I need a little help. I have a 66 F100 with a FE. The block casting date is 411F and the heads are C4AE-G. This engine has been messed with over the years but it runs pretty well. I don't know anything about the previous work on the engine. I developed a lifter type tick at idle so I took off the valve cover on the bank with the noise. The head has adjustable rocker arms nearly identical to those on my 57 Bird 312. These yblocks all had solid lifters. I ran a feeler gauge through all the rockers, engine hot, and found them at .004 except one which was way loose and the adjuster nut is not very snug in the rocker. The push rods all have painted hash marks on the from 1 to 5 on each rod. I am confused. This engine doesn't sound like it has solids in it and my service manual shows FE heads with non adjustable rockers. Any insight into what I am dealing with would be greatly appreciated.

Mark Hebard

 

You have some kinda confusing animal in there don't ya. They sell "swollen" adjuster nuts for your rockers at www.dscmotorsport.com. They are .003 oversize. Your heads flow quite well compared to the later model heads. You shouldn't have any clearance with hydraulics and .004 is way to tight for solids. What is the casting number on the passenger side of the block? Many people switch to stock adjustable rockers so that may be of no concern.

 

To be clear, what I did was take a feeler guage and cranked the engine with a remote starter switch and ran the feeler through the valves just to get an idea what was happening. Now, I wonder how to adjust the valve lash. The business of swapping out pushrods is tedious. I remember an old mechanic that I apprenticed with for awhile used to quiet down GPD 460 remanufactured long blocks that kept coming back with a lifter noise by letting it idle and adjusting the rocker down until it just started to drop the cylinder and back it off a half turn. It worked and I never saw one come back but it always had me a little worried.

 

That is the messy way to adjust the rockers for a hydraulic cam but it works well. The way I do it is turn the engine until the number 1 intake valve is opened pretty far and adjust the exhaust rocker by tightening it until it just makes contact and then giving it another 1/2 turn. Open the exhaust to do the intake etc... If that one rocker was the only one making noise you should only need to adjust it but you can check the others of course to be sure if you want.

 

As Ratsmoker said m there's nothing unusual about having adjustable rockers with a hydraulic cam. I did the same thing back in the 80's with a GT 390, gives you a little more lift with the greater rocker ratio. I adjust them a little differently, doing the adjustment at TDC on each cylinder's firing stroke. At this Point both intake and exhaust valves are closed. I rotate the crank 1/4 turn and do each cylinder in the firing order. I mark the balancer or crank pulley in 4 spots, 90 degrees apart to be certain of turning it only 45 degrees each time. The adjustable factory rocker's adjustment screws have an interferance fit on the threads, and after repeated adjustments, they will "wear in " together and the threads get loose. I used to just replace the rockers that did this, but now a days that could be a little expensive ( I used to buy rockers at the local parts house then for $2 each) I adjust them for hydraulics by taking the slack out of the pushrod and then giving them another 1/2 turn.

 

Thanks for the info on adjustment. I was digging through the cab on this truck cleaning it out and found about 6 pushrods wrapped up behind the seat. Somebody has been dealing with this in the past. Forensic mechanics.

Mark Hebard