As usual,

stumbled across this while looking for something else.

Check Your Engine?s Health: With a Vacuum Gauge | Tuner University

Describes interpretation of vacuum gauge readings -- including the seemingly bizarre ones.

You oldsters/shade tree mechanics prob already know this stuff, but it's something many of the younger generations weren't necessarily schooled on.

Sometimes we forget about the power of simple technology.

Pretty neat that you can interpret so much from such a simple tool and measurement....

 

Great find, derf. You should make a sticky out of this one. I'm having an idle problem on my PT Cruiser and I think someone replaced the timing belt and didn't get it spot on. Seems to be a timing issue according to my vacuum gauge. It's reading 15" of vacuum off the intake port for the PCV.

 

check the actual degrees of intake opening BTDC and the exhaust closing ATDC and they should be near equal usually less than 10 degrees on stock stuff. I found that the timing markers were not in a good position and when resetting them as I described my Saturn runs perfect with 20 inches of vacuum

 

I have no way to calculate the degree of each cam. Can you suggest something that won't involve purchasing a special tool of some kind? I am flat assed broke.

 

I think the degree wheel cost me $5 and I bought it at my local speed shop You can see when the valve moves off the seat and approximate the degrees with the wheel. Once you see it done you will agree it is very simple and very good to do this.

 

Interesting...I wonder if there was/is a reason saturn did this....

 

I was using a crescent wrench on the cam bolt and watching valve opening to measure this,certainly not precise but effective and set the cam timing chain where the valve opening was near 0 Just a little BTDC for the intake to open and just a little ATDC for the exhaust to close. On mine that was around 6 degrees but I did find that according to the service manual and setting the cam timing my car ran very poor and after my method I was pleased Gotta believe that all cam gears are not created equal

 

Entirely possible, sir.