Re: Idle vacuum - why only 10 inches?
 

I'd say my brakes work fine, though I'm sure they'd be better with 18" than with 11". But all of my vacuum accessories function acceptably.

In fact the only operational problems I'd like to improve on are the RPM drop when the AC compressor kicks in and the amount it heats at idle. Otherwise it performs admirably.

Re: Idle vacuum - why only 10 inches?
 

yeah, something is fishy. PB's don't work well with only 10" of vac. This is interesting.

Re: Idle vacuum - why only 10 inches?
 

I don't have a "before" to know the level of assist that I could expect with a higher level of vacuum, though. But we have a big vacuum reservoir and in most cases that'll trap and save any transient high vacuum periods like from startup, blipping the throttle, coasting down, and so on. So you're not actually only working with the idle vacuum, even with a big cam.

Maybe they'd be better with more?

Either way, I've checked with three gauges now, they agree...

Re: Idle vacuum - why only 10 inches?
 

Try adjusting the valves with the engine running. Go 1/4 to 1/2 turn pass clicking. I have seen vacuum increase when they where tighter that that.

Re: Idle vacuum - why only 10 inches?
 

Believe it or not my crate engine wasn't running right when I first installed it. I told one of the guys(master tech) at work how it was doing and he said the valves are too tight without even thinking about it. I was going to set the valves but couldn't rotate the motor and watch the valves by myself. I knew the factory sets them at one full turn so I just backed each valve off 1/2 turn and it runs great.
I told the master tech what I did and said I would go back and re-adjust them when I had some help but he said why, if it 's running good leave it alone.
I usually set valves with the motor running but this was a new motor and I spent a lot of time detailing under the hood.

Re: Idle vacuum - why only 10 inches?
 

I had an idle problem within 8 months of installing a new booster. My friend told me to check it. Did the soapy water spray with it and I was surprised, 8 month old lifetime warranty replacement was the culprit again.

I could not believe it. Dont know what to suspect at this point. :sumo: break out the can of whoop a$$

Re: Idle vacuum - why only 10 inches?
 

Did this problem ever get solved?

Re: Idle vacuum - why only 10 inches?
 

No, it hasn't. The truck failed emissions last year (finally). I rebuilt the carburetor, but haven't taken it to be tested yet. I just started full time school, as well as working full time weekends. So the truck's sitting in the side yard with a tender on the battery.

I think the only way this issue will ever be resolved is with a tear down and rebuild. As long as it passes emissions, and it remains a hobby vehicle, I'm not going to do a rebuild due to other obligations.

Thanks for asking! I don't like abandoned threads that are left open ended.:lol:

Re: Idle vacuum - why only 10 inches?
 

I was directing the question toward the OP

Re: Idle vacuum - why only 10 inches?
 

My apologies. I had written a similar post several years ago, and I thought your response was to that. I had participated, so I got the email alert.

Hopefully the OP sees this and responds.

Re: Idle vacuum - why only 10 inches?
 

No worries, I did not see that you had posted on the thread.