dalejr8ls1

iTrader: (1)

I have just finished on some head work and it started fine and idled great but I have a loud valvetrian noise..loud knocking. When I tightend the rockers, I kept turning while the valve spring compressed until it felt firm and tightend the bolt down then. What do I need to do to make sure the lifter preload is correct? Maybe did I torque the rockers too much? Can someone please make this issue clear to me..thanks guys.

vettenuts

iTrader: (4)

Lifter preload is fixed by the rocker stand and the pushrod length. Not sure I follow exactly what you did, but the manual tells you that with the number 1 piston at TDC, tighten exhaust rockers 1, 2, 7 & 8 and intake rockers 1, 3, 4 & 5. Now rotate crankshaft 1 turn and then tighten exhaust rockers 3, 4, 5 & 6 and intake rockers 2, 6, 7 & 8. You can tell your preload with a dial indicator on the rocker you are tightening.

Did you mill the heads or do anything that would require a different pushrod length?

HavATampa

iTrader: (49)

The procedure you described sounds like the old small block way of adjusting preload. The new engines have pedestal mounted rocker arms like vettenuts was saying. You torque them down to 22 ft. lbs. and let it go. If your pushrod length and swipe are correct, you are finished. Not sure why anyone would tear a motor apart without a decent repair manual.

eallanboggs

iTrader: (1)

With the OEM rockers you can't add extra preload because of the pedestal design, but you can damage threads or break off a bolt if you tighten too much.

Gary Z

The method you described is incorrect. Do not run your engine again until the rocker bolts are installed properly. The basic technique is to torque each bolt to 22 ft-lbs with the associated valve closed. Preload is determined by valvetrain dimensions and geometry.