Compression test
Thread Starter
Racer
Joined: Feb 2012
Posts: 390
Likes: 1
From: Livonia MI
Compression test
I just did a compression test on my newly aquired 81. All my cylinders are within 5 psi of one another, which is great. But what is a typical reading for good compression? I was getting between 170 and 175 pounds.
Race Director
Joined: May 2006
Posts: 18,598
Likes: 2,540
I dont have the spec sheet for an 81 but that sounds correct for a low compression motor. Check this link.
http://forums.corvetteforum.com/c3-t...st-1981-a.html
http://forums.corvetteforum.com/c3-t...st-1981-a.html
Last edited by MelWff; Feb 12, 2012 at 11:33 AM.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 121
From: Millington Illinois
St. Jude Donor '08-'09
Somebody has been in there. 140-150 is typical. 175 is probably a rebuild with flat top pistons and/or smaller chamber heads or a cam swap to a more modern lobe design with an earlier actual intake closing point. Within 5 PSI is awesome.
that's high for an 81. Good for you!!! Now if you want a cam swap ,it might work well compared to others who tried on a low compression smog box
