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
No, but I can bring an oil filler plug to Townsend if it will help.
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:
https://amesweb.info/Screws/bspp-thread-chart-calculator.aspx#google_vignette
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
This thread gives the same answer as Chad, 1 1/4" x 11 BSP.
https://www.pistonheads.com/gassing/topic.asp?h=20&f=12&t=1425478&i=20
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