Farm Equipment - Valve lapping

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Valve lapping

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=209005
Printed Date: 21 Nov 2025 at 2:47am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: Valve lapping

Posted By: 3rd generation
Subject: Valve lapping
Date Posted: 20 Nov 2025 at 8:25pm

I’m sure this has been long discussed if lapping is needed. I just had hardened seats installed and valves ground. Personally I trust modern machining for a good seal. How many of you still lapped valves with hardened seats?

Replies:

Posted By: steve(ill)
Date Posted: 20 Nov 2025 at 9:24pm

always a good idea to get a finish lap.. if nothing else, to CONFIRM it is correct..

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Like them all, but love the "B"s.

Posted By: SteveM C/IL
Date Posted: 20 Nov 2025 at 10:22pm

Can't hurt? When seats and valves are ground/cut correctly it's not needed.

Posted By: DrAllis
Date Posted: 20 Nov 2025 at 11:35pm

HELL NO !! Ask yourself this: do you think GM or FORD for example take the time to "lap" valves and seats after their modern and expensive valve grinding equipment has just mass produced hundreds of cylinder heads a day ?????? NOPE.