected to see "fully" counter balanced.Have seen big block Deeres with cranks like mine and cranks with weights on all throws.

The general consensus is that the 7080 and Gleaner engines turned too many rpms for the balance they had.Crank harmonics can cause self destruction when not "tuned" to rpm AND load.Deere guy whose word is trust worthy told me Deere had videoed inside an engine with high speed camera and the crank "moved" all over the place at speed under load.Makes you wonder how anything stays together,and we take it all for granted....Don't shoot the messenger.

Posted By: injpumpEd
Date Posted: 12 Mar 2011 at 1:51pm

there are more counterweights on rod journals 3&4. The fluid damper was also used on them. They were only used in high rpm/high HP applications.

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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: AaronSEIA
Date Posted: 12 Mar 2011 at 2:15pm

Thanks for the info. I think the guy saying that it was not counterbalanced was working on the assumption that the counterbalance needed to be some other kind of rotating weight. I think some car engines use something that rotates oppoiste the crank for balancing.

AaronSEIA

Posted By: Hurst
Date Posted: 12 Mar 2011 at 2:57pm

I think what you're thinking of is a balance shaft assembly. That's used in 4 cylinder (and manybe odd number cylinder engines? not for sure) to help balance the forces of the crank, as it is unstable in one direction.

Hurst

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1979 Allis Chalmers 7000
5800 Hours

Posted By: randy
Date Posted: 12 Mar 2011 at 5:06pm

I just checked the parts book, a 7080,8050,8070 all have different cranks and dampner. I did some checking when i had my 8070 apart, and a pulling friend said there were 2 different cranks, West German and Great britan, not sure on Great Britan, but mine had a West German crank. He said the west german would take much more hp than the other. I looked up the fluid dampner and yes it is designed for more rpm and hp. West German was stamped in the crank .

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CA WD WD45 D17 D17 Diesel 7060 8050 8070

Posted By: TexasAllis
Date Posted: 12 Mar 2011 at 6:12pm

According to Merriam Webster it is a weight that balances another

Posted By: DrAllis
Date Posted: 12 Mar 2011 at 6:21pm

Engines that have the counter-balanced crank are used in 7080-7580-N5-N6-R5-R6-8070 and 4W220. All of these also used a fluid (viscous) filled crank pulley dampner instead of the usual rubber type dampner. Don't care what the parts book says, an 8050 doesn't have a counterbalanced crank....it is in error.

Posted By: randy
Date Posted: 12 Mar 2011 at 7:55pm

Parts book says 8070 IS different than 8050

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CA WD WD45 D17 D17 Diesel 7060 8050 8070