Is my compression reading good or bad on sr20det ? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Ayonr1 · 03-21-2017, 07:13 PM

C1: 175 c2:175 c3:180 c4:175

Hoffman5982 · 03-21-2017, 07:23 PM

Good, you just have some carbon build up

***Future240*** · 03-22-2017, 01:09 PM

Quote:

Originally Posted by Hoffman5982

Good, you just have some carbon build up

What is the compression supposed to be? Ive seen some tests at like 150psi per cylinder.

di-devol · 03-22-2017, 02:28 PM

Says 128-156psi is the correct range.

Hoffman5982 · 03-22-2017, 08:39 PM

150psi is considered very good on SR and minimum on KA. Very good on KA would be what his readings are. Carbon buildup will make the numbers jump pretty high, so realistically he most likely has around 150 actual

gaz_moose · 03-26-2017, 10:41 AM

do you have aftermarket camshafts?

bfellini · 04-25-2017, 01:41 AM

Was the test performed on a fully warmed up engine, and were all the spark plugs removed and the throttle body fully opened while performing the test?

On my 87mm bored sr with step 2 264 cams, and 9.0:1 pistons, my compression #'s are 175 for all 4 cylinders on a fully warm engine... and I admit to slight carbon on the piston crowns...

Generally, as long as all the compression #'s are within the same range with a slight margin, as yours are, and above the FSM minimum, the engine is assumed healthy...

Carbon buildup can slightly raise compression, and can be seen visually by looking down the spark plug hole...

Is there an issue with your engine that prompted this thread?

03-21-2017, 07:13 PM	#1
Ayonr1 Join Date: Feb 2017 Location: California Posts: 16 Trader Rating: (0) Feedback Score: 0 reviews	Is my compression reading good or bad on sr20det ? C1: 175 c2:175 c3:180 c4:175

03-21-2017, 07:23 PM	#2
Hoffman5982 Nissanaholic! Join Date: Jan 2009 Location: Definitely NOT FL.... Age: 29 Posts: 2,491 Trader Rating: (25) Feedback Score: 25 reviews	Good, you just have some carbon build up __________________

03-22-2017, 02:28 PM	#4
di-devol Zilvia FREAK! Join Date: Jun 2010 Location: Woodinville Age: 39 Posts: 1,412 Trader Rating: (5) Feedback Score: 5 reviews	Says 128-156psi is the correct range. __________________

03-22-2017, 08:39 PM	#5
Hoffman5982 Nissanaholic! Join Date: Jan 2009 Location: Definitely NOT FL.... Age: 29 Posts: 2,491 Trader Rating: (25) Feedback Score: 25 reviews	150psi is considered very good on SR and minimum on KA. Very good on KA would be what his readings are. Carbon buildup will make the numbers jump pretty high, so realistically he most likely has around 150 actual __________________

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03-26-2017, 10:41 AM	#6
gaz_moose Zilvia Member Join Date: Mar 2008 Location: engerland Posts: 242 Trader Rating: (0) Feedback Score: 0 reviews	do you have aftermarket camshafts?

04-25-2017, 01:41 AM	#7
bfellini Zilvia Member Join Date: May 2005 Location: Eagle Rock, CA Posts: 167 Trader Rating: (6) Feedback Score: 6 reviews	Was the test performed on a fully warmed up engine, and were all the spark plugs removed and the throttle body fully opened while performing the test? On my 87mm bored sr with step 2 264 cams, and 9.0:1 pistons, my compression #'s are 175 for all 4 cylinders on a fully warm engine... and I admit to slight carbon on the piston crowns... Generally, as long as all the compression #'s are within the same range with a slight margin, as yours are, and above the FSM minimum, the engine is assumed healthy... Carbon buildup can slightly raise compression, and can be seen visually by looking down the spark plug hole... Is there an issue with your engine that prompted this thread?