2010 at the Hammond Barn

[Phil Waterman]

Hi Bob

Can not remember are your filters mounted open end up or down? Reason I ask is that on my 261 in Beauty the filter is mounted open or screw-on end up and I always fill it with oil when I change it. In that position any air in the filter is immediately pushed through by the oil coming in. So as long as the engine is pumping oil it should flow through OK.

I tried an experiment with the 235 engine on the test stand mounting spin on filter closed end up screw-on end down. This leaves an air bubble trapped in the top of the filter. No evident effect on the oil pressure accept when the engine stops the oil pressure bleed down is considerably longer. Mounting the filter this way though makes changing them a mess.

Going up the hill should not be a problem as the pump and pick up should be in the deep end of the oil pan. It would be going down that the oil could flow away from the pickup. I retried my truck on steep down grade low RPM no noticeable pressure change. My oil pressure drop may only occur at full song on the engine 2800-3000 rpm. So I suspect that it just the amount of oil these pumps are pushing up into the engine.

As we discussed before the big spin on filters and the 1/2" lines running to them do act as an oil cooler. Takes a long time to get the oil up to operating temp.

Keep us posted on your carb angle experiments. Good idea using diesel fuel I was just going to use gas, but your way is safer, but how much more or less viscus is diesel and will that change how it goes past the float valve?