i have a 1989 5.o i installed a trick flow stage one cam 499/510 lift 275/279 duration. i didn't replace the lifters, push rods or rockers. i did add gt40 heads with a 3 way valve job, had the heads surfaced and the trick flow spring upgrade kit installed at 1.800" as the paper said (those were done at the shop) first i didn't know anything about shimming so i just bolted the rockers down the car had a little bit of a high idle and ran a little warm didn't overheat though well i drove it for around 50 miles while trying to find the idle problem. them it started popping in the the intake towed it home and the number four cylinder had bent both push rods and broke the rocker arm bolt on the exhaust side next i replaced all push rods and ordered shims i shimmed all rockers with .30 shims runs great and at normal temp so i'm guessing without the shims the valves were open a little all the time but now i have a ticking noise so i checked that and on some the rockers a loose and wont get to 0 lash but without the shim it gets to tight before the bolt even gets hand tight any suggestions? Thanks.
Pedestal rockers aren't my favorite. I'm running the GT-40X 58cc and had similar problems. This is a combination of information I could find that was helpful for me.
Ford recommends a preload of 0.02 to 0.06". This means that once you set the pre-load and the oil pressure in the lifter bleeds down - there should be a gap of about 0.02 - 0.06" between the top of the oil cup/pushrod and the wire retainer. Basically the cup on top, inside the lifter, should be pushed down 0.02 - 0.06".
The 5/16-18 bolt on the pedestal rockers. One complete turn of the bolt will move down the rocker fulcrum 0.056". One half turn of the bolt will give 0.028". One quarter turn will give 0.014".
It also depends on the ratio rockers being used. 1.7s will be slightly different than 1.6s when the lifter bleeds down.
1.7 ratio: 1/2 turn gives 0.016" at the lifter. 3/4 turn gives 0.025". 1 turn gives 0.033". 1 - 1/4 turn gives me 0.041". 1 - 1/2 turns gives me 0.049".
1.6 ratio: 1/2 turn gives me 0.018" at the lifter. 3/4 gives me 0.026". 1 turn gives me 0.035". 1 - 1/4 turn gives me 0.044". 1 - 1/2 turn gives me 0.053"
The procedure for pedestal is a little different than stud. With studs you bring it to "0" lash then turn anywhere from 1/4 to 3/4 depending on your preference. With pedestals everything is a positive lock once bolted down. There is no small adjustments aside from shims or pushrods.
The consensus on the preload is 0.02 to 0.06". That would be anywhere from 3/4 - 1 - 1/2 turns from "0" lash.
I used a clicker torque wrench to around 13 ft. lbs., and a beam torque wrench to final torque. I do the lower torque at first so that I know how many turns until everything becomes firmly seated. Meaning the rocker fulcrum, pedestal, any shims and bolt is tight to the head. I don't care at first how much further it takes to get to full torque spec. I only care about the amount of rotation to get everything seated.
I tighten the 5/16 bolt by hand while using my fingers to spin the pushrod. As soon as I feel resistance on the pushrod I stop turning the bolt. That is my "0" lash. With the clicker torque wrench set to 13 ft. lbs. I put the torque wrench at 12 , 3 , 6 or 9 o'clock. Turn until everything is seated. If I got a 1/4 turn or less then I have too many shims. Removing the thin shim will bring the valve to within 1/2 - 3/4 of a turn. If I have a little more than 3/4 of a turn, adding a thin shim will bring it up to around 1/2 a turn. Once its set I torque to final spec of around 22 ft. lbs. with a beam type torque wrench. A little note. The FRPP pedestal shim kit. The shims actually measure 0.02" and 0.04". I guess the 0.03" and 0.06" has something to do with geometry and not the actual shim size.
I did each cylinder by firing order. 1-3-7-2-6-5-4-8. I have read a bunch of different ways. I looked in my Ford service manual for the 93 Mustang H.O., but couldn't find anything. Nothing on lifter preload either.