My '69 Chevelle has tell-tale lamps and I want gauges. I have been looking at buying a set of Green Line Stewart Warner's for it. I've looked at several of these oil pressure gauges on ebay and so far all of them have been electrically operated as opposed to mechanical. Since the meter has a band with oil pressure values, the needle will indicate oil pressure at the point of sender location. My original oil sender, currently in the box laying next to the dissassembled motor, is only an on / off switch. Right? In my thinking the factory sender is set to some predetermined minimum oil pressure, lets say 5psi... so as long as the oil pressure exceeds 5psi, the switch is open, when the oil pressure drops below 5psi, the switch closes, thereby making a ground for the tell-tale lamp to illuminate. If this is true and I bought one of these electrical oil pressure gauges I would also need to come up with a rheostat type sending unit. Right? The rheostat switch (sender) would flucuate the electrical current from the gauge thereby indicating oil pressure. It would operate basically like a gas gauge where the meter in the tank is an electrical ground and the amount of current being grounded is dependent on the level of fuel. I like the looks of the S&W gauges Yenko installed over others I've seen. I don't want to spend money on something that will not work right. I'm tired of that!

Thanks for your time and input..

You pretty much got it all right. Bottom line is that if you buy an electric oil pressure guage you also want to buy a compatible sender from the same manufacturer so everything works together.

Note that Autometer, from what I have seen, includes the sender with the guage.

Yes, that's the way it works. I would think that most (if not all) oil pressure gauges come with the sender, but I guess it doesn't hurt to verify that before you buy. I have never had any SW gauges, but as far as I know it's a good brand, equal to Autometer.

I would definitely suggest the electric variety. They cost a bit more, but I just can't stand the thought of a pressurized oil line under my dashboard. I think that some people here can confirm that it's not the greatest idea.

I have used both for some time, and they both work equally as well. I agree with Olle, if you get a slight oil leak, the carpet doesn't look so good afterwards.

Fred.

Yep, you have it right. You also know why you should install a "T" fitting, so you can keep the light and still operate the gauge.

Thanks for the feedback. The gauges I've seen for sell so far all stated that it was for the gauge only.
After I got back from the races over in Kennedale, while swimming the web, I found a company advertising the factory gauge package with no wiring harness modifications. You only need to buy their sending unit. For $250 it sounds like a pretty good deal. Anyone have any experience with this cluster?

And on the mechanical oil gauge, my plastic car has one. After I restored the cluster, and prepared to start it up, I covered everthing with plastic and rags. Luckily I had no leaks.

Thanks again ya'll

A point about electric versus mechanical...

Electric usually has a much more limited needle swing range than mechanical, something like 90 degrees versus 270 degrees. Makes indications more precise.

I also have a suspicion that mechanical guages react faster than electric. My electric Autometer moves very slowly. Years ago I had a Lucas guage in a Triumph and could see the guage bounce as the oil pump sucked air when the oil level was low in a corner.

As to leaks and such, that is largely dependent on how you plumb the guage. Use plastic tubing and leaks are much more likely than quality steel or copper lines.

If I went with guages, like mounted in the center console. how could I keep it where my lights on the dash still work?
this includes the temp guage and alt gauge also.

bluechevelless,
others will chime in but I would think that it would involve a second sending unit for the oil pressure and water temp guages. The alt reading could come from the back of the alt or the junction block.

Yep, that's it. Two sensor circuits on oil and water. One with a switching sensor and the other with a variable sensor.