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Series 2 gas tank vent fitting


Bill

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Does anyone know the thread spec for the Series 2 gas tank vent?  I checked with Ken at Dave Bean and his research indicated it was not BSP or Whitworth and I confirmed that it was not SAE or Metric. What else could it be? We are stumped!

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Comparing it to the 1/2-20 in the photo, it looks like it could be 1/2-28 which is a UNEF size.  Do you have a thread pitch tool for that thread size you could compare? Perhaps a 1/4-28?

 

-John

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As John said, it appears to be a finer thread pitch than the 1/2-20.  You should be able to calculate tpi with measurements - and if you can measure the angle of the thread event better as there are several resources for identifying fittings with this information.  www.britishfasteners.com is one I use.  British Standard Brass is 1/2-26, so that is a possibility if this is an original Serck fuel tank.

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Wow guys, I appreciate the shout out, but I actually have no idea what that thread would be! As many years as I’ve played with these cars and all the bits and details I’ve scrutinized, it always amazes me when someone asks about something so simple that I have simply never needed to consider. I have done some work in my own fuel lines and have had my tank in and out a few times, but never had to find a new fitting for the pick up.

 

Bill, what happened to the old fitting?

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Thank you, guys! We are getting closer to an answer! I don't have a tread pitch gage but here is a 1/4"-28 for comparison. the fitting could very well be a 1/2 x 26. 

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On 1/21/2022 at 5:49 PM, SENC said:

I now have a thread gage and the threads do measure 26 TPI.  The fitting matches the British Standard Brass (BSB) 1/2-26 size. Fitting of this size are apparently no longer available. Taps and dies are still available but under the circumstances I think that I will just use 7/16" ID gas hose with a hose clamp.   Incidentally www.britishfasteners.com is an excellent source of info. Thanks for all the help!

On 1/24/2022 at 4:09 PM, Bill said:

Thank you, guys! We are getting closer to an answer! I don't have a tread pitch gage but here is a 1/4"-28 for comparison. the fitting could very well be a 1/2 x 26. 

IMG_2696.JPG

On 1/24/2022 at 4:09 PM, Bill said:

Thank you, guys! We are getting closer to an answer! I don't have a tread pitch gage but here is a 1/4"-28 for comparison. the fitting could very well be a 1/2 x 26. 

IMG_2696.JPG

Thank you, guys! We are getting closer to an answer! I don't have a tread pitch gage but here is a 1/4"-28 for comparison. the fitting could very well be a 1/2 x 26. 

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Obviously, I am a novice when it comes to navigation this web site. The below statement is from me and not SENC. 

 

I now have a thread gage and the threads do measure 26 TPI.  The fitting matches the British Standard Brass (BSB) 1/2-26 size. Fitting of this size are apparently no longer available. Taps and dies are still available but under the circumstances I think that I will just use 7/16" ID gas hose with a hose clamp.   Incidentally www.britishfasteners.com is an excellent source of info. Thanks for all the help!

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@Bill I just added brief descriptions on how to quote single & multiple posts to the FAQ located here.  There is also other information in the Forum Help Guides section that may help you navigate the software.  Feel free to send me a PM if you need any assistance.  Now back to the thread topic :) 

 

-John

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