Oilpressure line (copper) connect to engine

[FRANK]

Hi.

I bought a 1977 GMC C15 with 350/350. My Oil Pressure Gauge (mechanical) doesn't work, because it is not connected to the engine.

There are a oil pressure sending unit (one cable) in oil pressure port near distributer.

The unconnected copper line from oil pressure gauge is hanging out the firewall.

I need a picture / photo how is the copper line correct and original connect to engine.

Hope you understand me.

Best regards from germany.

 

[Charlie]

 

[donnieray]

Welcome. The copper line is after market and most people remove the sending unit and use a 1/8" npt fitting for the copper. 1/8" pipe thread on one side, 1/8"compression for the copper line side. You can rig them both to work.

 

[bucket]

Welcome. The copper line is after market and most people remove the sending unit and use a 1/8" npt fitting for the copper. 1/8" pipe thread on one side, 1/8"compression for the copper line side. You can rig them both to work.

'73-'77 have mechanical oil pressure gauges with a copper line.

The factory line screws into the block, at the location close to the distributor. I seem to remember the factory fitting style being different than the usual aftermarket setup, but I can't remember what exactly was different about it.

 

[73c20jim]

I'll try to get a picture.

 

[75gmck25]

I have the factory line and gauge on my '75, and you can see it in the attached picture. The metal line comes through the firewall rubber plug, and then there is a small brass fitting that is screwed together. The fitting is visible in the center of the picture. From there the hard line is protected by a rubber sleeve, and is then routed down to the block and screwed in. I think the line may be made of steel, not copper, since it does not bend easily.

The line has a threaded fitting that just screws directly into the hole in the block where your sending unit is now installed. There is a notch in the back of the intake manifold to allow space for the screw in fitting.

Bruce

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[donnieray]

'73-'77 have mechanical oil pressure gauges with a copper line.

The factory line screws into the block, at the location close to the distributor. I seem to remember the factory fitting style being different than the usual aftermarket setup, but I can't remember what exactly was different about it.

I never knew that. I've only dealt with mid eighties trucks.

 

[highdesertrange]

I have a mechanical gauge on mine. you need a NPT to 1/8 compression fitting on the block. it looks like this,

https://www.grainger.com/product/2P...2237!&ef_id=W2JbMAAABTZf@iD9:20180823004731:s

I can't recall what size NPT a the moment but I believe it's 3/8. highdesertranger

 

[hoagster]

Here's the locaton on the engine

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[hoagster]

Do you need them, I have all the connections as you can see in the second picture, the top line (not curly one) is the line that goes thru the firewall. Let me know, cost you some postage!