OK I searched the preload topic until my eyes went blurry, and havent been able to find anything that relates to my exact problem,I have a 400 that was running fairly well (no lifter noise) that blew a head gasket. I put on a new fel-pro blue gasket and buttoned everything up.When I fire the engine the lifters all pump oil, but rattle like mad even after setting each rocker bolt to 25 ft/lb when at its closed position.What could be the problem??Is the new head gasket thickness moving the heads away from the lifters creating not enough preload ?? Can these rockers be adjusted while the engine is running like the old Olds motors?? I have read many posts about these rockers being non adjustable, but would putting more torque than 25 ft/lbs make a difference? I dont want to just start cranking them down just to bend pushrods ect...Any input would be great...thanks

 

This is the stock valve train right?
Was anything done to the heads?
Did you put the heads on the same side they came off?
Did you re-use the old lifters (did they ever come out of the holes, did you mix them up? Did you mix up the rockers or push rods?

 

all stock,no head work everything back in the original location,lifters never came out,just changed the head gasket and put every thing back

 

That is odd. The only adjustment to these is to shim between the mounting boss and the fulcrum... but this reduces pre-load, which is not your problem. There is no adjustment-on-the-fly ala GM. I do not think it is the head gasket. Pre-load was .020 to .060 before (in ford we trust?) and the Fel-pro gasket can't be that much different. Are you sure the crank-case is full of oil, does the pressure come up to normal? All the fulcrums are flat to the head bosses and not canted by accident? You are getting oil pumping out each pushrod (just confirming)?.

This is messy but will ID the rattling holes. Lay a couple of red rags accross the valve train on one side to minimize flying oil. Start enging. Press down on rocker on pushrod side carefully and firmly while running, it will act a lot quieter if it has slop it in when you do this. Repeat for other side.

All else I can think of is to measure all the pre-loads and see how many are off and how badly. Generally, too much preload will break stuff so be glad you don't have that problem anyway! This is very odd. I would try to fiqure out what changed before I started ordering longer pushrods. Something went back together different, you'll have to find it or satisfy yourself everything is Ok as is.

GL!

 

After the truck gets warm, if you take the valve cover off and turn the motor to where both valves on a cylinder are closed, do the push rods on that cylinder feel sloppy? Can you feel play in the rocker arms?

 

How did you determine that the valve was truly closed when you set the pre-load. The cam must be on the base circle. This occurs on the compression stroke. There is a proceedure mentioned in another recent thread for doing this.

Check the other threads and determine if you had the valves closed, or run the procedure to be sure.

 

i dont know if this would have anything to do with it, but the rockers had these oil deflecters that was right underneath the bolt. maybe you have a couple of them backwards. it should be facing the push rod side.

 

a question- what if the gasket was thicker than the one he took out?

 

Any gasket variation should be within the tolerance that the preload take care of.

 

Just for clarity there is no preload adjustment from the factory. Just torque down the bolt and it doesn't really matter if the valve is closed or not. How long did you let the engine run? It may take a couple of minutes for the lifters to pump up if they drained. Are you sure the push rods are seated in the lifter?

 

if it make s u feal ne better mine done that to me after a top end rebuild but only on hole???? hasnt hurt nething yet. i was told that it happens sometimes that they just wont pump up the same and i shouldnt worry about it. that and im in the process of building me a motor so mine should hold out till then

 

A cleaner way to work on the rocker arms with the cover off is to take a 12 pack box and open it up flat, then bend it so it fits inside the gasket surface on the head. Then take it off and cut a hole in it long enough to see all the rockers and wide enough to get your hand in. This way the oil hits the underside of the box and stays inside the top of the head making clean up alot easier. Product of drinking,wrenching,and not wanting to get oil in our beer.