The Stovebolt Site Forums The Shop Area Engine Shop How to Use a Vacuum Gauge

Very cool! Thanks (I just got my vacuum gauge... and only being 23, and this being my first old truck... useful information in that video!)

I have been trying to learn more about tuning my engine with a vacuum gauge.
I found your video quiet informative. Thanks for posting it.

Good video. I always use a vacuum gauge for tune ups. I still use a timing light. But I tend to rely more on the gauge for better accuracy on timing and carb settings.

I reset the carb & timing on my 49 216 tonight w/the vaccum gauge and this time I didn't retard the timing an inch as recommended and the truck runs a whole lot better. I didn't get any valve pinging under load so it seems to be happy with quite a bit of advance. The BB is nearly out of site in the timing hole.

Another issue I cleared up had to do w/the aftermarket air cleaner element I tried. Ends up it was too restrictive. The engine likes the OEM wiremesh much better. I'm looking to replace it w/an oil bath.

I'm also sold on useing the vaccum gauge method to tune single carb'ed engines.

The BB is a usually a good starting point for a timing setting but, for many reasons, it is unreliable as the final ignition-timing setting.

The vacuum gauge is the cheapest, easiest, and most consistently reliable way to adjust timing and carburetor mixture (and to get a quick/easy look at the overall condition of your engine). If you keep an eye on Harbor Freight sales, it is nice to have a vacuum gauge in your garage and in your truck.

One thing to note is that if you are doing a 4 banger (like a Go Devil engine) there will be a NORMAL 1-2 inch 'bounce'.. for any 4 banger. With only 4 intake valves there is a significant 'dead zone' between intakes opening.

Most of the vacuum videos/sites seem to center on 6-8cyl engines. If you have have a 4 cyl you *will* get a rapid, steady bounce only at idle.

Well to add my .02¢ the world is your oyster with these online videos. I never took automotive classes and now I am understanding how things work with these videos and how the old school of way to do things before life of the OBDII its just way too cool. After going thru the moss motors videos I started searching and found another set of tutorials from Eric the car guy. Now when you guys talk about certain procedures I am getting a clue. Thanks for posting the video, its way too cool.

I was so impressed w/how vaccum tuneing improved my 216 that I utilized it on my 72 Karmann Ghia w/a stock 1600cc dual port boxer engine and the readings, settings and operation was basically the same as with the inline 6. It improved that boxer 4 engine just like it did the inline 6. Perhaps inline 4's exhibit this bounce, as I didn't see it w/the boxer 4.
Dave

I set my 235 timing with a vacuum gauge and the engine runs great but now it is running considerably hotter then before I made the adjustment. I advanced it quite a bit but not past the point where I reached the highest vacuum. Is that normal or do I have another issue happening. I am going to set the timing back some to see how the temp changes.