604 help

[racefan45]

Bought a used engine, ran it a couple times and it seemed good. Decided to change valve springs after checking some at 40. With new valve springs and zero lash, motor will not run. Had to open up lash to get it to crank. Motor very flat. What's going on?

[spray004]

How did you set your lash?

[racefan45]

The same way I always have. The same way brad at race1 describes in his FAQ.

[racefan45]

Anybody ever experienced this?

[zlssefi]

I know this sounds stupid but double check your plug wires. i did valve springs one time and obviously had to take out the spark plugs, when putting it back together i crossed a couple wires and it ran awful...

[brad hibbard]

.why are you at zero lash?----the description calls for 1/4 turn of preload and we have actually found that more can be beneficial and will soon change our recommendation if further testing continues to show posative results.

if you are at zero or have actual lash (clearence) --you may have already blown some clips out of the lifters-----you can look down in with a pen light and check the clips

our you sure this engine has not been cheated up and a set of solid lifters installed?


604 and 602 Valve Adjustment
■Roll the pushrod between your finger and thumb as if it were a cigar, at the same time begin tightening the adjuster nut.
■The INSTANT that you feel an increase in resistance to roll the pushrod -STOP- that is zero lash.
■NOTE this does require a certain amount of “feel” – by the time you finish your first set you will be a pro.
■Next: Tighten the adjuster nut 1/4 turn more.
■Next: Tighten the set screw (allen).
■Next: With your hex key (allen wrench) and your 5/8 wrench turn both into the stud another 1/16 to 1/8 turn, this secures the set screw from backing out.

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5. Positioning of the valve for adjustment
■When the intake valve is closing–ADJUST THE EXHAUST.
■When the exhaust valve just begins to open — ADJUST THE INTAKE
■There are other methods but we have found this to work on all engines and leaves less room for mistakes
■**NOTE** If you follow the firing order you will only have to turn the crank a 1/4 turn between valves once you get #1 in position.