I just did a compression test on my newly installed ls/vtec and it cam up with 180-175-190-190, I was told that they should be within 10% of each other, is this correct. well I am not drinking antifreeze and there does not seem to be a power loss. any ideas?

thanks
mike

 

your readings are all within 10% of each other. 10% of your highest reading is 19. your lowest reading is 175, which is 15 away from your highest reading of 190. 15 is less than 19, of which 19 is 10%. therefore, your compression test shows all 4 cylinders to be within 10% or less of each other.

a freshly broken in engine will usually pump over 200 per cylinder on a compression check.

yours sounds normal depending on it's mileage.

as for compression losses, you'll see one or more cylinders significantly lower than the others. this can be due to headgasket, or it can also be due to worn rings, scored sleeves, cracked piston, or bent/improperly seated valves. most of these will cause a significant drop in compression, usually 20% or more. chances are you just have normally worn rings/cylinders.

if you're not gettin cross contamination between your oil and coolant, or leaking from the headgasket, your headgasket probably isnt blown.


[Modified by drift, 8:48 AM 2/28/2003]

 

do a leak down to pinpoint the leak
your answers will be there

 

Just curious what the mileage on the motor and head are... also on the Vtec head did you get it vacuum and pressure tested before you put it on?

Also are you using stock internals ? and what kind of headbolts?


I have an LS/Vtec with stock internals and ARP head studs, and my compression test was 205-210 across the board...

 

65k on block and unknown on head, b16 bolts and stock valvetrain