plastic oil pressure line- careful- they break

[Owen L.]

Re: plastic oil pressure line- careful- they break

How does the steel line in a C2 big block differ from the small block? Length only?
I'm asking because I'm wondering which steel line kit would be the best fit for my '70 454.

Mark, not sure how they differ, but I think if you can get a new plastic line that is the better way to go.
GM changed for a reason?? Probably cost $$$.
50 years ago, I changed mine to copper/steel line only because that is all the Chevy dealer had at the time.
My car was my daily driver while in college.

So my '67 BB has the steel line with ~3" dia. coils at the firewall like a moonshine still. I assume this is to help the steel absorb the movement and vibrations of the engine so a work-hardening spot doesn't develop. If you were to go with steel, make sure to include the coils just due to the mere fact that GM engineers put it there for a reason. The repro steel oil pipes for C2 may not fit a C3 given the greater distance of the gauge in the center console. Zip states their non-coiled steel pipe is 40" but nothing on length of their coiled BB pipe.

I replaced the nylon line for my '72 BB a couple summers ago. Because I had the original metal (steel?) line and fittings at the block in good condition, I only ordered the small block replacement line and saved $20. Because the line must snake around the tighter quarters behind the dash to the center console, the nylon would certainly be easier to install.

[Richard G.]

Re: plastic oil pressure line- careful- they break

Years ago, decades is more accurate, driving my 1957 back from Canada I had my (aftermarket) nylon oil pressure line start leaking. I caught it before dumping all my oil onto I5. I was lucky it I didn't ruin the motor.
I replaced the line with steel on the way home. Vowed to never use plastic for this application again.
My 70's C10 also has a steel line on it from the factory.

[E B.]

Re: plastic oil pressure line- careful- they break

Mark, I bought mine from Paul Mazut Corvette 413-243-3439 ( correct material and diameter ). Ed

[Joe L.]

Re: plastic oil pressure line- careful- they break

I suppose if someone is really paranoid about the prospect of a ruptured nylon oil gauge line, one could retrofit a 1974 gauge and oil pressure sensor.

[Mark E.]

Re: plastic oil pressure line- careful- they break

I suppose if someone is really paranoid about the prospect of a ruptured nylon oil gauge line, one could retrofit a 1974 gauge and oil pressure sensor.

Why is a '74 gauge and sender needed?

[Joe L.]

[Justin S.]

Re: plastic oil pressure line- careful- they break

Joe,
Like a pressure transducer or RTD?

[Mark E.]

Re: plastic oil pressure line- careful- they break

For 1974 the oil pressure sensing system was converted to electronic. There was an engine mounted sensor and a gauge which was not directly oil pressure sensing. A wire connected the sensor and gauge. Wires don’t fracture and leak oil.

I didn't know about the change to an electric gauge. When swapping gauges, be aware that numerals had a greenish tint through about 1971; afterwards they were bluish

[Justin S.]

Re: plastic oil pressure line- careful- they break

I guess it changes resistance in the sending unit??

[Joe L.]

Re: plastic oil pressure line- careful- they break

I guess it changes resistance in the sending unit??

Justin------


I do not know the measurement methodology incorporated into the oil pressure sensor. However, this basic measurement system (i.e. engine mounted sensor connected electrically to the dash gauge) has been in use for many years. Corvette changed to this system for the 1974 model year and was one of, if not the, last. Most other cars converted earlier. No modern applications I know of use a direct acting oil pressure gauge, assuming they have a gauge, at all.

The same sort of thing was true for tachometers. Corvettes thru the 1974 model year used a mechanical tachometer. From 1975 onward it was electronic. Most other cars equipped with tachometers converted to electronic tachometers well before Corvette. By the way, while Corvettes used a mechanical tachometer, it was not a direct drive type as was often used in racing applications. A lot of folks think that pre-1975 Corvettes have a mechanical tachometer since they're akin to race cars. The cars may be but the tachometers are not.