I was one of the ones Baz mentioned, my oil guage sender snapped off right at the end of the track day.
Banzai is correct, the thread you have is probably 1/8 NPT which is 28 threads per inch. The SR sender hole is 1/8 BSP which is 27 threads per inch. Don't force it in there, it's not going to seal properly. You can get a 1/8 NPT to 1/8 BSP adapter made up from places like Pirtek, but a much better idea is to make a remote sender block and run some braided hose to it. I can take a pic of my setup for you this afternoon if you like.
Basically you make a braided hose with 1/8 BSP fittings (I used Speedflow). Then get a piece of square bar about 20x20mm and about 100mm long. You then drill a hole through it lengthways (you may need to accurately measure and drill from both ends if you dont have a long drill bit). The drill a couple of holes on the side of the bar which break into the main hole you drilled first. Tap the holes to 1/8 BSP or NPT respectively then you can screw in the braided hose, the gauge sender and the SR factory idiot ligt switch. Finally you put a grub screw in the open end of the long hole to block it off. Hopefully that made some sense to you.
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