Idle vacuum - why only 10 inches?

[geezer#99]

Did you degree in the cam when installed?
How deep do you have your lifter preload?
Is tdc #1 verified with the balancer/timing tab?

[MikeB]

Originally Posted by geezer#99

Did you degree in the cam when installed?
How deep do you have your lifter preload?
Is tdc #1 verified with the balancer/timing tab?

Ah, yes. Too much lifter preload could cause valves not to fully seat, which could cause low manifold vacuum. Pretty easy to do if you're not familiar with the procedure and/or there's no oil in the lifters.

[davepl]

Originally Posted by MikeB

Ah, yes. Too much lifter preload could cause valves not to fully seat, which could cause low manifold vacuum. Pretty easy to do if you're not familiar with the procedure and/or there's no oil in the lifters.

It "don't mean much", but it was actually built by a retired Winston Cup (NASCAR) engine builder who retired from North Carolina up to my area. And he's been an engine builder and machinist for decades. So I figure he knows how to set the valves.

And I watched.

They also smoke-tested the motor with a Snapon machine that injects smoke and basically does a leak test, and it was one of the tightest they've tested. But that only rules out a leak from intake to crankcase/valley, not bad lash.

If it were the valves, it'd show up on a leakdown test too, would it not? I'd have to check a couple of different cylinders to be sure.

[MikeB]

Originally Posted by davepl

It...was actually built by a retired Winston Cup (NASCAR) engine builder who retired from North Carolina up to my area. And he's been an engine builder and machinist for decades. So I figure he knows how to set the valves.

Probably true. Have you talked to him about the low manifold vacuum?