Why does a 1977 Chevy 350 oil pressure gauge bounce now and then?

Answer 1

The question is very vague. By "bounce" do you mean that it falls, then returns? Does it jump high then normalize? Is it a sinlgle "bounce", or does it fluctuate for multiple cycles ar is slowly returns to equalibrium? Do you have an electronic or mechanical sender unit? It is possible that it is an electrical issue. I know that some older US cars have alternators with "slow" voltage regulators. The car switches between running off the battery vs the alternator. Sometimes there is a momentary lossof power as it is switching from one source to the other. I have experienced car stereos that momentarily turn off, then back on again whenever the voltage regulator kick over. The solution was to wire a capacitor in parallel, which acts as reserve power. Even if you have a mechanical gague, it could still be powered. Regardless, you need to determine whether it is you oil pressure, your sender, or your gague is to blame. Hook up a vlotage meter that has a needle (no digitals), and monitor your voltage. If there is a volage bounce at the same time, then you have your answer. Otherwise, try switching out components and see if the anomolie continues.