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BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6507 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Oil filler thread size
Posted by: BlownMGB-V8
Date: September 10, 2024 05:16PM

Anyone know the actual thread size and pitch of the opening in the Rover valve cover for the oil fill plug/flame arrestor/etc? I make it to be about 41.75mm and about a 2.25mm pitch but that is nowhere near a standard size.

Jim


MGBV8
Carl Floyd
Kingsport, TN
(4559 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: Oil filler thread size
Posted by: MGBV8
Date: September 11, 2024 12:28PM

No, but I can bring an oil filler plug to Townsend if it will help.


Roverbeam
Chad McNeely
N.E. MO
(78 posts)

Registered:
06/09/2021 06:03PM

Main British Car:
Alpine S4 Rover 4.0

Re: Oil filler thread size
Posted by: Roverbeam
Date: September 11, 2024 03:24PM

1 1/4" BSPP
I bought a plastic (dummy) one from McMaster to test fit - it worked.

This site gives the thread specs, approximating Jim's metric measurements:
[amesweb.info]

Parameter Value
Pipe Thread Size 1 1/4
Threads per inch 11
Pitch of Thread 2.309mm
Basic Height of Thread 1.479mm
Height of Sharp V Thread 2.218mm
Major Diameter of Thread 41.910mm
Pitch Diameter of Thread 40.431mm
Minor Diameter of Thread 38.952mm



Edited 1 time(s). Last edit at 09/11/2024 03:30PM by Roverbeam.


MGBV8
Carl Floyd
Kingsport, TN
(4559 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: Oil filler thread size
Posted by: MGBV8
Date: September 11, 2024 05:02PM

This thread gives the same answer as Chad, 1 1/4" x 11 BSP.

[www.pistonheads.com]


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6507 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Oil filler thread size
Posted by: BlownMGB-V8
Date: September 12, 2024 09:14AM

Figured it was something like that. Best price so far on a tap is about $47 which is actually quite fair really but a good bit to pay for a single use tool. Much cheaper and easier than making one though. Thanks all, and I will double check the thread pitch this morning. Should fit the 11 tpi gage perfectly I would expect. It should allow me some lattitude in configuring valve cover vents and such.

Jim


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