[TR] TR4 Fuel Delivery Issue & Mod

[Joel E. Justin]

This piqued my interest as I've had (along with others in my club) leaks at the fuel pump inlet, and it seemed logical if modern ferrules were 0.25" vs the original 0.30". I looked at several ferrules I have and they are all 0.25". So then I looked up the ferrule in the Standard Triumph Hardware Catalog. It is a TL0008 and according to the specs, it was: suited for pipe diameter 5/16" with a nominal internal diameter of 0.315"-0.318" and a thickness (length) of 0.250". So it appears that the length was not 0.300". Maybe the shape was different of the wall thickness was wider on the original ferrules???

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________________________________
From: keithstewart at bell.net <keithstewart at bell.net>
Sent: Tuesday, August 11, 2020 11:40 AM
To: 'EDWARD WOODS' <fogbro1 at comcast.net>; 'Greg Lemon' <grglmn at gmail.com>; 'staffel' <staffel at comcast.net>
Cc: 'Triumphs' <triumphs at autox.team.net>
Subject: Re: [TR] TR4 Fuel Delivery Issue & Mod


Ed is correct, it is the ferrule that does the sealing when it is compressed by the threaded fitting tightening down to the fuel pump housing. The fuel pipe threads into the fuel pump with a 5/16” compression fitting. If replaced, these may be prone to leaking fuel because the original ferrule was .297” to .303” in length whereas most North American ferrules are only .247” to .253” in length. Consequently, the compression fitting often bottoms out before the ferrule is properly compressed. The Roadster Factory sells compression fittings and ferrules that they claim do not have this problem. Also, several years ago, Scott uhring suggested using two ferrules end to end and filed down on the mating surface to get the necessary length.

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From: EDWARD WOODS <fogbro1 at comcast.net>
Sent: August 11, 2020 7:02 AM
To: Greg Lemon <grglmn at gmail.com>; staffel <staffel at comcast.net>
Cc: Triumphs <triumphs at autox.team.net>
Subject: Re: [TR] TR4 Fuel Delivery Issue & Mod



And isn't it the brass "acorn" that seals the connection at the pump, not the threads? ISTR that the original "acorn" is a bit longer than the replacements available which limits compression and can cause a leak. At one time there was someone making a longer "acorn" to solve this problem.



Ed Woods


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