I am updating my engine test stand with new gauges, the original electric oil gauge quit. I found a larger mechanical oil gauge and would like to use something other than the plastic feed line supplied with the gauge. Since it's a test stand and I lone it out occasionally , I would like a sturdier line. Will a -4 AN line with 1/4 ID effect the gauge reading? I don't think it will, it will hold plenty of oil ( 3' long ). Is there a better option? smaller ID line? Turbo feed lines are pretty cheap on the web, and would be easy to hook and unhook.
I didn't figure the size mattered other then the amount of oil it will hold. I will look into the -3 AN and copper. I want something that can go on and off with no issues.
I also hate the translucent plastic tubing, copper is OK but not the look I wanted. I stopped at my local Parker Hydraulic store and found some black “ plastic ” tubing that is normally used for pneumatic applications, spec’s out to 2-3,000 PSI and is not affected by petroleum based fluids. Works with the normal compression fittings, and almost disappears after installation. Win Win.
For the intended app, yeah braided AN will probably last a cpl hundred on-off uses and other than time to fill, I can't see it having an effect on pressure readings.
In my OT dune buggy I added an oil gauge to the dash and for ease of running the line used the plastic stuff. Since this is an off roader I covered the oil line with SS brake line gravel guard all the way from the engine to the gauge to protect it. It also doesn't look so cheap. Just an idea.
There can be a safety concern with the plastic lines because they do age and can split. It might not happen all the time but it does happen. I know this is for an engine stand but note that some gearheads make it a rule "no plastic oil pressure lines in the passenger compartment". Hot oil on your crotch nuggets is no fun. You might find something appropriately industrial looking and well functioning at your local hydraulic service store.
I hooked up the oil pressure gauge in my 57 back in 1964. I used copper line, and it still works great. I wonder if I had used plastic if it would have held up that long.
For a run stand I think I’d use plastic line, otherwise you have a rigid line dangling around when moving it or when you loan it out. You could easily coil up the plastic, tie wrap it for moves, etc. Yes they can come apart, I felt the warmth on my ankle before, but a stationary stand won’t see the same conditions a vehicle will.
I always wondered about that, so is the pressure from the line, not the oil itself, is what moves the needle. Ie an air gauge?
I’ve had plastic line my 1970 Mustang since 1978 and it’s never leaked a drop. Now having said that it doesn’t get driven much but I also don’t see any reason to change it either.
Everything I have lent out over the past 50 years inevitably comes back broken, modified, fixed or changed if it even comes back at all before I go looking for it. An engine hoist I lent to a racer back in the late 60s closed up his shop, sold the stuff and left. No more engine hoist. To answer your question braided line is just fine. Pat
My Dad used “ Air-equipped” ( might have misspelled it) on our 1959 Ford pick up back in 1962, worked great until we quit using the truck in about 1990! It is similar to this AN stuff. Bones
Well...yeah as long as the inside diameter is of a "reasonable" diameter. I doubt that a 2" inside diameter line would work very well. Even a .50" (-8) line would be slow to respond to things happening in the engine, slow to build pressure in the gauge on startup, the 1/2" dia. column of oil would act as a shock for sudden changes in the oil system. None of the above are good things Joe - Stick to -2 or -3 diameters. In order - 1 - Teflon (braided stainless) 2, 3 Copper or plastic. Both are pone to cracking / breaking, but will last if taken care of. Mike
The size of the line won't affect the pressure reading, though. A liquid in an enclosed volume is pretty good at having the same pressure everywhere...at least close enough that you couldn't notice any difference without some good instrumentation.
I've had it in my '73 Chevy pickup since new , original line . If installed correctly and routed away from heat and sharp edges , it will never be a problem .
I've had plastic line fail, where it went from the engine compartment, through the scuttle. The sun shone through the vents and weakened the plastic. So, if it is to be stored outside, I would recommend a metal pipe instead. I have a 1/8" copper line for the gauge on my car and it works fine. Made a three loop hoop by the engine to take up vibration and any movement.
If it’s going to be used on an engine stand and banged around, use a type of braided , small , hose! Copper will kink and can break, small plastic line can get next to something it shouldn’t! Braided line will last forever! Bones
I had - 6 AN on my Corvette race car. [because I had all the fittings/adaptors laying around] As @squirrel said it doesn't matter about the size because pressure is pressure and volume is volume. Larger lines are faster reacting , but this is really a moot point. But - 4 is can usually hande more pressure than the - 6 I used No matter what size you choose , all fluids and air in the line will equalize and not effect the reading on the gauge. If you want to get the air out of the line, just crack open the fitting at the gauge and crank the engine over until the air bleeds out. [not really needed]
I was at a track day years ago ,when a Holden V8 had plastic lines that melted/welded 30 psi into the line to the guage. As he proceeded down the Pit lane the engine was pumping oil out of the other half of the line. The track steward noticed oil all over the ground while waiting to go out on the track.
This sprayed oil all over my windshield. Would have been ok but it was raining and I had my wipers on.
This thread is about an engine test stand....so he probably doesn't have to worry about the line breaking and spewing oil on the track! Using AN line would be a good way to make things easier to deal with on the test stand. I'd probably just use plastic line, which is my go-to for temporary oil pressure gauge installations. I use copper tube on cars, though. One time having plastic tube baked by exhaust heat, then crack while driving, was enough for me.
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