I bought an external oil filter head for the spin on type oil filter, part number 063139, from NOC shop recently but I can't identify the thread in the mounting holes. It is a fine thread but not cycle thread (26 TPI) or BSF and it is not metric. It might be UNF but I have no bolts or taps to check.
I should be grateful if anyone can tell me what the thread type and size is.
Dennis
Norton parts sourcing.
Wasn't the whole bolt-on filter head a French car part originally ? The risk of course is that one of the later suppliers will have assumed an Imperial thread and retro-manufactured...a bit like Wassells years ago when they put BSF threads in Commando camshafts.
Thread Sizes
Richard is correct in that the original oil filter design was pinched from something like a French Citreon 2CV. In which case metric threads for the filter body and mounting bolts would make sense...........However.........
5/16" is about 7.98 mm
8 x 1.25 roughly equals 5/16" x 18 tpi UNC which also roughly equals 5/16" x 18 tpi BSW.
I stand to be corrected on any of the above..
Command filter housing?
A real original norton commando filter housing and good after market ones made to original spec are 5/16 UNF.
Beware of aftermarket ones as the spin-on thread have on more than one occasion , NOT been square with the gasket surface.
Beware also the pushed in…
Beware also the pushed in pipe spigots that come out, go for the screwed in version if possible.
Beware the Black Paint
I worked on an elcheapo aftermarket one where the internal black paint had flaked off and very nearly blocked off the outlet!
Thanks everyone.
Thanks everyone for your replies. I am pretty sure the threads are M8 and were just poorly cut. I re-cut those and they are fine and secure.
Dennis
Looks like I have asked this question before? Must be old age. I searched the forum and the answer supplied was 8mm x 1.25 and that fits. I had to refresh the threads with a tap but it is fine now.
Dennis