Oil Pressure Drop

[DakotaZ]

I have a 72 240Z and recently I've noticed that the oil pressure drops down to around 10-15 lbs at idle, then goes up to 30-35 while on the hiway:mad: I know this isn't normal, I've been told that it could be the bearings. What do the Z experts think, and is it safe to drive as long as I'm getting some kind of pressure.

[Daniel]

You're assuming that the gauge is correct.I have seen dirty oil/oilfilters cause that.Also the oil sending unit (which is screwed into your block down below the spark plugs)gets old/worn/plugged up.It gives false info to the gauge.To test the gauge disconnect the wire from the sending unit and use alligator clip jumper or such and ground the wire.Switch on your key. The gauge should go to maximum and hold there.If the gauge doesn't go max or doesn't hold max let me know and we'll discuss gauge repair.Sending units are cheap and easy to swap.Have fun!! Daniel

[2ManyZs]

He is right, the sending unit is always the first place to look. The oil pressure gauges were never the most accurate in the world because of them. You could take it out and try a mechanical gauge in the port. This way you will know exactly what kind of pressure you have. Most mechanical gauges will come with an 1/8 inch fitting that will screw right in. If you still have low oil pressure check your pump and drive gear, it may save you time and money.

[Rev.Victor Webb]

Another place to check is the fuel. If the carbs are dumping too much fuel it may wash past the rings causing low pressure. I recently purchased a '70 240 that had this problem. An easy way to check is to feel the oil consistancy,if it's watery that would be a problem. By the way, I am new to the site, so Hello.

[AxtellZ]

there was a way-too-deep-for-me discussion about oil pressure on the Z-list a few weeks ago. General consensus in the end:

5 to 15 lbs at idle are just fine, and under load around 30 to 60lb.

Most likely the sender is faulty anyway, but seems to me most zcars are not deficient in keeping their oil flowing. Try pulling the oil cap in the valve cover while its running, and peek in at the cam with a little flashlight. Most likely she'll be smothered in oil...

Good luck- i'd keep an eye on it, but doesn't sound like you have to much to worry about.