I decided to find the source of a ticking/clattering that I have heard in the top driver's side of my engine for awhile and discovered that that the pushrod on the exhaust valve of the cylinder closest to the driver's firewall(#8 I believe?) had come apart at the end that connects to the rocker. I have now decided to replace the lifters, pushrods and rocker arms. I upgraded to Pro Form roller rockers. (just went with regular ol' Federal Mogul lifters and Comp Cams Hi Energy 3 piece pushrods to keep costs down) The heads on this motor are from a mid to late 80's Mustang and are pedestal type rockers instead of the pressed in stud type that were originally on this motor. I have read all kinds of advice about how to properly install rocker arms. I know I want both valves closed when I torque the arm down. Does anybody have any advice about installing rockers/lifters/pushrods? Also, does anyone know the torque spec on the bolts that hold the rocker arm down? Thanks!
Pretty sure the specs for pedestal mount rockers were just mentioned in a thread this week, I forget which one, but i bet a search would turn it up.
DOH! Figures...I knew I shoulda done a search before I posted... I'll still take any advice anyone has...
I didn't find exactly the information I was looking for. Does anyone know the torque spec for the pedestal style rocker arms? Is there any special way to torque them besides making sure the cam is on the heel of the cylinder that I am torquing?
Pretty sure its 25ft-lbs, and I just bolt them down without regard to position. Ill double check on that spec though... Being that youre changing so much stuff, youll probably want to check preload. Might have to shim them, but hopefully not. EDIT: 18-25ft-lbs
I start with #1 cylinder, turn the motor over to where the exhaust valve just starts to open- set the intake valve. Now turn the motor over to where the intake valve is just about closed- set the exhaust. When I do pedestal rockers, after I've got the motor turned to where I'm ready to adjust a valve, I back the bolt off, pull that pushrod out and clean it. Then I paint the top part with a felt pen, set the pushrod back in the lifter and set the rocker on top, but DONT tighten the bolt. Now lay a scribe flat on the valve cover rail of the head and very lightly scribe a mark on the pushrod where you marked with the pen. Now tighten the rocker bolt and scribe another mark on the pushrod. The difference between the two marks is the ammount of preload you have. Now you can either grind the pedestal or add shims to adjust that valve. It sounds complicated, but once you do a couple of valves its pretty easy. Hope this helps.
chilton's 64-71: specs 0.180" clearance valve tip to rocker tip, on flat of cam lobe, with lifter fully compressed. hydraulic lifers. this is how my valve lash turned out on roller rockers w/ roush 180 heads. (i used method below, checked with this, eyeballed/checked wear pattern to approximate for correct geometry) alternate method: lifter fully "pumped up" on flat of cam, adjust for "zero lash" (just touching) turn in an additional 1/2 to 1 turn. (i used 3/4 turn). hydraulic lifter are a "little" more forgiving than solid, due to how they function. My spec on rocker stud to head attachment was 55ft/lbs. yours may be a little different. make sure to thread seal. some go into intake runners/water jacket/exh. coat top of stud well with oil befor installing rockers/locks I also recomend locking adjuster nuts (with the little allen bolt inside them) good luck and good move.
With the cylinder at TDC compression stroke, slowly tighten the bolt until zero lash, you can't spin the pushrod with your fingers. Torque bolt to 18-20 ft lbs. This should happen from 1/4 to 1 full turn from zero lash. If you reach that torque within that turning range, lifter preload should be correct (.020" - .060"). This is normally done with no oil in the lifters. If your lifters are filled with oil the settings won't be right the first time until after the lifters bleed down. Once you do have them set, if you take things apart later, all you have to do is torque the bolts 18 - 20 ft lbs and go. Unless, of course, you change cam, lifters pushrods, gasket type, etc.
Here's a way that a friend of mine uses. I'm the mechanic on a race car owned by a guy named Ed Sneva, he does it like this: take an old distributor cap, drill a hole between the coil terminal and the spark plug terminal for all eight cylinders( this hole is a window to look thru and see which way the rotor points). Now put the cap on your distributor and turn the motor over till you can see the tip of the rotor line up with the spark plug wire terminal for # 1 cylinder. Adjust the valves for that cylinder. Now you can adjust the valves in the firing order while only turning the motor a small amount each time. Very fast method with very repeatable results. Ed is the only guy I've ever seen do it this way, and I used to argue that it was'nt really the right way to do valves. But he's always done it like this and I guess it worked well enough to help his son Tom Sneva win a couple of races, one at some place called Indy.....
Thanks for the replies! The more I look at these pedestal rockers the more I think that it doesn't matter where the valve is when they are tightened. The bolt goes into the head through the middle of the rocker...there is no adjusting other than adding shims under the rocker or changing the pushrod length. Does it really matter where the valve is when you torque the bolt down? In this case 20 ft lbs is 20 ft lbs, right? Assuming the preload is correct of course...just thinking out loud here...
That's right, but the very first time you have to adjust them on the base of the cam so you know the preload is correct. After that, just torque them down, as long as your lifters aren't pumped up with oil. It could take more than 20 ft lbs to force the oil out of a lifter.
Gotcha. Since I am putting in new lifters, the oil will not be a problem. Once I verify the preload, torque 'em down. Thanks again!
