Can I do a compression test by turning the engine by hand?

[Notchbackdrew]

Simple enough question...I just want to turn the engine using the crank bolt. Is this possible or are the revolutions to slow/sporadic? Reason I ask is I have the headers off on one side and the tranny out... I couldnt get to one cylinder earlier because the header runner was in the way. I was curious if I could do a compression test by spinning the engine by hand.

Second question, earlier when I did a compression test I got about 128- 140 in all cylinders besides number 6 (its the cylinder I couldnt get to). The car hadnt been started in 3 days when running the test nor did I open the throttle plate. Is it reccomended I do this test again after warming up the engine, then opening up the throttle plate?

Please let me know.

 

[HISSIN50]

Your arms will probably fall off before you get anywhere doing this manually.

The main thing to look for is consistancy per testing session. As you noted, differences in methodology can yield different results. A hot motor is pretty important for getting somewhat accurate numbers, and propping the Throttle open helps, as does pulling all plugs and putting a charger on the battery.

Good luck.

 

[Notchbackdrew]

well I figure If I used a breaker bar?? no?

 

[CRASH7772]

Your engine needs to be warm...just unhook your coil wire from coil and cap and bump your ignition and make sure throttle is open when doing so. It would take a hour to do it your way.

 

[green]

nope

 

[troyGT03]

no no no