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-   -   Compression test (https://www.zdriver.com/forums/300zx-z31-performance-technical-227/compression-test-35401/)

odebiyi 06-15-2012 05:27 PM
Compression test
 
CYL#1 -111
CYL#2 -105
CYL#3 -104
CYL#4 -111
CYL#5 -138
CYL#6 -103
Looks like Cylinder 5 took a crap, I pulled the spark plug and it had coolant and oil on it. Looks like head gasket job, any suggestions on the easiest way to get the job done?

AZ-ZBum 06-15-2012 08:20 PM
Umm... Higher numbers is better. Looks like you're low across the board EXCEPT for cylinder #5. I think your rings are very worn out if all your numbers are that low. Looks like it's more than a head gasket. Looks like it's a full rebuild.

hoov100 06-15-2012 11:14 PM
Originally Posted by AZ-ZBum (Post 312323)
Umm... Higher numbers is better. Looks like you're low across the board EXCEPT for cylinder #5. I think your rings are very worn out if all your numbers are that low. Looks like it's more than a head gasket. Looks like it's a full rebuild.
If he found coolant and oil on the plug with the highest reading I think the coolant and oil sealed the rings more then usual which gave the higher reading. I would say check the head gaskets first, worst comes to worst he's already a step ahead if he decides to rebuild the motor.

odebiyi 06-18-2012 08:35 PM
Does anyone know what the normal compression numbers generally are for these motors?

noboosts130 06-19-2012 07:02 PM
FSM for 87
Standard
NA 173
Turbo 165
Minimum
NA 128
Turbo 121
Differential limit 14 psi

odebiyi 06-20-2012 06:47 PM
Originally Posted by noboosts130 (Post 312513)
FSM for 87
Standard
NA 173
Turbo 165
Minimum
NA 128
Turbo 121
Differential limit 14 psi
Looks like I'm doing a rebuild, thanks


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