I read up on this on a Ford Six forum a while back, but I have yet to do it on my old Ford. It's done on them because the harmonic balancer has a tendency to turn and your timing marks aren't where they're supposed to be.

 

Anyway, months ago I bought a Sun Econno meter. Like this one.

 

It's just a vacuum gauge you put on the dash to tell you when to back off the throttle.

I bought it to put on my old ford, but I drive the loyale more so I figured I'd throw it on there today.

At idle it sets at 25-26 hg. Is that about right? I've yet to drive it, but I will tomorrow to work and see how things go.

Anyway, the idea behind setting the timing with a vacuum gauge is that each engine is different and worn to different specs, etc, etc. And to set the timing where the engine makes the most vacuum at idle.

Sound right???

It's been a long long time since I tuned one with a vg. If memory serves, you would start with the timing retarded a bit, advance it until you reached max vacuum, then retard it a bit until it just starts to drop off. If you left it at max it would ping.

 

To tell you the truth, I quickly learned to time by ear since the vacuum gauge movement was so slight compared to large movements of the distributor. It's too easy to be off by several degrees. It will get you in the ballpark, just fine tune by ear.

 

The best use for a vg besides reminding you to keep your foot out of it, is in diagnosing engine problems. If you develop a misfire, a steady gauge will tell you it's ignition related. A jumping needle indicates a valve train or compression problem. A needle that easily goes to 0 or even + on modest acceleration indicates a stopped up exhaust.

 

So many people are quick to start replacing parts like plugs and wires without doing basic diagnostic tests first. A vacuum gauge check is one of those tests and a true time and money saver if done first. Having one plumbed in to your dash full time should be standard equipment.

 

PS 25-26 hg at idle is too high. It should be right at the yellow/green 20hg line at idle, tranny in neutral. It should also be at zero with the engine off. The gauge needs to be calibrated.