Poly Oil Gauge Line Starts Fire!

62, built over 100 engines, first fire!
Oil gauges used to come with copper line.
To save 1.25$ they now come with poly line.
I spent extra time routing and tieing line away from headers.
During cam break in, 3000rpm, bout 5 min in, nice and hot, Flames.
Then the key off wouldn't kill the engine(No diode in GM alt yet).
Shorted out coil with ext to kill.
Took the shop fire ext and the 1 out of the truck to get fire out.
I figured I'd melted a line?
But upon investigation, I find the line blew out of the Ferrell and nut.
And yes nut was tight. Oil pressure @3K was around 60 warm, good for AMC.
I'll never use poly again, I'll pay the 12$ extra for the copper that should come with.
Glad it happened in shop bay, even though it damaged the ceiling slightly, if it would
Have happened on a test drive, it probably would burnt to ground?
A bunch of toasted wires to patch now, nothing major lost.
Oil makes a dang big hot fire.
Until it cooled I wasn't sure what killed the engine, was Nervous the bearings
Might have seized. Got lucky put a socket on ballencer and over she turned,
Only 2 qt low on oil, don't think any internal damage!
Please use copper line folks!

 

WOW
That sucks. I"ve got 3 jeeps with poly line
Glad you saved it

 

I've read threads on this site that recommend stainless overbraded poly instead of copper. Maybe someone remembers the source?

 

I've had a poly line break from fatigue. Don't care for it.

 

The only instance I can think of where I would use the poly oil pressure line would be on my mother in laws vehicle.......

 

LOL

 

And if you use copper line, put a few coils in it (like you see in steel brake lines under the master cylinder) to act as a shock absorber. If you don't the engine vibration will eventually cause it to break DAMHIK.
Even better, use a braided steel line.
Or even better, keep the oil in the engine & use a good quality electric gauge....

 

Another tip... run fuel hose over the copper line anywhere it *might* come in contact with metal. That stuff loves to pretend it’s a ground strap, and it doesn’t take much to arc through it and cause a hole.

 

x2

 

Its a little bit spendy but worth it IMO for peace of mind.
https://www.summitracing.com/parts/...MInIyIv46v6wIVa_DjBx1DXge7EAQYAiABEgLNT_D_BwE

 

Yes the Ferrell was in right flat end against nut, cone end into fitting, at least 1/4 in line in past Ferrell . Nut was tight, threads not distorted upon disassembly. It was a bastards size line and fitting from China, us pipe thread male X China poly compression. My other leftover poly kit parts would not fit it. It was a bad experiment on my part, I bought the cheapest 3 gauge kit off eBay from China, took 3 weeks to ship, looks nice but odd size fittings, water temp sender odd also . My 401, bout 500hp, blueprints oil pump runs 60psi warm, most AMC 8s don't get that high, it still should have bit the Ferrell into the tubbing and not blown .
Anyway it sounds real good, lol.

 

I’ve had good luck with copper. Been running it on my CJ-5 since 1989-90 but the run is long and it can distribute the flex over a very long distance. I do check it periodically. I’ve seen far too many failures with poly. Back then the electric gauges were not reliable and were not sealed well enough if they got wet. The new ones are far better.

 

X2 & X3 !

 

the PO did a mechanical oil gauge
it puked all over floor once . never again

 

I still prefer the instant and sensitive response of a mechanical gauge. It can tell me a lot more about a situation.

 

When did Gauges come with copper line. I can remember the SUN oil Pressure gauge I put in my 67 chevelle in 1978 having a nylon line. And so has every gauge I have used since I believe. On my Willys Build I am using a -3AN braided hose going too the Fuel pressure safety switch and the SW Oil pressure gauge.