Welcome to the North American Subaru Impreza Owners Club Friday August 22, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Factory 2.0L Turbo Powertrain

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 08-15-2002, 04:15 PM   #1
tnmn28
Scooby Newbie
 
Member#: 16071
Join Date: Mar 2002
Location: Daly City/Los Altos, CA
Vehicle:
2005 G35 Sedan
Twilight Blue

Default Is 1/8PT same as 1/8 27NPT ?

Hope this is the correct forum. I also tried a search.

I have the Defi BF EGT gauge. The instructions lists the bung as 1/8PT. I found a document on the web about using a 1/8pt-27npt metric tap. Is this correct? What size drill do I need? Where can I buy this, either online or local to SF Bay Area.

Thanks,
Anthony
* Registered users of the site do not see these ads.
tnmn28 is offline   Reply With Quote
Old 08-15-2002, 04:27 PM   #2
cnk
Scooby Guru
 
Member#: 10757
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NJ
Vehicle:
2013 BRZ Limited 6MT
DGM

Default

1/8"PT should be the same as NPT. Just make sure it's not BSPT. You can get a 1/8"PT-27 turn tap from Sears or Home Depot. The packaging should tell you what size you need for the tap as well. Sorry. . I don't remember.

Calvin
cnk is offline   Reply With Quote
Old 08-15-2002, 04:38 PM   #3
tnmn28
Scooby Newbie
 
Member#: 16071
Join Date: Mar 2002
Location: Daly City/Los Altos, CA
Vehicle:
2005 G35 Sedan
Twilight Blue

Default

Okay I'll try Sears.

On the Defi website they list the fitting as a 1/8PT part, but also two optional parts: 1/8NPT fitting and a 1/8NPT to PT socket.

So I'm confused?
tnmn28 is offline   Reply With Quote
Old 08-15-2002, 04:42 PM   #4
cnk
Scooby Guru
 
Member#: 10757
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NJ
Vehicle:
2013 BRZ Limited 6MT
DGM

Default

Hmm. . not sure about that then. I haven't looked at a Defi install. I got a Greddy EGT and that was a 1/8"-28turn BSPT tap that was required. Maybe someone else will be able to give you better directions than me. Best of luck!!

Calvin
cnk is offline   Reply With Quote
Old 08-15-2002, 05:15 PM   #5
n2xlr8n
Scooby Specialist
 
Member#: 18960
Join Date: May 2002
Chapter/Region: South East
Location: Bama
Vehicle:
02 WRX MBP
It lives! ; )

Default 1/8 NPT (-27)

The desig. 1/8 npt is 27 threads per inch; it requires a drill size of 5/16ths. Good luck!

Steve
n2xlr8n is offline   Reply With Quote
Old 08-15-2002, 05:24 PM   #6
WhatleyWRX
Scooby Specialist
 
Member#: 6634
Join Date: May 2001
Location: Boise, ID
Vehicle:
2002 WRX Sedan, Dirt
with some Silver patches

Default

Either way, you can use an "R" size drill. 1/8 NPT is 27tpi and 1/8 BSPT is 28tpi, the taper is slightly different from what I understand. From what I read my Greddy probe was 1/8 BSPT but after comparing it to my 1/8 BSPT and 1/8 NPT tap and die, I swear my fitting was 1/8 NPT.

The two are close enough to use either. If you install the thing into the manifold it doesn't matter. Its a pipe thread, so it won't leak if you are off by 1tpi. Just don't tap the thing too far, or you'll be hating life.

Anyway

Whatley

edit: Yes "R" is a drill size, although i see one of my drill charts says "R" the other says 11/32" take your pick. It's only .004 difference in drill size.

Last edited by WhatleyWRX; 08-15-2002 at 05:32 PM.
WhatleyWRX is offline   Reply With Quote
Old 08-15-2002, 05:40 PM   #7
tnmn28
Scooby Newbie
 
Member#: 16071
Join Date: Mar 2002
Location: Daly City/Los Altos, CA
Vehicle:
2005 G35 Sedan
Twilight Blue

Default

Cool!

Did I need to put any kind of sealant around the
fitting? I would assume it would need to be some
really high temp stuff.

Thanks for your replies.

Anthony
tnmn28 is offline   Reply With Quote
Old 08-15-2002, 05:49 PM   #8
WhatleyWRX
Scooby Specialist
 
Member#: 6634
Join Date: May 2001
Location: Boise, ID
Vehicle:
2002 WRX Sedan, Dirt
with some Silver patches

Default

No, it will be fine without sealant. If you really want to make in bombproof have the thing welded in place so it doesn't back out. Of course you probably have a stainless fitting, screwed into a cast piece so you can't just toss any old weld on there.....mine doesn't leak, I wouldn't worry about welding it.

