Oil Filter Thread Question

[Lewis's Friend]

Hi All, a quick question. Really just curiosity on my part.

I have just tried to change the oil filter on my Jaguar AJ30 engine. I bought a Mahle OC460 filter (the right on for the car) to replace the Mann W719/36 filter on there. The new filter binds up on the thread however.

I have looked up the specs, and as far as I can see they should be the same. Both have a 3/4-16UNF thread, though the Mahle then also has '-2B' at the end of it's thread spec. Should this make sufficient difference to cause the Mahle to not fit? I may have just been unlucky and have a bad filter of course, but I just wondered if anyone else had seen this, or it the '2B' was of more significance than I thought (a quick google suggests it may refer to how tight the threads are cut)?

[saladdays]

I'd measure the old and new filters with with a vernier caliper and also a thread gauge. Here's a thread gauge: https://www.amazon.co.uk/KS-Tools-301-0090-Thread-...

Are the threads clean?

Just buy another filter?!

[GreenV8S]

You've got to suspect the threads are simply a different thread. You can compare the threads pretty quickly. Shove a piece of cardboard down the thread so that the thread pitchg is marked on the card, and see if both filters are the same. You can also compare the ID of the thread on the two filters. If they're a different thread diameter or pitch it should be pretty obvious.

[Lewis's Friend]

Fear not, I have bought another filter and that fits fine!

I was more just curious as I've not seen this before and also, non-metric things are not really my forte... I may see if I can dig out a suitable thread gauge just for my interests sake (lockdown gives time for boring things it seems!).