I know the size of the tap is 3/8-18 and im pretty sure the drillbit size is 37/64. But what i want to make sure of is that im using the same size tap/drill bit that everyone else did. Let me know what size tap/bit you used for the hole and maybe provide a picture or something for my viewing pleasure. Ive searched, done it all, just double checking now

 

Actually, I believe the thread for the sender should be NPT or BSPT pipe thread. Check the manual on Defi's site (http://www.defi-shop.com) if you don't have yours - I know it's listed in the manual. You definitely don't want a straight thread - you need the tapered pipe thread to do the job right.

BTW, NPT = National Pipe Thread, the US standard. BSPT = British Standard Pipe Thread, which is the metric version. Most all Japanese senders are 1/8" size - funny thing is it's 1/8" BSPT - you'd figure it would be a metric size, not 1/8 inch .

Can't remember what drill bit goes with the pipe thread taps - I always Google it when I forget .

Dale

 

https://www.rx7club.com/showthread.p...hlight=install

Looks like 1/8-27 and 11/32" bit size is what you need. And this thread has pictures.

 

Ive already read through that thread, the problem is that the temp sender on the DEFI gauge is not 1/8, its 3/8, so that FAQ is all wrong as far as specs go. a 3/8-18 NPT cap fits on the tap and on the sender perfectly, so im pretty sure this is the right size. Maybe this is an older revision? Should my sensor be 1/8 instead of 3/8? I bought the gauge used from Fritz so it didnt come with a manual. Thanks for the help guys, hopefully somebody who already had this fiasco will chime in and fix all my problems

 

I just installed a Defi D Gauge yesterday for water temp, it was definately 1/8-27, although the other lines of Defi gauges may be different.