Hello.

I have an '88 GL. Dash oil pressure gauge doesn't work. I just dropped a younger motor in it.  New motor had good oil pressure when I pulled it out of another car about ten years ago. Motor was stored in garage and wrapped up. Should be fine. I even put new o-rings in the oil pump. But I would still like to "see" my oil pressure just once if I can but I don't want to buy a mechanical gauge since I'm on a low budget. My Polaris engineer neighbor says I should be able to figure it out with my multi-meter by reading either a voltage value or a resistance value at the sending unit and then translating that info into my oil pressure. Some kind of factory spec? I figure one of you folks would know what he's talking about. I started it today and seemed like the valve train or something was a little loud but it might just be in my head. I'm off-grid so I don't always have my computer on but will reply when I can.

BTW old motor had 333,000 on it and still running strong but starting to smoke.

Old engine probably just needs new valve stem seals. 

And yes, you can use your multi meter to read the oil pressure. You just need to know the values of the voltage/amps/ohms you’re seeing on your multimeter. 

An original workshop manual should have those values recorded somewhere - or a member from here might be able to record their values to what’s seen on their pressure gauge. Not exactly accurate but a good indication for you. 

As for noisy drivetrain, the lifters probably need more time to properly pump up, that or they’ll always be noisy. 

Cheers 

Bennie

Yes sir. Thank you. You are right about the valve stem seals. Once they leak enough to where it's only starting on three cylinders for a minute, I have to do something because that just won't cut it in the winter around here. I might look into changing them on the old motor. But I think that the newer motor will outlast the rest of the car this time around. The rest of my spare parts are already on it. And as someone on here told me once, I'm operating off a dead platform. Sure like these cars though and where there's a will there's a way.

Late reply, but old gen oem oil pressure senders are bimetal type, and can't be read with a meter.  Aftermarket rheostat type sending units can be read with a meter.  If you have the factory sending unit, you'll need a compatible working dash gauge, or to use a mechanical gauge for testing.