lifter tap

[StinkinLincoln]

i got a slight tap at 1500rpms, cant hear it much past 2k b/c the motor/exhaust gets too loud or the tap just isnt loud enough.
it only does it under a load, and seems to be louder when i drive it vs just power breaking it to put a load on it.

i thought i fixed it, i moved my guideplates, the rocker arms on a couple studs seemed to be too far to the left or right, i tq. the studs back down to 55ft lbs. i noticed the pushrods had wear marks on the side, should i have the plates adjusted so that the pushrod doesnt touch?

wear marks ontop valve looks good.

i dont think its a header gasket leak, i tightened the bolts again.

i didnt hear it after i adjusted plates, had it reved in neutral all the way to 6k once. (looking for a vibration i had when i pulled the motor just a hair past 6k, thought it might have been valve float)

so i took it for a run, 1st gear pull to 6k, after the run i started hearing the tap again, so if anyone has ideas, let me know!

 

[R.J.]

How are you adjusting your rockers? Unless your perfectly confident about the way you did it, try this way:

This method of adjusting rockers will guarantee that the cam lobe of the cylinder that is being adjusted is at its lowest point.

With the piston at TDC, with both valves in the closed position, do the following:

The first thing you want to do is verify zero valve lash. The best way to do this is to wiggle the push rod up & down as you tighten the rocker arm nut. At the point where the push rod no longer moves up & down, That is zero lash. You now have a starting point for verifying “true” zero lash & the lifter pre-load.

When you adjust the valves you are setting the lifter pre-load, Pre-load is the amount of distance the push rod seat (or “cup”) moves away from the retaining clip.

To set true zero lash & the lifter pre-load, We are going to follow the “EO / IC” procedure.

What is “EO / IC?

EO, is Exhaust Opening; IC, is Intake Closing.

We have the piston at TDC (Both valves are in the closed position), Rotate the engine in the normal direction of rotation (clockwise, if you are facing the front of the engine).
You will see the exhaust valve just starting to open, stop rotating the engine & back off the intake rocker arm.(You are going to back off the rocker arm & re-verify for true zero lash, As you are now positively on the base circle of the camshaft whereas the previous lash adjustment was just a pretty close ballpark guess.) You will once again wiggle the push rod up & down as you tighten the rocker arm nut. When all up & down movement is gone, tighten the rocker arm nut ½ turn, tighten the hex head set screw until it bottoms out on the rocker stud, tighten the rocker arm nut ¼ additional turn. You have now set the lifter pre-load at .045”.

Rotate the engine, You will see the exhaust valve fully open & then close. Watching the intake valve that you just set, You will see it open, You want to keep rotating the engine until it fully opens & then starts to close. When it is almost closed, stop rotating the engine. Set the exhaust valve the same way you did the intake valve.

Move onto the next cylinder in the firing order…

 

[StinkinLincoln]

i used the method that requires 2 full crank revolutions and while running this go around. i can adjust rockers in my sleep now lol

im thinking i either have a exhaust leak or a dead lifter

 

[WHITE94COBRA]

There's not much that can go wrong with a lifter, they do get sticky, and that could cause a tap. Drop in some auto tranny fluid into the crankcase, maybe 1/2 quart, run the car for about 15 minutes, then change your oil. That will free up and sticky lifter. If your not comfortable using the ATF dump about 1/2 can of seafoam, works just about the same. I get better results from the ATF but the seafoam works well too.

Have you checked to see if you are getting a rocker just barely tapping the VC baffle?

 

[StinkinLincoln]

its not, i got the tall edelbrock covers. its only under a load that it does it.