i have an 83 f250 that i just put a fresh motor in. put about 2000 miles on then it developed a lifter noise. the exhaust pass. side 3rd hole back. i went through and put another new lifter in and the same noise. inspected all the parts ,even switched them around. with the cover off and the engine running i can back the rocker all the way off then start to tighten then the noise will quite for a couple of seconds. it does this untill the rocker is tight. then shortly the noise is back. the block was checked and serviced at a local machine shop. the heads were rebuilt. the rocker oils good at start up. oil pressure is 20 at idle. i'm out of ideas. tell me what you think. thanks, sid

 

I thought the lifters on the engines were hydraulic .. but anyway some thoughts. Is the push tube bent? or is the valve stem bent? Is the hole for the lube of the hydraulic lifter plugged and not letting oil to the lifter? Is it the lifter or the injector acting up under pressure? Just some thoughts. Hope I can steer you in the direction to get it running right.

 

Cam lobe out of spec? Bent/worn out pushrod?

 

You could try switching taht injector to one off the other bank,that will eliminate the injector......or not.Could very well be tha injector.

 

the injectors tested good. the lifters are hyd. roller. when i tighten the rocker it depresses the inner plunger that stops the noise. as soon as the plunger adjusts to the new height the noise comes back. the valve train has been inspected three times. nothing bent or wore. i would think if the lifter bore oil hole was pluged the rocker would be dry. it's not. pretty soon there is going to be a truck in iowa for sale cheap! despite the mounds of cash i dumped in this thing. i just want a good old reliable truck. thanks for your input. sid

 

Does the noise go away when you loosen and then retighten the intake valve?

 

no. just the exhaust valve.

 

try checking the rocker arm.

 

Agreed/rocker arm. They're alum and if you see wear on the underside get new ones- fast before you lose the engine. I replaced several blocks because of rocker arm failures that allowed the lifter guide to break, the lifter to get crossways in the bore and the cam to chew it up & ruin the block. Had a couple locked so hard that I could not get them out of the bore. And torque the retainer bolts to the proper torque, not by feel. There is a reason for the torque values in the manual. Remote possibility is a piston pin slap. David

 

the heads i used are the newer ones. i don't have the aluminum rocker hold downs. these are steel. i have inspected the rocker arm and even switched them. no change. thanks, sid

 

If you are sure the valve guides are OK it sounds like a camshaft problem. If the profile is worn it may still open the valve and fire the cylinder but make noise once it self adjusts. It would be bouncing the lifter as soon as the valve hits the seat.
Pull the valley cover off, remove the lifter and inspect the cam. You may have to pull it out in order to measure the wear.