22 replies to this topic

[E-AT CIVIC]

i did a compression test on my civic si 1987 and the result are: 150psi on 4 cyl
i think its a little low but i dont understand,the car have only 43000 miles on it... in the service manual it say that the minimum specs are 156 psi so i really dont understand why the compression are so low for that mileage! the timing mark are good also and doesnt burn any oil or coolant... whats the problem ??

[gtpilot]

Was the engine hot or cold? Clearance tighten when the engine is warm...

Did you open the throttle wide open to do the test? The engine will build more pressure @ WOT...

Were the spark plugs removed from all cylinders when you did the test? The engine spins faster without having to generate compression in the other cylinders...

Kirk

[gkiing]

d15a3 has only 8.7:1 so it shouldn't be very high..

perfect for turboing though

[chedda_j]

Cylinder Compression (at 300rpm/wide open throttle)

Nominal

~~~~~Carbed
~~~~~~~1300cc only = 171 psi
~~~~~~~All others = 164 psi

~~~~~Fuel Injected
~~~~~~~Si only = 156 psi
~~~~~~~All others = 185 psi

Minimum

~~~~~Carbed
~~~~~~~1300cc only = 142 psi
~~~~~~~All others = 135 psi

~~~~~Fuel Injected
~~~~~~~Si only = 128 psi
~~~~~~~All others = 135 psi

Maximum variation between cylinders = 28 psi

[E-AT CIVIC]

Was the engine hot or cold?  Clearance tighten when the engine is warm...

Did you open the throttle wide open to do the test?  The engine will build more pressure @ WOT...

Were the spark plugs removed from all cylinders when you did the test?  The engine spins faster without having to generate compression in the other cylinders...

Kirk

<{POST_SNAPBACK}>

yeah i do it like you said ,hot,WOT,all spark plug removed!!

[E-AT CIVIC]

Cylinder Compression (at 300rpm/wide open throttle)

Nominal

~~~~~Carbed
~~~~~~~1300cc only = 171 psi
~~~~~~~All others = 164 psi

~~~~~Fuel Injected
~~~~~~~Si only = 156 psi
~~~~~~~All others = 185 psi

Minimum

~~~~~Carbed
~~~~~~~1300cc only = 142 psi
~~~~~~~All others = 135 psi

~~~~~Fuel Injected
~~~~~~~Si only = 128 psi
~~~~~~~All others = 135 psi

Maximum variation between cylinders = 28 psi

<{POST_SNAPBACK}>

are you sure of your specs??

[crazi-85crx]

those do look about right. which means you have nothing to worry about

[BigOrange]

seems real good to me!!! I have a leaky head gasket, 197,xxx miles and mine still pulls like a banshie!

[chedda_j]

seems real good to me!!! I have a leaky head gasket, 197,xxx miles and mine still pulls like a banshie!

<{POST_SNAPBACK}>

Thats a civic for ya.

K as for the specs i got them directly out of my haynes.

[Screech]

the posted specs look right, I really should have compress tested my old engine before pulling it, even with 256K on it the thing ran awesome.

[3gencivic]

ok im confused.
i did a test on my carbed ew2 and got 180 on all 4
i did this wormed up and with WOT all plugs pulled. now what is this 300rpms. it cant hold if there is no sparkplugs to run?

[chedda_j]

ok im confused.
i did a test on my carbed ew2  and got 180 on all 4
i did this wormed up and with WOT all plugs pulled. now what is this 300rpms. it cant hold if there is no sparkplugs to run?

<{POST_SNAPBACK}>

Well then you should be really good then. you might have a bunch of shit on the top of your pistons...i doubt it tho. 300 rpms means turning it over i believe.

[3gencivic]

so even though im over the normal 164 by 16 i should be ok still. its when it gos lower that i should worry?

[chedda_j]

so even though im over the normal 164 by  16  i should be ok still. its when it gos lower that i should worry?

<{POST_SNAPBACK}>

LoL very. You might be just getting lucky with the seal on the rings. They must be seated very good. Lucky you. Less blowby=more compression and horsepower and less oil changes.

[3gencivic]

^^^ its a sedan ew2 too. in a hatch droped it in my first hatch at 210k and now its in this one 4 years later at 220k and going strong