Farm Equipment - 200 crank/camshaft backlash

200 crank/camshaft backlash

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=199962
Printed Date: 13 Nov 2024 at 3:09pm
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Topic: 200 crank/camshaft backlash

Posted By: Leon B MO
Subject: 200 crank/camshaft backlash
Date Posted: 24 Feb 2024 at 4:46pm

Complete rebuild, new sleeves, pistons, rod, main and cam bearing's. We installed a used crank gear on crank. Same part number, looks to be in very good condition. The one we took off was not. Went to put cam in and it has to be tapped into the crank gear teeth with a rubber mallet. Cam feels fine until engaged in drive gear. The idler gears for inj pump has .002 backlash, the cam has no measurable backlash. The cam gear was not changed and was running in a very scortched crank gear. With cam in the block, the crank turns over with no hard spots or to much drag. Will these 2 gears mate up and be happy together or do I need to replace cam gear/cam? Or keep looking?

Thanks

Leon B Mo

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Uncle always said "Fill the back of the shovel and the front will take care of itself".

Replies:

Posted By: tbran
Date Posted: 25 Feb 2024 at 9:00am

There has to be a reason. With so much $ at stake I would keep looking. Somethings wrong.

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When told "it's not the money,it's the principle", remember, it's always the money..

Posted By: DrAllis
Date Posted: 25 Feb 2024 at 10:58am

Are you sure there's "zero" backlash ?? Or is there some drag on the camshaft bearings making things a little tight ?????

Posted By: pirlbeck
Date Posted: 25 Feb 2024 at 12:01pm

Any chance that the main bearing bores have been "line bored" any time in the past? If not done properly or if the block was in really bad shape that can move the centerline of the crankshaft up in the block. Maybe the reason the crankshaft gear is in such bad shape is because it was assembled the last time with zero gear back lash.

Posted By: Leon B MO
Date Posted: 25 Feb 2024 at 5:22pm

A little more history. Dad bought this tractor in 82 from original owner, a good friend retired from farming. So we know the history of this one from day one. The rod bearings we took out were stamped 11-73, so we are confident this motor has not been apart, ever. The hours are probably in the 12k area, possibly many more. Tractor has not really been worked "hard" since dad bought it in 82, used it to plant, spray, pump water but no tillage.

My son used a dial indicator and had a 0. He did a gear mesh test on the cam/crank gear with gear marking paint. The pattern is very consistent, tooth to tooth, across the tooth in the same pattern all the way around both gears but still metal to metal in a small area on each tooth. Again, the crank gear we replaced looked pretty bad on about 14 teeth. Also, the thrust bearing had failed at some point. Part of it was in the pan when removed. Don't know if that may have something to do with this issue.

Doc, we did install the front cam bearing wrong the first time, driving it in crooked. Wrinkled it just a bit. Bought a 2nd new one and the cam really feels fine up until the cam gear meets crank. We had the crank in before the cam bearings so can't verify the cam in the running position. Really hate to pull the crank back out. The original front cam bearing we took out was worn pretty bad.

Our next thought was to install hyd pump and see how those gears mesh? I'm thinking cam gear failure, fatigue, wear, I don't know...Thanks

Leon B MO

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Uncle always said "Fill the back of the shovel and the front will take care of itself".

Posted By: DrAllis
Date Posted: 25 Feb 2024 at 6:14pm

I'd say if the hyd pump gear passes with the cam gear, your problem is the crankshaft gear.