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Forum nameEngine Management Systems & Controllers
Topic subjectwhat are the tap specs for the GM sensors
Topic URLhttp://forums.2gnt.com/dcboard.php?az=show_topic&forum=54&topic_id=1466
1466, what are the tap specs for the GM sensors
Posted by CarbonFiberRST, Dec-31-69 06:00 PM
like the subject says... the dude at the machine shop says its 3/8 with 18 thread pitch but he can't find that anywhere... Is this the correct specs I would use to order a tap? I am clueless in this area, i don't even have a drill so yea. please help. (GM IAT and coolant temp sensors)
1467, RE: what are the tap specs for the GM sensors
Posted by dougie2, Dec-31-69 06:00 PM
You need to use a 3/8" NPT tap for both sensors.

NPT = National Pipe Thread
1468, RE: what are the tap specs for the GM sensors
Posted by Star Turbo Talon, Dec-31-69 06:00 PM
Ditto, very easy to find at any tool store. 9/16 drill hole.

Terry
1469, RE: what are the tap specs for the GM sensors
Posted by dougie2, Dec-31-69 06:00 PM
A 9/16" drill is often used and will work with a 3/8" NPT tap, but it'll be a little tight when you start the tap. The correct drill size for a 3/8" NPT tap is 37/64".

For anyone looking to buy a 3/8" NPT tap, you will not find it at any auto parts store. You also will not find it at Lowes, Home Depot, etc. You can get cheap carbon steel pipe taps at places like toolbarn.com though.
1470, RE: what are the tap specs for the GM sensors
Posted by CarbonFiberRST, Dec-31-69 06:00 PM
http://www.toolbarn.com/product/magna/95498/ they say to use a 9/16 too...

EDIT: I ordered that one... hope its right. thanks for the help guys.
1471, RE: what are the tap specs for the GM sensors
Posted by Star Turbo Talon, Dec-31-69 06:00 PM
Well Doug is right, if you use a 9/16 you have to tap from the biginning of the tap, if you use a 37/64 you start later in the tap and makes for a little less effort. Different tool amnufacturers prolly recommend a slightly dif size. Snap on i have says to use a 9/16 but it would be a tiny bit faster if you used a 37/64.

Either will work


Terry
1472, RE: what are the tap specs for the GM sensors
Posted by dougie2, Dec-31-69 06:00 PM
Yeah, either will work just fine. Most people use 9/16" because that's what they have and they don't have a 27/64" in their tool box.

The only bad thing about using a 9/16" is that it's a bit more difficult to tap straight in and not at an angle (especially with odd parts like water necks and manifolds.

TIPS: Take your time, use tap/die fluid, clean the tapped threads well, and take your time. ;)
1473, RE: what are the tap specs for the GM sensors
Posted by XtremeRS, Dec-31-69 06:00 PM
A "good" specialty hardware store should have the tap..thats where i got mine from..wasnt cheap either.. :) It usually will say what drill size right on the tap as well, just fyi..
1474, RE: what are the tap specs for the GM sensors
Posted by djtrickee, Dec-31-69 06:00 PM
Originally posted by XtremeRS
A "good" specialty hardware store should have the tap..thats where i got mine from..wasnt cheap either.. :) It usually will say what drill size right on the tap as well, just fyi..


I got mine at my local Ace hardware store. They kick home-depots ass. I love em.
1480, RE: what are the tap specs for the GM sensors
Posted by RxR_Eclipse, Dec-31-69 06:00 PM
Ace hardware here as well. Like 9$.
1481, RE: what are the tap specs for the GM sensors
Posted by dougie2, Dec-31-69 06:00 PM
Ace Hardwrae is the shit!
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