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Hey paul did you ever use a compression guage to set the cam degree?
 

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urban rat said:
Hey paul did you ever use a compression guage to set the cam degree?
Short answer: Yes.
 

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You just need an adjustable cam sprocket and a compression gauge. You advance or retard the cam to fine tune the compression. It doesn't take the place of using a degree wheel and you can't fix a mismatched setup. I also have a test stand where I do initial setup, leak down and cranking compression tests prior to break in. This is where dial everything in before it goes in the car. It's easier than leaning over the fender and much easier to fix something prior to installation.

There's more to properly getting pressure readings than you might think.
The popular belief is to crank away until the pressure gets as high as possible.
This is counter productive since the number of pumping cycles can be different depending on individual cylinder sealing. An asthmatic and an athlete can both inflate a balloon to the same pressure but one will do it quicker than the other. So if you if you think your 145 psi cranking compression is "ok" but it took 20 cranks to get there you have a problem!

Compression checklist​
  • Remove all the plugs to reduce starter load.
  • Block open the carb so air can get in
  • Make sure the battery is charged or better yet have a charger on the battery
  • Remove the ignition B+ lead to distributor
  • A remote starter button will make the job much easier
  • Crank each cylinder four "puffs" ONLY
  • Record the results in your log book.
  • Check compression before and after a cam change and every time you change plugs
I don't want to give away all my personal secrets, but basically an engine is first an air pump. The better it pumps air the more power potential it has. A vacuum gauge, compression tester and leak down gauge are essential for analyzing pumping efficiency. You have to know how to interpret the results and how the valve train and moving piston creates the pressure differential that moves and compresses air.

Getting lot's of fuel into an engine is easy. Getting lot's of air to go in without a supercharger is hard.
 
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