1969 Oil pressure/gauge problem. Help

[Brian M.]

Re: 1969 Oil pressure/gauge problem. Help

The Oil I'm using is

Brad Penn Racing oil

SAE10W30

This oil contains a high level of Zinc Dialkyldithiophoshate

[Terry M.]

Re: 1969 Oil pressure/gauge problem. Help

I remember a recent thread on this board from someone who had issues with his oil pressure gauge. I think his problem was low reading across the scale. Replacing the plastic line solved his problem, but the cause was traced to a lack of the supporting thimble in the plastic line. When the B-nut was tightened against the compression sleeve without the supporting thimble inside the line it crushed the line enough to restrict the oil flow. That could be your problem.

The GM replacement oil lines used to come with the nuts, compression rings and thimbles installed on the line. I don't know how the current parts come, and someone unfamiliar with how all these pieces go together might not notice a missing thimble(s).

It would be relatively (note that word) easy to unscrew the B-nut and inspect the line for the thimble at the engine end. It would be a gold plated b)*&h to do it at the gauge end.

[Brian M.]

Re: 1969 Oil pressure/gauge problem. Help

Terry

Great feedback. It may be as you said a "gold plated b)*&h" to check out, but I'll not be happy until I solve the problem.

Thanks
Brian

[Jack H.]

Re: 1969 Oil pressure/gauge problem. Help

I agree with Dick on the cleaning issue. I built a small/simple fixture to test oil pressure gauges. It's simply a short hose with fittings to mate the oil press gauge on one end and my shop air compressor on the other end.

I fill the short hose with hydraulic oil after connecting it to the target oil pressure gauge. Then I connect oil filled gauge/adaptor hose to my shop air compressor with the assy hanging down so the hydraulic fluid won't/can't run back into the air compressor.

Once connected, vary the outlet air pressure of the compressor and watch for the target oil pressure needle to move in lock-step. OFTEN, I see gauges that are off quite a bit at the low end of the dial but work nicely at, say, 20-40 lbs.

With those that are 'off', it's about a 50-50 shot that they'll clean up when the needle movement on the back of the gauge is sprayed with carb cleaner, blown dry with compressed air and the key movement interface points are freshly oiled and the gauge then re-exercised on my air compressor with attaching fixture...

[Terry M.]

Re: 1969 Oil pressure/gauge problem. Help

Terry

Great feedback. It may be as you said a "gold plated b)*&h" to check out, but I'll not be happy until I solve the problem.

Thanks
Brian

Start with the one at the engine. If that one doesn't have the thimble I think you (or someone) will have to change the line. I don't think the thimble is available separately, and even if it were inserting it after the line is crushed I would think is not very easy.

[Brian M.]

Re: 1969 Oil pressure/gauge problem. Help

Joe
I was also suprised when the dealer said the hot engine oil pressure at idle was 25-30lbs. Seemed high to me given the gauge reading.

Thanks
Brian

[Brian M.]

Re: 1969 Oil pressure/gauge problem. Help

Jack

I'm going take the original gauge and run similar tests on it.

I just didn't think it was the gauge, because the original and replacement gauge acted in a similar fashion.

Thanks
Brian

[Domenic T.]

Re: 1969 Oil pressure/gauge problem. Help

For what it is worth,
The aircraft industry uses copper on oil lines and they have to deal with severe vibration and movement.

They require a loop to dampen the movement.


I would keep it stock, but in a pinch copper will work just fine.

DOM

[Brian M.]

Re: 1969 Oil pressure/gauge problem. Help

Thanks Dom

When I've used a copper line before (old cars but not Corvettes) I've always added multiple loops to dampen vibrations. Your comment reaffirms the method I'd use if I vary from stock. I'll try to keep it stock.


Not that matters but it's a nice 1969 Red/Blk/Blk convertible with side-pipes.