I am following instructions on how to install a EGT senor on my manifold...I have drilled the hole and now I am ready to tap...I have a 1/8 BSPT tap and a 1/8 NPT tap...I want to use the BSPT tap because that will match my sensor threading propery with my DEFI unit...now this tap is only about 2+ inches in overall length and it has a 1/2" square end on it to affix a tap wrench...I can't find a tap wrench that will be long enough to clear the head of my engine so I have enough room to work...can you recommend a tap wrench that would fit my tap and allow me to clear the head and do the work without taking off my manifold??

Thanks in advance

Anthony Schwaiger

 

Just use a socket, extension and a wrench. Use oil to keep the tap lubed.
BSPT can be tapered or parallel. IIRC, the male probe threads are tapered.
If they are parallel, you should use a tapered tap.

BSPT and NPT are basically the same w/ BSPT having a 55* angle taper and NPT having a 60* taper.

 

Some ratchet extensions work...

most tap handles have a sliding "T" portion so that you can turn it 180 degrees and then slide the handle over to turn it for the next 180 degrees and so-on.

It sounds like you're tapping it fairly close to the engine so fighting with the tap handle's gonna cause you to get real warm real fast...I did findd a tap handle for mine that looked like it wouldnt fit so I pried open the jaws and used a vice to get the lock-nut back on.... i'll never get my tap back out of the handle but i was able to do the work with plenty of clearance and leverage.

 

Thanks I'll try them and see if they work...if anyone has any better ideas let me know

 

You can also purchase a tap socket set. The tap will slide in the end of the special socket and you can then use a 3/8 extension and ratchet to tap the hole. Also don't use oil on the tap, use bearing grease. The grease will catch and hold all of the metal shavings so that they will not drop in the manifold and lubricate the tap at the same time.
<---This is what you need.

 

ahh sweet...thanks man

 

use a socket/extension method. also be certain no to run the top down tooo far into the exh man, as the egt bung might not tirghten up.

if you look @ the tap, you'll see that the tap gets thicker the further you go up the length of the tap. get some threads started, remove the tap & see how the egt piece goes in.

just remeber to do the 180/360/180/360/180 deg method with teh tap. screw it in a bit, once you start cutting threads, turn the tap out 180 deg, then go in 360, back out 180, go in 360, back out 180, go in 360 until you reach your desired tap depth.

the reason why you back the tap out 180 deg, is to break up the pieces of material you just cut out. cause, if you just run the tap down, without going back & forth, you'll break the tap.

 

i agree with the above but i would pull the manifold arent you parinoid of get metal shavings in the turbo?

 

Yes...yes I am

but I just see how things go...not exactly safe..but oh well...if it breaks my turbo I guess I can always get a 20-G or an evo green...heh heh...yeah I just hope it won't

 

Actually the difference between BSPT and NPT is 1 extra thread per inch. Pipe thread is tapered by nature. Not tapered equals a normal tap. They are not basically the same. The will not interchange. You will ruing the threads on one of the two things.

You can use a 8 point socket on your tap. But make sure you keep it straight! It's extremely hard to keep a tap straight without the wrench. I ruined my probe fitting by tapping it crooked. I do have an extra probe fitting if you run into trouble. I beleive it's BSPT.

 

Thanks for the advice...I might need to take you up on that fitting...appreciate it