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Post by Deleted on Jan 11, 2018 12:10:49 GMT
Hi All
Whilst doing some research on fuel line fittings I came across brass compression fittings, basically the sort a plumber uses but for fuel systems. Has anyone used these before? would like to know if there are any pitfalls as they look like the solution to my problem. The will connect to copper or rubber pipes and can take the pressure of an efi system.
Any info greatly appreciated.
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Post by Deleted on Jan 11, 2018 12:12:43 GMT
Like this or compression fitting at both ends, can be different size at either end.
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Post by ancsportscars on Jan 11, 2018 13:51:39 GMT
Not used them myself but probably worth asking over on the locostbuilders forum for, if they are suitable, someone's bound to have used them. How far away is your nearest IVA centre - may well worth popping in and asking them? I would guess that provided you can present proof that they can take the pressures required, then, apart from being a little bulky, they'd be fine. What's your present connection method and what is the issue with it?
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Post by R2S on Jan 11, 2018 13:57:43 GMT
Forgive me if its a stupid question but why not flare the end of your copper lines?
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Post by tojeiro on Jan 11, 2018 14:25:50 GMT
Assume that you are only considering specific automotive fitting for fuel. I understand that plumbers brass fittings only work when applying to a soft pipe material (i.e. copper as the olive can actually crush the pipe slightly). Cupro nickel may still be OK but these olive type fittings generally don’t like vibration or any movement. I work in industrial pumps for the oil industry and we are only allowed to use compression fitting on non-hazardous/flammale fluids, even then we only use ‘Swagelok’ stainless steel compression fittings which are a more sophisticated design. No clear what is causing your leak, could you not just use double hose clips. I thought about swaging the pipe ends but kept being left with sharp edge, so I basically just soldered on standard olives to create a smooth bulge to prevent the hose blowing off. You probably don’t want to do that however if you have alrrady had fuel in the pipe! by -Tojeiro 74-
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Post by Deleted on Jan 11, 2018 14:39:10 GMT
Forgive me if its a stupid question but why not flare the end of your copper lines? They are flared but it has leaked a little. Currently the connection is dry but bit risky to not address. I started it on a really cold day and under pressure it was dripping.
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Post by mscott on Jan 11, 2018 14:43:59 GMT
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Post by Deleted on Jan 11, 2018 14:46:59 GMT
Hi tojeiro
Already using double clips although thinking of changing to the crimp type as one option. Using an olive to help with the seal is a good idea but as you said a bit risky at this stage. I do have a hot air soldering iron but I would really have to change the whole line to be safe.
Not looked into the IVA manual but these things are sold as a fitting for fuel lines, they are not suitable for brakes but everything else appears ok. Going to have a read of the iva guide and see what it says.
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Post by Deleted on Jan 11, 2018 14:52:02 GMT
Hi mscott
You need to use those clips for the iva, using jubilee clips is a possible fail as they are meant for the cooling. On my iva for the Westfield I had used the crimp connectors on the fuel pump and the iva man was impressed with those, he said they don't usually see them on an amateur build but they liked them.
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Post by Deleted on Jan 11, 2018 15:00:00 GMT
I might go down the route of swapping the supply pipe and getting a good flare and using an olive. Now it is all in it is hard to work on. I have already decided to swap the rubber pipe just to be sure. Might build a fuel pressure gauge in to the line at the same time.
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Post by R2S on Jan 11, 2018 17:47:04 GMT
Main reason i went rubber full length was to avoid the problem you have encountered, is it too late to revert to rubber full length?
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Post by snowbird1 on Jan 12, 2018 14:36:14 GMT
In a perfect world the hose should seal on the flare - the main purpose of the clip is to prevent the hose sliding off the pipe. Are the hose and pipe sizes compatible, a 8 mm ID hose will be a bit loose on a 5/16" pipe. It should be quite hard to force the hose over the flare.
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Post by Deleted on Jan 14, 2018 10:13:46 GMT
Main reason i went rubber full length was to avoid the problem you have encountered, is it too late to revert to rubber full length? Definitely an option. Now the car is 99% done getting to the pipe ends to work on them is tricky so dropping the entire line to work on will not be much more work. If I drop the entire line I will probably replace it anyway, moving the join away from the hard to reach bulkhead area would be a good idea. Been looking at the stainless braided tubing. What did you use?
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Post by ancsportscars on Jan 14, 2018 10:42:35 GMT
Be careful with stainless braided rubber hose.
It's known that the ethanol in unleaded will react with rubber - causing it to perish prematurely. If its hidden underneath braid, you will not see the cracks developing - leading to possible leakage and fire risk.
I remember the rubber hoses on my first kit car I built were completely shot after less than two years - so its imperative they are inspected regularly!
When choosing rubber fuel hose, apart from suitability for fuel injection, ensure it is marked SAE J30R9 which supersedes SAE J30R6 and is reputedly more resistant to ethanol.
I've read that Super Unleaded doesn't contain ethanol - (though, apparently, it does in the South West) but don't know for sure how true that is. However, those that do use Super Unleaded reckon their hoses show no signs of perishing.
Food for thought.
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Post by R2S on Jan 14, 2018 11:27:42 GMT
Main reason i went rubber full length was to avoid the problem you have encountered, is it too late to revert to rubber full length? Definitely an option. Now the car is 99% done getting to the pipe ends to work on them is tricky so dropping the entire line to work on will not be much more work. If I drop the entire line I will probably replace it anyway, moving the join away from the hard to reach bulkhead area would be a good idea. Been looking at the stainless braided tubing. What did you use? I used this www.carbuildersolutions.com/de/gates-fuel-hose-8mm-516Wasnt aware of any problems with these rubber pipes (ANC comment above) but my pipes are visible and in the event of needing replacement positioned for easy pull through using old as 'draw string' for new. Bottom two rubber pipes are feed and return, upper rubber is the vent system, and hard line is brake pipe. I'm also aware that some form of documentation is required from the manufacturer re the pipe spec, I downloaded it but now cant locate it so will have to do this agin. Fitted without joints
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