Farm Equipment - 200 valve lash adjustment?

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200 valve lash adjustment?

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=129504
Printed Date: 08 Jun 2025 at 2:37pm
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Topic: 200 valve lash adjustment?

Posted By: DIESEL
Subject: 200 valve lash adjustment?
Date Posted: 02 Oct 2016 at 5:12pm

This summer while in the hay field my 200 developed a rattle, which I assumed was an out of adjustment valve. The next day the tractor started to knock as soon as it was started, it sounded like it had a dead cylinder so we parked it.

I just removed the valve cover and found that the set screw had come loose on #3 intake and allowed the rod to lay over to the side. I pulled the pushrod out, and looked it over and everything seems fine, it's straight and not roughed up at all.

What I'm wondering now is what will keep this screw from coming loose when I adjust it to specs. I can move the screw with my fingers and it seems tight so I don't think the threads are messed up in the rocker arm. I'm no mechanic but I thought it would have a jamb nut on it.

All advice would be greatly appreciated, Thanks!

Replies:

Posted By: MACK
Date Posted: 02 Oct 2016 at 6:02pm

Replace the rocker and screw or rough the threads on screw and it might stay in place. MACK

Posted By: DrAllis
Date Posted: 02 Oct 2016 at 7:25pm

Take a 3/8" fine thread nut and hack saw it in half (top to bottom) and use it on the underside of the rocker arm for a lock. There's usually enough threads on the bottom of the adjusting screw to be able to do this. Quick, easy and effective.

Posted By: LeonR2013
Date Posted: 02 Oct 2016 at 11:54pm

Ace hardware here in town keeps thin jam nuts in stock. If you have one close to you they may have them too. If not get out your hacksaw.

Posted By: DIESEL
Date Posted: 07 Oct 2016 at 11:18pm

Thank's for the help guy's, she purrs like a kitten again.

Doc your jamb nut worked perfectly Wink

, Fastenal had just what I needed!!