New to WF, just bought a '98 TJ to replace an 87 YJ I sold after owning for 13 yrs. New Jeep is a 4.0, 5spd, Sahara. Background of Jeep - I am 3rd owner, 94K, Previous owner has gone through the head to try to fix upper end tick. New valve springs and lifters that I know if, not sure what else he replaced. Has aftermarket header, looks to be welded in middle, exhaust cut after the cat, (need to put muffler on and rest of exhaust pipe). Homemade by PO generic cone intake filter. Airraid throttle body spacer. I bought it knowing it had the ticking/ knocking upper end issue and low oil pressure (confirmed with my harbor freight gauge at almost 10psi at idle and 30 at higher RPM) and will replace the motor if it comes to that, but hard to believe it is shot at 94K.
SO, I have rebuilt the stock oil pump, but did not replace the pickup tube. Pan looked clean. Changed filter from STP to WIX, added 5 qts of 10W30, and a quart of slick 50. Same issue. OK pressure at cold, as soon as oil is warm, pressure drops to almost nothing and engine has a loud tick/knock in what sounds like the upper end/valvetrain. Engine runs fine, temp good at 210. Just the upper end noise and low/no oil pressure. Replaced the sending unit. Same deal. Going to find a deal on a HV oil pump and pickup tube, and go from there. Is my line of thought correct here? I think that the 10 PSI is too low at idle and hopefully that is where the tick issue is stemming from. Ideas? Thanks!