Im not sure if this is the correct forum, but i have isntalled my boost and fuel pressure gauges. I am getting ready to install the probe for my egt gauge, but the instructions say i have to use an R size bit which is .339 of an inch. I cant find an R size anywhere without buying a whole set of bits. Can I use a 21/64" bit. it measures .328"? If not what did all of you use.

BTW I just got my AD150 installed!!!! I love it 17 psi @ idle and 15@ WOT!!

 

yes that bit will work fine, when doing the actual tapping I like to go about a half turn at a time in then out it helps keep the thread filings cleaned out.........................make sure to put anti-seize in the threads before ya screw in the probe though

 

helps to put a little grease on the tap too, catches most of the metal pieces coming off

 

Another tip is to make sure you dont run the tap in too far (3/4 of the tap max) - if you do your thermocouple fitting will be loose.

 

thanks for the help guys. i hope to get this installed this week.

 

works well to let the truck idle while installing also to keep shavings out.

 

x2, been there done that

 

Me too. Luckily, a machinist buddy helped me fix that.

 

2/3 of the tap is more accepted. i could look it up so see what diameter the hole should be when finished. but as long as the fitting doesn't bottom out, you're good.

 

The point was that its easy to get carried away and go to deep.