Whatley
WhatleyWRX is offline   Reply With Quote
Old 08-15-2002, 07:51 PM   #9
stevedood
Scooby Newbie
 
Member#: 13841
Join Date: Jan 2002
Location: San Francisco
Vehicle:
02 WRX WAG

Arrow NPT Threads

Just for reference:

Pipe Threads
Size NPT Pitch (tpi) BSP Pitch (tpi)
1/8" 27 28
1/4" 18 19
3/8" 18 19
1/2" 14 14
3/4" 14 14


You can purchase the pipe thread tap either through McMaster, MSC Ind Supply, Grainger or at a local HW store. I would recommend putting some teflon compound/tap on the threads or heavy duty silicon grease at the very least. This isn't for sealing purposes but mainly to prevent galvanic corrosion or seizing. If you ever have to remove it in the future, you'll be glad you did. Average Teflon (PTFE) sealing tape is good to 400-500F with no problems.
stevedood is offline   Reply With Quote
Old 08-15-2002, 11:20 PM   #10
tnmn28
Scooby Newbie
 
Member#: 16071
Join Date: Mar 2002
Location: Daly City/Los Altos, CA
Vehicle:
2005 G35 Sedan
Twilight Blue

Default

Thanks for the reference stevedood.
tnmn28 is offline   Reply With Quote
Old 08-16-2002, 01:09 PM   #11
WhatleyWRX
Scooby Specialist
 
Member#: 6634
Join Date: May 2001
Location: Boise, ID
Vehicle:
2002 WRX Sedan, Dirt
with some Silver patches

Default

Good reference, the PTFE will drip off in under a minute. 400-500F is pretty low for EGT. "stevedood" mentioned some sort of grease, might see if they have some of that in high temp. I totally agree with him about using this if you are ever going to want to take it out. The corrosion will make life really suck when trying to remove it. Not sure why you would ever need to, but, you never know.

Whatley
WhatleyWRX is offline   Reply With Quote
Old 08-16-2002, 06:03 PM   #12
stevedood
Scooby Newbie
 
Member#: 13841
Join Date: Jan 2002
Location: San Francisco
Vehicle:
02 WRX WAG

Default try this...

I've used this compound for lots of stuff and it is pretty nice...
Dow Corning 111 Valve Lube & Sealant...service temp to around 200C (c. 400F)...silicone based, heavy consistency, resistant to most chemicals. Used for general high-temp sealing applications, ignition / boot contacts as well. Check through Grainger and you can find a tube for like $8 or maybe at a Grainger store in your area. I also use this stuff on my sway bar bushings.
There is also Dow Corning 41, extreme-duty bearing grease, good to 550F, and Dow Corning 7, a release compound similar to Dow 111 (same material). I wouldn't worry about the service temp because your pipe will be really hot regardless (1000 to 2000F) and synthetic silicone compounds like 111 won't be fully compromised at that temp...it will flow, though, and hopefully it will impregnate the metal surfaces, though, and keep the threads from fusing together.
Another option is to check out Loctite's brand of anti-seizing (Loctite White High Temp as en example) compounds which can handle higher service temps (2000F). Check it out.
Hope this helps.
stevedood is offline   Reply With Quote
Old 08-16-2002, 06:44 PM   #13
Corn-Picker
Scooby Specialist
 
Member#: 8679
Join Date: Jul 2001
Location: Morgantown, WV
Vehicle:
2010 The most hated
vehicle on the internets

Default

When I drilled and tapped for my EGT gauge I did so on the "casting button" of the manifold. If you look about 6 inches downtstream from the exhasut inlet you will see a button leftover from casting where the exhaust joins together in a Y confluence. I put my EGT gauge probe there because of the extra material afforded by the casting button, just something to keep in mind...

Also, tapping the casting button (at least on the driver's side) puts the probe in a good place when it's time to hook up the probe and start running wire. Wherever you choose to put your probe, make sure your EGT probe will be in an acceptable place once you reattatch your exhaust manifold. Of course that only applies if you are removing your exhaust manifold to drill and tap it, I am too uncoordinated to attempt something like drilling and tapiping with the manifold still on the car

Plus if you drill and tap the manifold while it is on the car you may have metal shavings in the exhaust, I would not want those upstream of my turbo.

