Another Compression Test: Cause For Concern?
Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
Another Compression Test: Cause For Concern?
The motor is a 396sbc, 11.2:1, DCR 8.30, 244@.050HR cam. Motor was warm, throttle open and all plugs removed. All cylinders went to 140-150psi on the first crank and reached max on 5-6 cranks.
1- 220 3- 210 5- 240 7- 204
2- 210 4- 205 6- 220 8- 215.
I redid several cylinders to make sure the readings were correct. The car runs fine on 93 octane with 34 degrees total timing and 10 degrees of vacuum advance. Should I be concerned about the 240psi on #5? The motor has around 900 miles on it.
1- 220 3- 210 5- 240 7- 204
2- 210 4- 205 6- 220 8- 215.
I redid several cylinders to make sure the readings were correct. The car runs fine on 93 octane with 34 degrees total timing and 10 degrees of vacuum advance. Should I be concerned about the 240psi on #5? The motor has around 900 miles on it.
Last edited by nastee383; Oct 22, 2008 at 01:29 PM.
Burning Brakes
Joined: Feb 2003
Posts: 1,128
Likes: 4
From: Upland Ca
At 900 miles the rings should be broke in. I would double check the lash then give it another few hundred miles and recheck. If no or little change it's time to do a leak down test and find out where it's leaking.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Don't know if this will help or not but I just did mine yesterday in my 427ci with 10.5 or so to 1 and 248/254 duration cam and all mine came in at 210-220 psi.
Check them again with the exact same number of cranks, I use 10 cranks cause I can't see the gauge because my remote starter is a PIA to hook up
BTW my last three motors were all in the 210-230 psi range, this is where you want to be to make power
Check them again with the exact same number of cranks, I use 10 cranks cause I can't see the gauge because my remote starter is a PIA to hook up
BTW my last three motors were all in the 210-230 psi range, this is where you want to be to make power
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Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
