91' CRX Si D16a6 SOHC nonvtec
145, 140, 145, 150

decent numbers? or not... I also have a stage3 cam w/ 270 duration and im not sure if taht would effect the numbers.

 

The cam shouldn't affect the numbers because you should measure compression at TDC before what would be the power stroke (assuming the engine was running) when all of the valves in that cylinder are shut.

 

Those numbers seem really low to me. I would suggest to do a leak down on the motor and are you sure you put the cam in correctly along with the timing belt? Also is your head milled at all.

 

The numbers seem low to me as well, but as long as they are consistent then you should be okay I believe.

 

Couldn't my cam be the cause of the lower compression #'s?

Stock cams cause valves open and close quicker, so during the stroke the cylinder has more time to compress while the valves are closed

This is a Stage3 w/ 270 duration race camshaft, Would it be why?

Aftermarker cam w/ longer duration keeps the valves open longer so while during the stroke the valves are still open releasing air, thus giving a lower compression number because less air was compacted.


This is an untuned cam w/ stock camgear.

 

those are low numbers...do leak down test

 

almost as low as my sohc accord

 

Typesi2nv is correct. the cam WILL have a impact on compression test results. you guys should search and you will also learn this.

those numbers look perfectly fine for the year/engine.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dc231 &raquo;</TD></TR><TR><TD CLASS="quote">The cam shouldn't affect the numbers because you should measure compression at TDC before what would be the power stroke (assuming the engine was running) when all of the valves in that cylinder are shut.</TD></TR></TABLE>What??Yes it will affect the readings.valves are open longer and will bleed off more pressure at low RPM such as when doing a compression test.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fkned &raquo;</TD></TR><TR><TD CLASS="quote">What??Yes it will affect the readings.valves are open longer and will bleed off more pressure at low RPM such as when doing a compression test. </TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by non-VTEC &raquo;</TD></TR><TR><TD CLASS="quote">Typesi2nv is correct. the cam WILL have a impact on compression test results. you guys should search and you will also learn this.

those numbers look perfectly fine for the year/engine.</TD></TR></TABLE>

thanks see.. I knew i wasnt crazy all along.

naa, I have known about that for a while but too many people were trying to tell me i was crazy and i was wrong.