C2 Oil Pressure Line

[Ralph E.]

Re: C2 Oil Pressure Line

Not to add more confusion:
JG states Small Blocks - Copper, Big Block Steel

[William O.]

Re: C2 Oil Pressure Line

I just checked my BB, its steel. Not copper plated steel.

So what is correct?

[William O.]

Re: You are dead wrong!!!

Question:

Is the JG wrong? what is correct?

[Duke W.]

Re: C2 Oil Pressure Line

I'm the original owner of my SWC, and with very few exceptions have done all the work that's ever been performed on it. My original oil pressure gage line is copper plated steel and the part number in the AIM is 3718812. I doubt if this part changed for '64, so what is the part number in your '64 AIM?

To anyone else who can help out, what's the part number in later AIMs. (Hint: look is Section 12 - Electrical.)

Any mechanical engineer or anyone who has ever taken a basic materials science course KNOWS that you do not use copper tubing in a vibration environment!

I don't know how long improper copper oil pressure gage lines have been out there, but they ARE out there,, and they should all be replaced with proper copper plated steel parts ASAP. At best a broken oil pressure line is going to make a helluva mess and leave you stranded. At worse it may cost you and engine!

NCRS manuals are put together by dedicated folks who do their utmost to correctly describe configurations. To someone not familiar with materials science and what materials are suitable for various applications, it would be excusable for them to conclude that the oil pressure sender line is copper because that's what it APPEARS to be from casual observation. The only way to check for underlying steel below the copper plating is to test with a magnet.

Duke

[Duke W.]

Re: C2 Oil Pressure Line

No, it just looks like copper. See my post, above.

Duke

[William O.]

Re: C2 Oil Pressure Line

So the SB is steel with a copper coating, and the BB is the same, or is it just steel?

My BB is steel, looks like steel, has a correct loop at the firewall with no copper color, is this correct, shall I change it to steel with copper coating? In your option, what will be correct?

Thanks for the all the posts.

Bill

[Joe L.]

Re: C2 Oil Pressure Line

Duke----

The part number was GM #3718812 throughout the mid-year period for small blocks. So, the part number is not going to help us with this issue. Since this was a PRODUCTION-only part number, that also reduces other information that might be available.

I agree that copper is not a tubing that is really suitable for just about any automotive use. The vehicle codes of most states make the use of copper tubing for brake or fuel lines illegal.

The part that really mystifies me about this situation is why did they choose a copper plate for this tube? Copper plating is very unusual for automotive applications. So, if they were to use copper plating for this tube, then they must have had a very good reason for that selection. It's not as if things were routinely plated copper. I just can't figure out what the reason would be. In addition, the copper plated tube would imply to the average mechanic of the era that the tube was copper and that's what they'd replace it with, especially since any replacement tube had to be made-up. So, by plating the tube with copper, it's almost like they were asking for trouble with no, apparent, benefit. TBW steel tubing was used for most other tubing applications, so why not this one? Of course, I'm not sure if TBW tubing is available in this small size.

[Duke W.]

Re: C2 Oil Pressure Line

The '67 L-68 I helped judged yesterday was deemed to have a correct oil pressure gage line. It was magnetic (I checked) and appeared to be copper plated. I didn't check the book for proper surface appearance, but the two senior judges that I was assisting had no question about its appearance.

What does the JG say for your particular year/engine configuration?

Remember that NCRS judging is based on whether a part "appears" to be original, so a copper tube will pass this test unless the judge possesses the system knowledge to know it should be copper plated steel and checks it with a magnet.
IMO all judging manuals should be updated to require that the oil pressure sending line be checked with a magnet to ensure that the base material is steel, which would be a great service to members and help them avoid a possible disaster.

Duke

[Duke W.]

That's the $64,000 question

Thanks for verifying that the 3718812 oil pressure sending line was used on all C2 small blocks. The part number leads me to believe that it may have also been used on C1s, so this issue may not be strictly limited to C2s, and may include some C3s too.

