Race Engine Forum UK

I'm having a problem with my fabricated fuel rail. When screwing the pressure regulator into the end of the fuel rail, even with copper washers it's so far impossible to make a good seal, in fact it pours out. I have been able to screw a push on fitting into the same pressure regulator, and after some serious torque I managed to get it to seal.

Are there any sealants that will help make a better seal ? I understand I'll use some threadlock on screw-on fuel seals to ensure they don't work loose, but is there anything else that will have make a better seal without so much torque there's risk of stripping the threads ?

Here's a picture of the regulator, as you can see the regulator has all female fixings, and you can screw male push on ends or male screw on male ends
thank you
Sean

I have some Hylomar Universal Blue sealant , so it could try that

Ok so I had to go back to your 'readers car' post to see how you're doing this. In the back edge of the hex flats of the regulator should be O rings. If the regulator housing doesn't have a continuous 37 degree AN seat for the male fitting to sit against it must have orings on it otherwise it will always leak through the threads - the seat is what seals JIC AN fittings. Fuel lab regulators come with the orings for this reason. I had to blank off a fitting but the aeroquip -6 blanking plug did not have enough shoulder or head size to seal the o ring so I had to tap a washer to seal it which worked. If you do have a continuous seat in the housing then addition of a conical washer may help I believe EARLS sell them.

Rich

Teflon tape maybe?

yes someone else has recommended PTFE tape.

I wouldnt use PTFE tape on these type of fittings, at work we never use tape on small bore pipe work.

Try using a paste, like they use with nitrous systems.

Fittings as shown in your photo seal should 100% on the cones, male and female. They never leak - if the cones and threads are properly formed and matching. This is what makes Aeroquip and Goodridge fitings such popular choices.

Attempts to seal fuel lines any other way are very risky. I mean, don't do it. Why? Because they can spring a leak and cause a fire. Leaking fuel injection systems are incredibly dangerous because of the delivery pressure.

GC

Brooky wrote:I wouldnt use PTFE tape on these type of fittings, at work we never use tape on small bore pipe work.

Try using a paste, like they use with nitrous systems.

Interesting...what kind of paste is it, what base?
I taught teflon tape would do the job, its frequently used on water lines in houses which are under pretty high pressure but I was wrong as I see :)

Agreed that they should seal on the mating surface. That said tho, they're only as good as the machining job. I have in the past had bad fittings that wouldn't seal. I changed them out to replacements (of the same sort) and it fixed my problem. Check the mating surfaces are free from scores and other marks, debrie etc.

Worth noting that you must not connect alloy fuel unions to steel ones. This may be your problem. If you have to join, use braided hose with different fittings each end.

GC

http://www.holley.com/169101ERL.asp assuming

Its is documented by many autohrs including Guy, do not use any sealing tape or paste on AN fuel system fittings.