One other tip, I don't recommend oiling the hole until after you are all done. All oiling a cast iron hole will do when you are drilling/tapping is make the little metal filings stick in the threads you tap.
Corn-Picker is offline   Reply With Quote
Old 08-16-2002, 06:57 PM   #14
tnmn28
Scooby Newbie
 
Member#: 16071
Join Date: Mar 2002
Location: Daly City/Los Altos, CA
Vehicle:
2005 G35 Sedan
Twilight Blue

Default

Thanks for your tips Corn-Picker! That is what I plan to do.
tnmn28 is offline   Reply With Quote
Old 08-20-2002, 09:15 AM   #15
cwb124
Scooby Specialist
 
Member#: 15571
Join Date: Feb 2002
Location: Not where you think
Vehicle:
2006 06 Forester XT
Silver

Default

Actually if you tap the hole while the engine is idling it will push almost all of the shavings out of the hole you just created. Any additional shavings will blow out through the turbo, which at idle is not spinning so there's nothing to worry about. A little trick a DSM guy told me about. Makes a lot of sense.

CB
cwb124 is online now   Reply With Quote
Old 08-20-2002, 03:04 PM   #16
stevedood
Scooby Newbie
 
Member#: 13841
Join Date: Jan 2002
Location: San Francisco
Vehicle:
02 WRX WAG

Default freestyle tapping?

Quote:
Originally posted by cwb124
tap the hole while the engine is idling ....CB
I think this is serious freestyle machining going on here...
If you drill the proper diameter clearance hole, tapping should be no problem. Using tap cutting oil is important, however, particularly on smaller diameter holes where the risk of breaking a tap is high. It's also important on harder materials like steel & titanium but with a brand new tap, it will be easier. You will feel more confident with tap oil (I promise) and it is used for a reason.
A few other pointers...
The first thread & a half is crucial...makes sure your tap is lined up with the hole by looking at it from two directions. A pipe thread tap is a tapered thread so it is also important to consider how deep you need to (can) tap the thread. Things to consider are the length of your EGT bung threads and the wall thickness of the manifold mounting point. Under-tapping the hole means the EGT bung, when torqued in, will sit higher. Regardless, pipe threads are generally not supposed to mate fully, usually proper thread engagement for 1/8"NPT fittings is about 50% thread length (0.405" long @ 27tpi = 11 threads = 5 or 6 turns to seat). An extra turn for good measure is OK, but anymore and you might compromise your thread & sealing at high temp. I'm not sure what material your bung is but hopefully it's steel (stainless or other) and not brass.
It also depends on how deep you can tap your hole, mainly, and a thicker mounting region (casting button) will let you get 11+ threads cut into it and good engagement. A shallow mounting point (<0.200") and I would maybe only tap it halfway.
As you start feeling resistance while tapping, back off a half-turn to clear the tap & let some of the filings out. I like to have a shop vac handy to pull the filings out as I go along. Don't back out the tap all the way until you are done because you can cross thread it easily re-tapping if not careful.

Afterall, you don't want to have to worry about this thing, right?
hope some of this is helpful.
~Steve
stevedood is offline   Reply With Quote
Old 08-20-2002, 03:09 PM   #17
tnmn28
Scooby Newbie
 
Member#: 16071
Join Date: Mar 2002
Location: Daly City/Los Altos, CA
Vehicle:
2005 G35 Sedan
Twilight Blue

Default

Steve,

Thanks again for more tips. Since you are in San Francisco and I'm in Daly City would you care to give me some help some time in the near future?

Thanks,
Anthony
tnmn28 is offline   Reply With Quote
Old 08-20-2002, 05:27 PM   #18
stevedood
Scooby Newbie
 
Member#: 13841
Join Date: Jan 2002
Location: San Francisco
Vehicle:
02 WRX WAG

Default

Anthony,

Let me get back to you, I saw your other post on BAIC and have been pretty busy with work...weekday evenings starting next week work best for me. What kind of timeframe/ how soon are you looking to get the EGT system up? I'd definitely like to give you some help, partially cause I'll need help doing some mods to my soob in the near future and also because I could always use some "therapy" time cranking bolts and fixing stuff. Just curiously, are you running a Vishnu system?

I have some of the tools for this and we can perform the work at your place (I live on a hill). Send me an email and we can coordinate.

Steve
stevedood is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Is '03 5MT same as '02? jasewyndu Transmission (AT/MT) & Driveline 1 02-22-2003 08:22 AM
is the WRX spring same as GC-8?? PrinceWRX Brakes, Steering & Suspension 1 10-21-2001 01:04 PM
GDA clutch same as GC-8 clutch? Tuning Factory Inc. Transmission (AT/MT) & Driveline 28 10-05-2001 10:02 AM
Is WRX midpipe same as the RS? Dan_E Factory 2.0L Turbo Powertrain 2 09-25-2001 01:31 PM
Heres a stupid question: Is 4x4 the same as AWD Andrew Newbies & FAQs 15 02-04-2001 03:53 PM


All times are GMT -4. The time now is 11:09 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.