I've racked my brain as to why this steel line is copper plated rather than cadmium or zinc similar to fuel and brake lines. Cad plating can cause hydrogen embrittlement so bolts or other highly stressed plated parts must be baked at suitable time and temperature following plating to remove the hydrogen. I can't argue that the copper plating was used to get around this requirement because the pressure in the line probably does not stress the material that highly. Brake line pressures can approach 1000 psi! So it remains a mystery to me.

1. The original oil pressure sending line on my SWC that I know to be original since I'm the original owner and there was never a need to remove it until I pulled the engine for overall is copper plated steel.

2. Copper is not an appropriate material to use in a vibration environment because of the work hardening issue. ANY engineer knows that!

If you have a copper oil pressure sender line - verified by a magnet that it is non-magnetic, I can think of two possibilities.

1. The GM supplier slipped in some bogus copper lines that were installed at St. Louis - a possibility I highly doubt.

2. What you think is the original oil pressure sending line is not, but a bogus (and unsafe) reproduction.

Duke

[William O.]

Re: C2 Oil Pressure Line

The JG manual for BB states "steel with brass fittings" , with a typical coiled loop(s) at the firewall.

I understand if the parts look original, they should judge it correctly.

My desire is to make my car as original it can be with all of the correct parts and appearance.

Thanks for all of you help.

Bill

[Ralph E.]

Copper Plated Steel Lines

Duke,
Thanks for your help with this post. I have one of those vendor supplied copper lines. The day I got it I question the vendor. They immediately pointed out to me the JG states SB are copper, BB are steel. The line removed was copper plated steel as verified by a magnet. I have been concerned about this since I installed the copper line. You can bet it will be changed.
It would be interesting to find out why they used copper plated steel. I thought it was because the copper gave the line flexibilty, while the steel gave helped withstand hardening caused by flexing.

[Floyd #21606]

Re: C2 Oil Pressure Line

Guys,
I just checked my 65 fuelie oil pressure line it is a copper coated steel line.
I have had my vert since December 1965.
Hope this helps.
Floyd,
65 Fuelie

[Stephen W.]

Re: Copper Plated Steel Lines

Just a guess here but would the copper provide a better corrosion protection because it is so soft it can be flexed without fracturing when bent? Does copper have any self healing qualities to it? Or would it just provide a better sealing ability?

[Duke W.]

Re: Copper Plated Steel Lines

Small diameter fresh copper tubing is quite ductile and easy to form, which is why is it popular, and those who don't know better have been known to use copper tubing in applications where it's totallly unsuitable, and any kind of vibration environment is inappropiate, so it doesn't belong in any kind of transportation equipment.

It is a great material for home water piping!

Small diameter steel tubing of the type used for the oil pressure line is also fairly ductile, so it can be easily formed, but it doesn't work harden and become brittle in service like copper.

As to why this steel line was copper plated instead of a more conventional cadmium or zinc plating, I am at a loss to explain.

Unfortunately, NCRS has probably unwittingly contributed to this bad situation because the line "appears" to be copper, and those who developed the JGs did not check known originals with a magnet. Most are knowledgeable enthusiasts, not materials engineers, so it's understandable that such and error can get into the judging documents, but I hope NCRS will do something to recify this ASAP.

Of the six C2s that I helped judge yesterday, four had what I considered to be the original lines based on the aging that was apparent on visual inspection. The '76 L-68 probably had a replacement line as the entire car appeared to be "fully restored" and everything looked like new. The one SB that had the copper line looked suspicious to me, and the magnet confirmed my suspicion. I believe that if you place a new copper line next to a copper plated steel line, the copper line with have a shinier and smoother surface patina.

Duke

[Duke W.]

Re: Copper Plated Steel Lines

I can't say. Most platings are "self healing" to one degree or another - ions will migrate to exposed areas of steel and renew the protection somewhat. As far as the ductility of the plating itself is concerned I don't know. Brake and fuel lines have some fairly sharp bends and as far as I know they are formed after plating.

Duke