Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo Auction Link (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Tractor Talk Discussion Forum

Spark Plug Sizes

Welcome Guest, Log in or Register
Author 
doorman

04-29-2006 20:39:59




Report to Moderator

Can anyone tell me what the thread "pitch" is on a 7/8" spark plug? I have a Wisconsin V4 engine with 18 mm. sparkplugs that have stripped out holes. I may try to tap the holes for a 7/8" plug. Anyone ever try this? Thanks in advance doorman.




[Log in to Reply]   [No Email]
Coloken

04-30-2006 00:06:17




Report to Moderator
 Re: Spark Plug Sizes in reply to doorman, 04-29-2006 20:39:59  
Years ago I did one...think it was the same as a pipe thread. Remember, pipe taps are tapered.



[Log in to Reply]  [No Email]
Bob

04-30-2006 01:03:18




Report to Moderator
 Re: Spark Plug Sizes in reply to Coloken, 04-30-2006 00:06:17  
Ken,

The 7/8" thread he is asking about is 18tpi, stright thread.

Spark plugs are also made in 1/2" and 3/4" pipe thread (tapered), but that's not what he asked about.



[Log in to Reply]  [No Email]
coloken

04-30-2006 07:07:17




Report to Moderator
 Re: Spark Plug Sizes in reply to Bob, 04-30-2006 01:03:18  
Thanks Bob, been a long time. Wasn't the model T Ford a pipe thread?



[Log in to Reply]  [No Email]
Bob

04-29-2006 22:38:38




Report to Moderator
 Re: Spark Plug Sizes in reply to doorman, 04-29-2006 20:39:59  
7/8 -18tpi is the 7/8" spark plug standard.

Heli-Coils or thread-inserts cost only a couple of bucks per hole, and then you can use the recommended spark plug.


Here is ONE source for the 18MM inserts:



[Log in to Reply]  [No Email]
Mark - IN.

04-29-2006 20:53:07




Report to Moderator
 Re: Spark Plug Sizes in reply to doorman, 04-29-2006 20:39:59  
Take the head to an engine machine shop. Let them do it in a controlled environment where they can block/lock it in place for machining. You can probably do it by hand with a lot of care, but if you mess up, it'll be more messed up and even closer to being scrap than it already might be. I wouldn't put any faith in helicoils under compression, although I've heard that it's been done. I'll bet not for long though.

Mark

[Log in to Reply]  [No Email]
[Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Copyright © 1997-2023 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy