Fuel Hose ref: Re-Cycle #116

Anything to do with nuts and bolts that is not associated with a build thread
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JamesF
Rickman Guru
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Joined: Sun Dec 08, 2013 9:37 am

Fuel Hose ref: Re-Cycle #116

Post by JamesF » Mon May 01, 2017 9:01 am

I read with interest the article referring to Scimitars and while fuel hose is an issue with modern fuel that is not the "whole story". I had an SE5a for 15 years and would like to expand on the issue. i did have an article printed in Slice which became a popular mod to avoid under bonnet fires. I would have liked to post it here but only moving recently can't find the "Slices" box.

The Scimitar and Ranger are fibreglass and this does result in higher under bonnet temperatures. The Scimitar is worse though as one has a V6, so any leaking fuel will sit on the manifold and drip onto the exhausts. The advantage of XFLOW is this doesn't happen.

The Weber carb 38DGAS, ICH, and others just had a fuel nozzle secured with an interferance fit. Unlike the Weber 32/35 (and earlier ones no doubt) which had a threaded nozzle. I suppose it was to save manufacturing costs! With the Scimitar the problem was a combination; of longer length of fuel pipe creating 'loading' on the nozzle and the higher temperature causing the aluminium (Mazak material) to expand more than the nozzle. So they could work loose and a fire result. Reliant recalled new cars and pinned the nozzle which helped avoid the loading... but some still leaked.

Simple solution is to remove the nozzle, find a threaded nozzle and tap a new hole. I couldn't find a suitable nozzle as the surrounding material was also reduced leaving a thin wall.

But I did find a solution. The nozzle for me just pulled out with fingers. The diameter was perfect for a 3/8 UNC tap which allowed me to screw in a blank. I removed the brass filter and found the thread was the same as a truck air blank plug (19mm). Meanwhile the only nozzle I could find was a 1/8 NPT facet fuel pump - 8 mm nozzle. So drilled the plug to 1/8 NPT, inserted nozzle and joined to the carb. Now the supply was vertical with no loading and safe. The filter I replaced with an inline one and fine. The fuel hose I bought was from Ford and was I recall £10 per metre which was about 1994 so was expensive. That mod worked fine for almost 14 years until I sold her.

I haven't researched fuel hose recently so can't comment on the one mentioned but would say don't buy cheap hose.

Of course the other solution is just to buy a new carb top but not cheap and one is left with the same potential problem of fire.

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