Rb25det Compression Test

[Mr_GaZZa]

Hi every1,

just wanted a rough idea on whats normal compression for a GOOD condition RB engine STOCK 'say new'.

and whats if its higher? or lower then that mean

thanks

Gary

Edited October 5, 2007 by Mr_GaZZa

[Mr_GaZZa]

Okays well i did mine a few times and got averages of

160-165 across the board 'DRY"

=s whats standard?

because the manual says BELOW

RB25DET =

Standard Value_____________________Limit Value________________ Varinace Limit Between Cyclinders

(MPa/rpm){Kg/cm2/rpm}____________(MPa/rpm){Kg/cm2/rpm}____________(MPa/rpm){Kg/cm2/rpm}

1.20/300 {12.2/300}--------------------0.9/300 {0.90/300}---------------------0.10/300 {1.0/300}

Thanks GaZZa

NOTE just found that 165PSI = 11.6cm2 and 1.137 MPA

check here @ http://www.translatorscafe.com/cafe/units-...-psi-%5Bpsi%5D/

Edited October 5, 2007 by Mr_GaZZa

[R31Nismoid]

The rule is along as its simlar across the board, without a large variance, its ok.

Hard to say what a 'good' result is as many things can affect it.

So basically you have no variance, so the results are fine

[RB30-POWER]

do a leak down with the engine hot to determine actual engine condition. it will be far more indicative of engine health then a compression test.

[Shmee33]

Hey i bought a rb25det long motor with 150psi across all 6 cylnders, i took it to a machanic and he said its way way to low and he wont touch it but he thought its ment to be 195.

is he looking at the compression rate on a non turbo or what?

most people tell me that 150 is still good and the motor is about 80k old.

so can someone please tell me what the RB25DET is ment to be. thanks

thanks alex

[charlie25T]

rb25det come from the facor yat 172psi.......

so it depend on the condition of the motor.

150 seems fine but still low

mine s between 160 and 165 and i have dont 78k on the dash

[RB30-POWER]

was the engine warm when tested? if not the pistons haven't expanded and aren't sealing properly.

was it cranking with a good battery supply voltage? lower voltage = lower crank rpm = lower readings

cam belt could be out a tooth or anything to drop the reading a little. all stuff you would check before installing the engine.

sounds fine to me mate if its even across the board.

[Shmee33]

im not sure i wasnt there at the time.

also the mach was saying the error codes for my car.

he said, air flow meter, oxy sensor, oxy heat sensor, vomable timing unit and boost sensor is out. ecu said this

but they have been replaced in the past,

[race_snooze]

please remember that gauges are just that gauges!!!! they might be out by a bit, but 150 is fine.