let's check our multi-gauge sync meters, but how?

So, if I wanted to know if my 4 columns were all showing the same value, I could build something right? Maybe out of pvc, put a shopvac somewhere in the mix, thread a hole for a nipple, and start checking right?

Been done? Am I on the right track or way off?

 

I know it'll work, ill post results later in the week

 

Just go to the local auto parts store and pick up a 5-way vacuum manifold ("T"), and a Mity-Vac. Then you can connect all the hoses to the manifold, connect the Mity-Vac to the remaining port, and pull vacuum with it to verify that the four columns read the same.

 

exactly...
put all on the same vacuum source and they should read the same.

 

every service manual I've read that describes how to do a vac sync instructs to do as darkfibre noted.

plug in each to the same vac signal, one at a time and confirm that they all read the same.

Nothing wrong with doing so simultaneously as SQL suggests but be darn sure you don't have any vac leaks in your manifold setup rig thing or you'll be chasing phantoms.

 

Yes, it needs to be the same, I prefer to use 1 nipple to exclude three posibilities of trouble. I now have the cheapest method/idea. I'm gonna thread a hole in the plastic handle part of my shop vac! Its probably goin to be too much vacume so I'm either going to put a permanant hole in the hose or most likely use different size nipples to go up in diameter on the tubing then back down in diameter to the brtass nipple

 

Actually, no. Because if you have a vacuum leak in your manifold setup you'll see it as all four gauges creep together rather than holding the reading you've set with the MityVac. So a) the system would be self-testing, and b) even if you have a leak, it will provide useful information in that it will show whether all four gauges are reading the same as pressure increases.

 

While we are on this subject, who are some of the manufacturers of these multi-gauge sync meter systems and where can you purchase them? Have any of you had better results with one of another?

 

I've used the CarbTune, which is a pretty popular product. It works pretty well as long as you're careful to ensure it's hung correctly (straight), since it's very sensitive to being off vertical in any direction.

 

yamaman, "perfect" 100% vacuum, zero air, zero ANYTHING contained in an empty vessel is about -14psi at sea level. The issue can about never be too much "vacuum pressure". Various vacuum sources will just be able to flow more CFM

SQLguy. I mean if there is a leak in one line but not the others. I guess if ya just back the restrictors off then yeah it'll compensate but I just leave mine with a tiny amount of flutter and don't like fiddling with 'em so that didn't occur to me. And some woeful individuals have the bead style.

 

I still disagree. The only way you're going to see an imbalance when using a manifold to check the system is if you have a leak on the gauge side of a check valve. And if you do, that's exactly the kind of thing you'd be trying to find with this setup... but that would still be an issue with gauge and not with the manifold. Any leak in the manifold will be reflected across all gauges equally and will show when the manifold doesn't maintain the vacuum that you've set with the pump.

Testing with a MityVac is not like connecting to a running engine. You don't have high frequency swings in absolute pressure, you just have the fixed vacuum you've created with the pump. Restrictors will make zero difference here... they smooth out the pulses from a running engine, but they're still going to allow the same vacuum on both sides of the restrictor within a second or less.