oil pressure gauge lines: steel vs copper

[The_architect]

One of the first things I did when working on my recently acquired Bugeye was break the steel oil pressure gauge line right at the fitting which goes into the engine. In order to stay on the road I plugged the line with solder and have gone without an oil pressure gauge for awhile.

I got a new line and fittings from a source in the UK, but the line is copper. I've read elsewhere about copper lines becoming "work-hardened" and brittle, at which point they break off and before you know it all your oil is gone!

So I'm wondering if I should go back with steel instead. Originally this had a short piece of rubber tubing that went between two sections of steel line.

Any opinions about using copper oil pressure line?

Thanks in advance.

 

[dklawson]

Copper can give you years of service. If the kit failed to say this, somewhere between the engine and the penetration in the firewall, take a small diameter can or other cylindrical item and wind the tubing around it several times. This coil of tubing between the engine and firewall creates a springy element that allows a bit of flexing and because the flexing isn't localized the work hardening of the copper is greatly delayed.

There are also gauge hose kits available from places like Summit which use stainless overbraid hose. They won't look original but they will last a long time.

 

[The_architect]

Thanks Doug,

The stainless steel hoses are an excellent suggestion. To do this I would just cut the copper pipe near the fittings, shove them into the proper size hose, and clamp them with some hose clamps?

I see the bulk steel hose at Summit (assume you are referring to Summit Racing) but kits for attaching fittings are eluding me.

Charlie

 

[dklawson]

The hose I recently installed on my project Spitfire is by "Longacre". It has a 1/8NPT male fitting on one end and a 4AN fitting on the other. The 4AN fitting includes a 1/8NPT female threaded coupler. With some Teflon tape that coupler screws on the back of the gauge, then the 4AN fitting screws into the coupler. That gives you a separable joint at the gauge end for service.

Here is one example:
https://www.summitracing.com/parts/LNG-45050/
If the link below works, it should take you to a list of several different kits having different hose lengths.
https://www.summitracing.com/search/?keyword=Longacre%20Gauge%20Supply%20Line%20Kits&dds=1

 

[The_architect]

Thanks, again Doug.

Unfortunately, I'm pretty sure on my Bugeye the fittings are Whitworth--at least they require a Whitworth wrench to remove. A 7/16 is too large, 3/8 too small. That's why I was wondering if I could just shove those copper pipes into the stainless steel tube and clamp them with some hose clamps.

Since no one else has weighed in here I am going to just assume I am worrying about nothing. I will just make some loops around the copper right near the engine and call it a day. It will probably outlast me.

You have just got to understand that there is nothing like finding almost a quart of oil has leaked onto your garage floor in a couple of minutes to put the fear of God in you. You would not want to know how close I came to toasting my engine. I wouldn't be caught dead with a nylon line on my car, either.

Charlie

 

[dklawson]

Well... the tap in the A-series block will be 1/8" pipe regardless of the across-flats dimensions of the fitting. There are arguments about whether or not that's 1/8NPT or 1/8BSP. Regardless, I've never had any problem putting 1/8NPT male fittings in A-series blocks. The back of the gauge is a straight 1/8 pipe thread. The actual seal is made with a fiber washer crushed between the bottom of the female tube fitting and the male stem on the back of the gauge. Once again, I've never had problems fitting 1/8NPT female fittings to the back of the gauges with the use of some Teflon tape to seal the threads.

I have nylon gauge line on our GT6. The first nylon line was there for 17 years. I literally just replaced it last weekend... not because it failed but because I fitted a new gauge and figured it was time. However, my first line was industrial nylon tubing with a much thicker wall than the stuff I just installed. You are right... the nylon gauge installation kits don't instill much confidence.

 

[The_architect]

Doug,
That explains a lot.

I do have those fiber washers you mentioned for the back of my gauge. Thanks again for your wisdom!
Best,
Charlie

 

[HAN8L1965]

Let me just say this,however you put this together it must be right or you are up s--- Creek as they say. Been there done that just drove past an event area recently and they were still using skimmers.

It is amazing how much oil will shoot out that little 1/8" line in a very short amount of time.

Mark

 

[The_architect]

Been there, when I broke the oil line the first time! Even a pinhole will dump a lot of oil in a few minutes.
Housekeeping hint: cement is great for soaking up oil--lots of surface area.