New Lifters and Valvetrain Noise

[DattMtn]

Posted Friday at 10:33 AM

I have recently gotten my engine back together with a new cam (Comp Cams kit: K68-201-4), with new intake and exhaust valves that I have lapped into place. No milling no decking was done. There were issues with the lifters that I received, a full tenth under on the diameter. I figured the lifters shouldn't be sloppy in their bores! Finally got the correct diameter lifters 0.904" (Sealed Power: HT-2011) in it and put the rest of the motor back together. After doing the break in run of 30min at 2K rippums with high zinc purple break in oil, I have noticed that there is a lot of clatter in the top end and upon further inspection there is slop in some of the rocker arms. Is there a way that I would be able to test these new lifters without pulling the head again? What would be the cause of roughly 4 rockers to have slop? If I wiped the cam that would typically be on the nose of the cam not on the heel where I am seeing the closed valve rocker slop. It's interesting that the if it's the pushrod length, while it is okay on some of the cylinders. I am fairly certain I am making good oil pressure as I ran it with the valve cover off for a second and it sprayed oil hard all over the engine bay (factory oil gauge shows pressure). I would very much appreciate any input you have and set me on the right path. 

[Moses Ludel]

DattMtn...All testing can be done without removing the cylinder head...Key off, coil wire pulled, rotate the crankshaft to bring #1 piston to TDC on the compression stroke.  Be certain that the rocker arms are in their correct positions;  the rocker tips should center over their valve stems.

Check the valve rockers for play.  If you loosen the rocker bolts, the plungers in the lifters will extend to full height.  Wiggle the pushrod to confirm whether there is play or clearance; this is easier if you rotate the pushrod back and forth gently with your fingers, lifting up and down to confirm clearance. 

Very slowly, rotate the rocker bolt down until the play just disappears.  Do not go further or you will be compressing the lifter plunger.  If you go too far, back off the bolt until the plunger has extended to full height again.  Each lifter has an internal spring to expand the plunger height until the cup is against the retainer clip (plunger fully extended).

If you have a dial indicator, place it at the top of the rocker arm, directly over the pushrod.  Turn the rocker bolt down very slowly, watching the dial indicator to confirm how far down the lifter plunger drops.  (This is the lifter preload.)  Full preload takes place when the rocker bolt bottoms snugly.

Do this at each cylinder with its piston at TDC, both valves closed and the camshaft lobes on their heels.  See whether each lifter has normal lifter preload.  If they each do, you should have no lifter noise.    

If you do have noise, either the lifters are not getting enough oil, or they are bleeding down.  A new set of lifters is seldom defective and bleeding down.  Be sure that the new camshaft lobes look normal and not worn on their peaks. 

To confirm that the lifters get oil, after you tighten each rocker, you should feel distinct pressure/resistance in the lifter.  (Apply heavy thumb pressure at the rocker's pushrod end.)  Resistance is normal and means that oil is in the plunger and the lifter check valve works properly.  Do not attempt to charge the lubrication system or fill lifters with oil when the pushrods and rocker arms are loose.

If the lifter's plunger drops considerably when you apply pressure above the pushrod, the lifter likely has no oil in it or the lifter check valve is defective.  If oiling is okay and the cam lobes are okay, there could be an issue with the pushrod lengths.  You can measure lifter cup to rocker arm lengths with a CompCams pushrod gauge.  Allow for desired preload.  (Determine the correct length pushrod for zero clearance plus the desired preload.)  Compare this length to the current pushrod's length.  Do this with each lifter on the heel of its cam lobe.

All this can be done with the cylinder head still in place.  See the discussion on the CompCams tool and setting proper clearance.  Read from the 12-23-2018 exchange downward... 

Moses