[nytrainer]

Wanted to change my plastic mechanical oil pressure gauge tubing to something more reliable. What's best? Copper tubing with compression fittings, or is there something even better?
Thanks.

[chrisp]

Go with the copper , make a loop @ both ends like a slinky for movement .

[Radman]

Copper doesn't melt if it bumps the exhaust system. Plastic will be a big smoking messy problem in an instant. Your choice.

[Chris65LeMans]

I replaced my plastic one with copper. I saw a guy with a woven steel one at a show. That's what I may do if I do it again.

[Sirrotica]

I use 3/16" double flared steel brake lines. The double flare should seal up to 2000 PSI and steel won't work harden from vibration as copper does. Work hardening makes the material brittle and subject to cracking from constant vibration. The larger 3/16" ID also reacts very quickly when the pressure changes. It may be overkill, but all the vibration a dirt race car sees I've never had any issues.

A double flare fitting is superior to a compression fitting for sealing with out loosening. Compression fittings brass farrells pinch the softer copper tubing causing leaks occasionally also.

[jonmachota78]

Good question. I bought the copper line kit then thought naaa. So I bought the braided stainless kit. So now I've got both kits on the shelf and the nylon stuff is still in the car.. (No where near exhaust)

sirrotica you're saying you have steel brake line routed from your sender to your dash guage? Wow I'm trying to get my head around that. Steel line doesn't work harden?

[Squidward]

I have nylon now, will go copper soon, like this week.

I had the plastic tubing split behind the dash once in my 73 Formula. I saw it gurgling up at the speaker grill. What a mess!

[Sirrotica]

No steel line doesn't work harden, that's why it's used for brake lines. Copper used to be used as a replacement on brake lines years ago until it was found it work hardens and cracks.

I use a pre fab brake line with the ends already flared and fittings installed available in various lengths at all parts stores. It is malleable so it can be bent to fit whatever application it needs to be same as brake line can be bent to fit a chassis. I insulated it with slit vacuum line where it goes through the firewall. I've seen nylon melt, and copper leak at compression fittings because it is softer than the brass farrell.

It may be overkill, but I never worry about it leaking or burning through because of exhaust or a fire in the engine bay (it does happen occasionally in a race car)

[Schurkey]

Routed properly, there's nothing wrong with the nylon tubing supplied with the gauge. Well, I'm hoping that cheap-junk Chinese tubing is still satisfactory. My experience has been with the plastic tubing supplied with name-brand gauges from decades past.

The important part is "routed properly". Any plumbing--steel, copper, or nylon tubing, or "steel braided" hose--is going to need to be properly secured, allowances made for engine shake including chassis deflection under load, and prevented from chafing or abrading on absolutely anything like sharp sheetmetal, rough or sharp castings, etc.

I've used nylon tubing for years 'n' years with zero problems. I also had an oil leak onto the carpet of my Toronado because I got stupid with the routing, and the stuff got cut on a sheetmetal bracket that it vibrated against. Dumb, obvious, and easily preventable--if I had paid attention.

[pugslyx234]

I personally dont like any oil line inside my car, I leave it under the hood and monitor it at the times the hood is up which seems like always. One can listen and usually the lifters start clackin if oil pressure goes south. FWIW

[Old Goat Racer]

I use this

http://www.summitracing.com/search?S...yword=atm-3229

[lust4speed]

I have nylon tubing in the Cruiser and no problems. Only oil line failure I ever had was the stainless -4AN line in the drag car. Stainless hose has a rubber inner liner that definitely has a limited lifespan, and the stainless outer layer hides the condition of the rubber. Replacement was a stainless hose with a Teflon liner.

[JSPONT]

Originally Posted by pugslyx234

I personally dont like any oil line inside my car, I leave it under the hood and monitor it at the times the hood is up which seems like always. One can listen and usually the lifters start clackin if oil pressure goes south. FWIW

By the time you hear it its to late!

[Old Goat Racer]

Originally Posted by lust4speed

I have nylon tubing in the Cruiser and no problems. Only oil line failure I ever had was the stainless -4AN line in the drag car. Stainless hose has a rubber inner liner that definitely has a limited lifespan, and the stainless outer layer hides the condition of the rubber. Replacement was a stainless hose with a Teflon liner.

Curious, how old/young was that stainless/rubber line?

[Skip Fix]

I know some guys slide rubber vacuum hose over the copper for shock and wear resistance also.

[lust4speed]

It was over 16 years old, just one of those things I didn't think about going bad.

My drag car has the water temp and oil pressure gauges on the cowl outside the windshield, and it was a fine mist that let me know the stainless oil pressure hose had reached the end of its life. I suspect a hairline crack in the liner finally went deep enough, but at least it didn't rupture. I also had stainless feed and return fuel hose and after the oil line problem, replaced those with aluminum tubing feed line and nylon braided return line. It's been another eight years, and the -10AN nylon braided blue return hose is starting to show hairline cracks in the outer layer, but at least it is letting me know it is aging.

[BILTIT]

Stainless steel tubing and compression fittings is the way i went, have it at work though so its easy to get for me.

https://www.swagelok.com/

[Old Goat Racer]

Originally Posted by lust4speed

It was over 16 years old, just one of those things I didn't think about going bad.

My drag car has the water temp and oil pressure gauges on the cowl outside the windshield, and it was a fine mist that let me know the stainless oil pressure hose had reached the end of its life. I suspect a hairline crack in the liner finally went deep enough, but at least it didn't rupture. I also had stainless feed and return fuel hose and after the oil line problem, replaced those with aluminum tubing feed line and nylon braided return line. It's been another eight years, and the -10AN nylon braided blue return hose is starting to show hairline cracks in the outer layer, but at least it is letting me know it is aging.

Good info, thanks

[BruceWilkie]

I have had good luck with electric oil gauges on several vehicles. Both Autometer and Sun... Response is very good compared to an Autometer(Sport Comp) mechanical and a few off brand I tested quite awhile ago. An old 70's Sun mechanical was slowest...had a very small entry orifice.
Easy hook up and only possible leak is at the sender... like any wired accesory protect wires from getting damaged with proper routing, grommets, sleeves etc..

[b-man]

The 1/8" copper tubing is fine for what you're doing.

Had it on my daily driver 455 plumbed into an Autometer gauge for 5 years and 30K miles and never an issue.