Missing again

[Texasdoc]

Exhaust open, intake close. That's the way I did it. But there were those few that didn't provide any resistance when I did that extra 1/4 turn.

Feels like it did when I had the previous miss. Ended up being two broken springs. Going to go all thru the electrical tonight. Will check springs and valve lash tomorrow. Confirmed timing. Both heads have a separate ground wire. Engine block grounded too. New MSD 6AL2 digital with clean power capacitor.

WBO2 reading about 15:1 at cruise at 3000rpm when it starts cutting out. MSD distributor, phased rotor, vacuum advance set to ported. Initial timing 20° with 34 total when vacuum disconnected.

[blykins]

Originally Posted by Texasdoc

Exhaust open, intake close. That's the way I did it. But there were those few that didn't provide any resistance when I did that extra 1/4 turn.

Feels like it did when I had the previous miss. Ended up being two broken springs. Going to go all thru the electrical tonight. Will check springs and valve lash tomorrow. Confirmed timing. Both heads have a separate ground wire. Engine block grounded too. New MSD 6AL2 digital with clean power capacitor.

WBO2 reading about 15:1 at cruise at 3000rpm when it starts cutting out. MSD distributor, phased distributor, vacuum advance set to ported. Initial timing 20° with 34 total when vacuum disconnected.

That's normal for the lifters to act like that. Some bleed off, while some stay pumped up, depending on where they are in the bore, and if there has been any load on them.

Did you check coil bind clearance while you had the heads off/apart?

[Texasdoc]

Originally Posted by blykins

That's normal for the lifters to act like that. Some bleed off, while some stay pumped up, depending on where they are in the bore, and if there has been any load on them.

Did you check coil bind clearance while you had the heads off/apart?

I did when the springs broke. I will go thru the exercise again.

If some bleed off and others don't, how do you know if your setting preload correctly? If they are still pumped up, some are collapsed, some are stuck, how do you know if it is being done right and all are uniform?

Is the lifter is supposed to be in the middle of its travel when set cold? Is it supposed to be bled off, pumped up, etc? Seems like you would need to set it while running to get them all uniform. If set while running do you increase the preload twist to compensate for the lifters being pumped up with oil pressure?

[blykins]

It's all by feel.

The most common mistake guys make is trying to "twist the pushrod" while trying to get to zero lash.

The best approach is to back the adjuster way out, then move the pushrod axially up and down while sneaking up on the adjuster until you don't feel any free-play anymore. You will feel when the pushrod touches the lifter plunger. Once you get to that point, you dial in your preload and lock it down.

A lifter can be pumped up or bled down and the pushrod seat in the lifter will be in the same spot. There is a spring under the plunger and it makes sure that the pushrod seat is always in the same spot, whether or not the lifter is "pumped up" and full of oil.

Preload is usually around .030-.050" of plunger depression. That's generally around a 1/4 to 1/2 turn of preload.

[rodneym]

For ****s and giggles, as soon as there's no play, lock 'em down with no preload.