1928 D spark plug hole thread size and plug #?

Canadian Ken · Mar 17, 2013

What thread size is the spark plug holes in a 1928 D -serial #71371 - 6-3/4" bore block -mine are rusty, and I would like to run a tap through before installing the head
What spark plugs do guys use? I did have plugs in 2002 when I dismantled the tractor -they were two piece, but I cannot locate these now- I also moved the tractor from one shop to another since then -all other parts are still here.
Thanks in advance

Ken

LarrySTN · Mar 18, 2013

Your D should have 1/2 inch pipe thread for the spark plugs.

John T · Mar 18, 2013

The original plug was a Champion 7 and 7/8 pipe threads as posted....You may find some on Flea bay or most tractor shows have antique plug vendors....

John T

LarrySTN · Mar 18, 2013

John T, the 7/8 plug you mention was used at serial number 109944 and after, which is a 7/8 14 plug. The plug he is looking for is 1/2 inch pipe thread (serial number 30400 - 109943) . That would be todays champion 25 or autolite 3695

John T · Mar 18, 2013

MY Bad, I had 1/2 written right in front of me but typed in 7/8 by habit grrrrrrrrrrrrrrrrrr

Thanks

JT

gtx1967jewison · Mar 18, 2013

REMEMBER pipe thread is tapered! Do not go more rhan a tiny scrape with a tap or it will be oversized & your block is damaged.

Canadian Ken · Mar 19, 2013

right -thanks -i think i will just use a round steel brush instead -it is just surface rust

ken

1928 D spark plug hole thread size and plug #?

Canadian Ken

Member

LarrySTN

Member

John T

Well-known Member

LarrySTN

Member

John T

Well-known Member

gtx1967jewison

Well-known Member

Canadian Ken

Member

Similar threads