O T Ford oil pressure fluxes

Only saw one engine that had fluctuating oil pressure. It was a Mack bobtail trash truck with about 500k miles. As the engine rotated, the not so worn parts would pass by the very worn parts and as they did the pressure would drop and return for the other part of the cycle. Ticking is low oil pressure in lifters caused probably by worn pistons therein.

Stepping on the gas forces the engine bearings against one worn out side of the respective crank or camshaft leaving a large space on the other side allowing for more oil to excape as compared to when you let off and let the crank/cam center.

My advice; get an engine overhaul. Your truck has earned it.

Mark

Like the others have said, put a mechanical gauge on it to verify your actual pressure.

But, I think you have a gauge problem rather than a pressure glitch. It almost sounds as though the sender was meant for a system that was equipped with a warning light instead of a gauge.

If you are sure it is the correct sender, perhaps the wiper is bad and the circuit is going open when the pressure comes up at 'off idle'.

Allan

I think that Big Fred is right on with his idea of installing a mechanical oil pressure guage at least temporarily to see whether the oil pressure is actually dropping or not.

When I was young and doing a fair bit of mechanic work, your symptoms were considered to be classic signs of worn thrust bearings on the crankshaft. The theory that my "shade tree" mechanic buddies and I had was that the crankshaft thrusted to the rear of the engine when accelerating and then settled back to the middle of the thrust bearing range when it reached a less stressful point of operation. When it was thrusted to the rear, the oil would escape around the bearings rather than being forced through the oil passages in the crankshaft, thus reducing the oil pressure.

Who knows whether our theory was right or not, but I do know that I saw excessive bearing wear in engines that exhibited this symptom.

Good luck,

Tom in TN