I have a Mallory fuel pressure regulator and am having a hard time sealing the 3/8 NPT fuel fittings and plugs. I tried Teflon tape and paste to no avail. What's the secret here?

Thanks,

Jarrett

 

If using teflon tape, you have to turn it around the fitting a good 10 times or so. It requires alot more than water hoses and stuff. Another product people use is that liquid teflon, brush it on and screw it in, then wipe off the excess.

 

No secret to it. I did mine with 4 or 5 wraps of teflon tape and it worked fine. Perhaps you were given/bought the wrong fitting?

 

Sometimes those NPT fittings are a little off. You try to tighten them and they feel tight, but still allow fuel to leak. Try another fitting. Make sure it can thread in a turn or two by hand, dry (no tape or goop), before you purchase it.

 

Fuel can get thru all kinds of tiny cracks that oil or water couldn't possibly pass. Best is to make sure all fits are very clean and accurately made. Rough threads will pass fuel. IMO the purpose of teflon tape is not to seal but to allow you to tighten joint more. YMMV. Sometimes you just gotta throw pipes and fittings away and start over because they can't be sealed as an afterthought.

 

I had a shop sell me some fittings that I could not seal for the life of me, it ended up that the rookie at the counter brought me ones that wernt NPT, some other sort of fitting that had no taper, once i got the right ones it was no prob tightened em up w/teflon tape 2years now and no leaks yet

 

I've found that dry fitting is essential. It lets you know how the threads feel before the final tightening. There was a problematic fitting on my bro's Holley pressure reg that leaked a bunch of gas on the first test drive. I kept it around and found a new use for it, on PercentSevenC's Holley pressure reg in a 90° 'street' fitting on the inlet. It appears the threads in the street fitting were cut slightly larger than they should've been, and that faulty fitting was just right where a normal fitting went all the way in and partially blocked fuel flow.

So even if the threads aren't 100% perfect, the fitting may still work in a different application. I'm glad I kept that fitting because if I didn't, it would have meant another trip to the store.

No leaks out of the faulty fitting, but ironically a known good fitting leaked a little bit. I wrenched it down and haven't checked it lately because I haven't smelled gas. Wait a minute, after the suspension lifters were installed I did smell gas, but maybe it was a little spilled gas at the back of the car.

 

Thanks guys, I'll try those tips.