i have a 1985 f250 with a 460 and i have a question it has a tap in it. it on does it when you are going a steady speed does not do it when you start it up or when you gas on it. But when it does do this my oil pressure drops to about 40psi when i let off the gas the oil pressure accutly GOES UP!! any suggestions on this problem could it be the lifters? or maybe the mains? anything would help at this point!!!!
josh

 

What kind of milage do you have on the engine? If it a rebuild then the tap (more like a rattle) could be the pushrod are not set correctly. If your lifters were going bad the oil pressure wouldn't change at all. The mains or rods are more likely to cause the tapping noise. As for the oil pressure going up it sounds more like the relief valve is opening as you are driving then closing when you let off the gas. The pump isn't spinning as fast which reduces the amount of oil passing through it. Have you tried to use a broom handle places against the side of the block and the other end next your ear? Move it around the block and listen for the sound to get louder the closer you get to the source.

 

as far as i know its the orignal motor it has app. 120,000 on it. I change the oil on it this morning it had maybe 2500 miles on it and the oil was slugdy that came out. with the new oil in it it rattled just not as bad you idea sounds like a good one i'll try it in the morning thanks
josh
85 f250 460 c6
81 f250 351m c6

 

Did you use Quakers "high milage" motor oil? Just curious. I haven't heard if anyone had any luck with it or not. Let us know if the test comes up with anything.