This site is not affiliated with AGCO Inc., Duluth GA., Allis-Chalmers Co., Milwaukee, WI., or any surviving or related corporate entity. All trademarks remain the property of their respective owners. All information presented herein should be considered the result of an un-moderated public forum with no responsibility for its accuracy or usability assumed by the users and sponsors of this site or any corporate entity.
The Forum Parts and Services Unofficial Allis Store Tractor Shows Serial Numbers History
Forum Home Forum Home > Allis Chalmers > Farm Equipment
  New Posts New Posts
  FAQ FAQ  Forum Search   Events   Register Register  Login Login


Valve lapping
 Post Reply Post Reply
Author
Message
  Topic Search Topic Search  Topic Options Topic Options
3rd generation View Drop Down
Bronze Level
Bronze Level


Joined: 09 Oct 2025
Location: Iowa
Points: 8 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 3rd generation Quote  Post ReplyReply Direct Link To This Post Topic: Valve lapping
    Posted: 18 hours 29 minutes ago 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?
Back to Top
Sponsored Links


Back to Top
steve(ill) View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: illinois
Points: 88803 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 17 hours 30 minutes ago at 9:24pm
always a good idea to get a finish lap.. if nothing else, to CONFIRM it is correct..
Like them all, but love the "B"s.
Back to Top
SteveM C/IL View Drop Down
Orange Level Access
Orange Level Access


Joined: 12 Sep 2009
Location: Shelbyville IL
Points: 8694 		Post Options Post Options   Thanks (0) Thanks(0)   Quote SteveM C/IL Quote  Post ReplyReply Direct Link To This Post Posted: 16 hours 32 minutes ago at 10:22pm
Can't hurt? When seats and valves are ground/cut correctly it's not needed.
Back to Top
DrAllis View Drop Down
Orange Level Access
Orange Level Access


Joined: 12 Sep 2009
Points: 22211 		Post Options Post Options   Thanks (0) Thanks(0)   Quote DrAllis Quote  Post ReplyReply Direct Link To This Post Posted: 15 hours 19 minutes ago 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.
Back to Top
3rd generation View Drop Down
Bronze Level
Bronze Level


Joined: 09 Oct 2025
Location: Iowa
Points: 8 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 3rd generation Quote  Post ReplyReply Direct Link To This Post Posted: 10 hours 2 minutes ago at 4:52am
Bluing would confirm a fit. I do think it’s a method appropriate many years ago and has stuck in the minds of some. My search has yet to convince me it’s needed. The hardened seats will do more for longevity than any lapping could provide.
Back to Top
Les Kerf View Drop Down
Orange Level
Orange Level


Joined: 08 May 2020
Location: Idaho
Points: 1449 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Les Kerf Quote  Post ReplyReply Direct Link To This Post Posted: 7 hours 34 minutes ago at 7:20am
When Grandson and I used my 100 year old Van Norman valve grinder and my Chinese-made seat cutters from Amazon to do a valve job on Mr Cato's Model C Allis-Chalmers head with the sloppy valve guides and cast seats, why yes, we most certainly felt it appropriate to hand lap the valves. Tongue


Edited by Les Kerf - 7 hours 32 minutes ago at 7:22am
Back to Top
AC7060IL View Drop Down
Orange Level
Orange Level
Avatar

Joined: 19 Aug 2012
Location: central IL
Points: 3587 		Post Options Post Options   Thanks (0) Thanks(0)   Quote AC7060IL Quote  Post ReplyReply Direct Link To This Post Posted: 2 hours 52 minutes ago at 12:02pm
You could easily have it vacuum tested to expose any possible valve/seat fit leaks.
Back to Top
steve(ill) View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: illinois
Points: 88803 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 2 hours 24 minutes ago at 12:30pm
lapping it for 30 seconds would give you an idea of the seat and verify that all is well.. Just a quick test.
Like them all, but love the "B"s.
Back to Top
Les Kerf View Drop Down
Orange Level
Orange Level


Joined: 08 May 2020
Location: Idaho
Points: 1449 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Les Kerf Quote  Post ReplyReply Direct Link To This Post Posted: 18 minutes ago at 2:36pm
Originally posted by DrAllis DrAllis wrote:

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.

Lapping valves after having been done correctly on modern equipment does no good and may reduce longevity by a small amount.

I do not own such modern equipment Big smile

It would be difficult to prove the difference on a vintage Allis-Chalmers tractor.
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 11.10
Copyright ©2001-2017 Web Wiz Ltd.

This page was generated in 0.098 seconds.


Help Support the
Unofficial Allis Forum