Oil pressure question...I promise it's not another "who likes what' thread!

beanhead said

Okay, aside from the 'funtime with screen names show' does anyone believe it's better to wait until more miles are on before going synthetic? I remember an old builder telling me 'not before 5000 miles' but that's been years..
And thanks fish but the relief spring only controls the ceiling, my issue is with the floor so-to-speak. I'm not getting into bypass with the 10-40, the 15-50 was actually bringing 5 more psi up top which, I don't think was opening the valve either. It *should* (there's that word again) be a 72-psi spring.

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The floor is controlled by the pump volume, the ceiling is controlled by the relief spring. Sounds to me like you are on the edge of having too many leaks for a HV pump to keep up with. You can increase the pressure by using a heavier oil, but that doesn't actually provide more lubrication for the engine. It just makes the pressure on the gauge higher since the same pump is now trying harder to push the heavy stuff thru the engine.

With a positive displacement pump like on a Mopar engine the volume of oil pumped is fixed. So at 900 rpm idle speed you are pumping X gph regardless of oil weight. The pressure on the gauge is a resistance to flow so higher pressure at the same RPM doesn't mean more flow or better lubrication. In fact, higher pressure from a heavier oil could result in less lubrication in critical areas in cold weather. Shouldn't be a problem with your type of car though.

You might be okay as is. If you want to run a thin oil and push more of it thru the engine then you'll need an even higher volume pump such as the Milodon pump.