LT-4 Compression
Race Director
Joined: Dec 2002
Posts: 13,348
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
Re: LT-4 Compression (QIKSLVR)
My computations say the ideal theoretical reading will be 142psi.
The GM manual says the lowest should not be less than 70% of the highest and that the lowest should not be lower than 100psi.
Larry
code5coupe
:seeya
[Modified by rocco16, 6:20 PM 5/22/2004]
The GM manual says the lowest should not be less than 70% of the highest and that the lowest should not be lower than 100psi.
Larry
code5coupe
:seeya
[Modified by rocco16, 6:20 PM 5/22/2004]
Thread Starter
Instructor
Joined: Jul 2002
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From: Lakewood Ranch FL
Re: LT-4 Compression (rocco16)
Larry - -
Thanks for the info. I recently had a 60,000 mi service done on my '96 LT-4 Collector Edition and had the technician run a compression test. Cylinder #1 has the lowest compression of 140 PSI & cylinder #5 has the highest at 155 PSI. Cyliners #2, 3 & 7 are at 150 PSI and #4, 6 & 8 are at 145 PSI. By my calculations 140 PSI for cylinder #1 is slightly greater than 90% of the highest reading.
By the way how did you come up with the theoritical computation of 142 PSI?
Thanks for the info. I recently had a 60,000 mi service done on my '96 LT-4 Collector Edition and had the technician run a compression test. Cylinder #1 has the lowest compression of 140 PSI & cylinder #5 has the highest at 155 PSI. Cyliners #2, 3 & 7 are at 150 PSI and #4, 6 & 8 are at 145 PSI. By my calculations 140 PSI for cylinder #1 is slightly greater than 90% of the highest reading.
By the way how did you come up with the theoritical computation of 142 PSI?
Race Director
Joined: Dec 2002
Posts: 13,348
Likes: 233
From: SCMR Rat Pack'r Charter Member..Great Bend KS
Re: LT-4 Compression (QIKSLVR)
QIK,
Compression ratio (10.67:1) times standard atmospheric pressure at sea level (14.7) minus 14.7. I can't guarantee the accuracy, but it's close enough for me.
Sounds like your readings are excellent...all very close. Remember, carbon build-up can increase a cylinder's compression over time. Just don't ask me how much!!!
Larry
code5coupe
:seeya
Compression ratio (10.67:1) times standard atmospheric pressure at sea level (14.7) minus 14.7. I can't guarantee the accuracy, but it's close enough for me.
Sounds like your readings are excellent...all very close. Remember, carbon build-up can increase a cylinder's compression over time. Just don't ask me how much!!!
Larry
code5coupe
:seeya
