farmer dave

What size of tubing is used for the fuel pressure gagues? I have an isolator with 5/32" tubing and I am going to take out the isolator. I want to put different compression fittings on it but can't find any. I was wondering if I could use 1/4" tubing instead?

HOHN

1/4" would be fine. I'd suggest you consider a hose instead of tubing, because nylon tubing (like you see on a boost gauge) can get brittle when cold, and will break when bent back and forth.

I'd recommend instead that you go with either grease gun hose (connected by other hose), or a different tubing material. Copper or poly should work. My guage is plumbed with GG hose to braided back to GG hose at the guage. There's a needle valve in there, too.

hth

farmer dave

The small kits that you get for oil pressure gauges are nylon tubing? I always thought that they were just a plastic tubing.

If I do use a copper tubing will it rattle from the pulsation? I will have a needle valve in it also.

I think that it would be kind of hard to run GG hose to a pilar. Are your gauges on the dash instead or are they in a pilar?

infidel

I've had the same 1/8" nylon boost tubing to the fp gauges on both my trucks going on eight years now, but it only gets down to minus 40 here. I do push it though some 1/4" tubing to form a protective sheath against kinks, cuts and abrasion though.

There is no fuel flow through the tubing to the gauge, just pressure change, no reason at all for large tubing.
I would stay away from copper tubing, it will eventually break from engine movement.

farmer dave

So I can use the tubing for the oil pressure gauges. It rarely gets that cold here.

I don't have to purge the line of air?

infidel

The air makes very little difference and will eventually be replaced with fuel, don't worry about it.
I don't like the tubing that comes with the oil gauge kits, it comes in a fist sized ball and wants to keep on rolling back up. Pushing it though 1/4" tubing will cure this, but even that's hard to do.
What I prefer to use is 1/8" air brake line sold by the foot at most auto parts, much easier to work with.

Vulcan

I use 1/4 in fuel line, 1/8npt X 1/4 brass barbs and some small restrictors I made and thats it and works great. No need to spend a lot of money