Hey everyone this will be my first time installing gauges. I have a 02 f-250. I will be installing glowshifts EGT, trans temp, and boost. I did my research and get the idea of how everything is done just have a few questions. For the EGT i found a 1/8th NPT-27 tap but it doesnt say to use letter R drill Bit it say use Q. Could i just use a 21/64 drill bit and still tap with 1/8 NPT-27 tap? Or is it the wrong tap. Also Could i use a little bit of threadlocker on the threads for the EGT and trans units? Thanks guys and if you have any other tips i should know of i would appreciate it. I should also note i will be drilling and tapping for the EGT on the driverside manifold. Is there a preferance of to where to drill and tap on the manifold.

 

Sorry I just saw this..
Gauge Installations at DieselManor- 1999-2003 7.3L Powerstroke

and here

http://www.engineershandbook.com/Tables/npttap.htm

21/64 = .328125, would most likely be deeper then you would want, but I dont feel it would be an issue.. thats my .02


Have fun with the install..but warning.. it leads to other things..

 

The tap I have is from Napa its 1/8th-27 npt pipe tap.and it says 5/16 for drill bit. I'm assuming the tap will still work once I get the hole drilled with a letter r drill bit instead of 5/16 drill bit correct

 

I thought the 1/8npt tap was real close to a 7/16 drill bit.

 

7/16 is .437. That is way to big. Used for 1/4" NPT.

Standard drill size is "Q" .332 drill. NPT Tap Drill Sizes - Engineer's Handbook

5/16(.312) will work if you can get it started. Depends on the type of NPT tap your using. Risky, but doable. I have done it.
21/64 (.328) .004 smaller than the Q. Will work super. I would have no problem using it and probably what i used to do mine. Hand drill with this drill will probably get you to .332. From wobbling while drilling.
.339 is "R". Will work also but wouldn't go any bigger.

Predrill your spot using a 1/4" drill bit. Finish it off with the 21/64" and you will be @ golden size for the tap. Start the 1/8" tap and go a 1/4 of the way of the treads. Turn the tap 1/2 a turn clockwise- 1/4 turn backwards. Fiddle it in slowly. try/check it often(depth). If not enough go to half way of the threads. Try/check.. etc.

Use a good tap handle and be as straight as possible to the hole you drilled. Shouldn't be a problem.

Here is a drill_tap chart. Doesn't have NPT taps. But shows decimal and Fractional comparisons for drills. Pretty handy chart to have laying around

 

the boost gauge tube is short. unless you got extra you are gonna have to put it on the bottom. i learned that the hard way after it was mounted up top

 

excellent post danskools and thanks for the help guys i feel more confident about it now. Im tapping the whole hole that i drilled out correct? Also did anybody use threadlocker on the threads or just snug it up.

When i was getting my gauges and wires together in the pod the boost gauge wires were the shortest so i put in on the bottom. Good thing i did otherwise it would have sucked thanks for the tip bcaughhorn.

 

No thread locker on mine, I just put it in snug. I have done three of them plus mine and none are leaking.

Yup, Tap the whole hole.
1/4" first (pilot hole)
21/64" (finish hole size)
Tap it. (checking often to check for size, Usually about half way down the tap threads will do)
Clean up by using shop vac over the new tapped hole.
I didn't use any lubricant on the drill or tap except maybe a shot of liquid wrench or wd40

3-Gauge Install Pictures

 

I learned that way too lol.
As far as prefrence as where to put the hole... where ever you can get in at and drill

 

well, i got the gauges installed and everything back together. Overall it was not as bad as i expected. A couple beers and being patient it worked out well. Whats everyone getting for readings? After about 30 min of driving on the higways at 60 i didnt pass 120 degress on the trans temp. egt's were at about 450-600 while keeping it between 55-60. For boost i saw 15 tops but mostly 10. I wasnt hammering on the pedal either just regular driving.Do Those seem like normal numbers.

 

Good job getting it done.

I only see about 3 or 4 on the boost gauge while cruising. You see 10?

Average take off i see around 8 to 10 psi.
15 boost is my max for me too.
Trans temp looks good.
EGT temp sounds about dead on to what i get.
Glowshift color on "green".

 

sorry should have worded it better. But after a couple drives i see 1-2 while crusing, and 5-10 on acceleration. Max was 15 when i was gunning it.

 

Sounds like your where you should be as far as temps. and boost. Your temps. will vary with outside air temp. all winter my trans temp didnt move, yesterday it was almost 80* and my trans temp read almost 140* A rule of thumb is to try not to let your trans. temp excede 100* ambient air temp. 15-17 psi boost is normal for stock tuning. Your egts are inline with mine

 

i forgot to mention i have my superchips set on mileage tune. I looked closer at the gauge while driving and sometimes it seems like 0 sometime 1 while just crusing at 55. Is that still normal or low boost? i still have plenty of power and havent noticed any power loss.

 

Cruising at highway speeds will show hardly any boost (0-2 lbs. at most). If you put your foot in it, you should see it build boost.