i am trying to figure out what the normal compression for 99 civic d16s are. can anyone help me out. thanks

 

Compression ratio? Or compression in PSI?

 

Compression check:
Normal: 184 psi.
Minimum: 135 psi.
Max Variation: 28 psi.

Done with wide open throttle

Compression ratio: 9.4:1

This is assuming it's a non-vtec (as you did not specify).

 

my bad guys it a 99 v tec d16 motor. i did it today and it came out 140 all across with close throttle and the engine is warmed up. is that normal or should it be higher?

 

should def be higher. its supposed to be done with open throttle

 

open throttle and all plugs out. and i believe compression tests should be done with a cold engine. but yes 140psi is low.

 

It is above minimum spec. How many kms (or miles i guess if you're american lol) on the engine? If it's got high mileage then i would say that it's normal.

 

sorry, let me correct myself. no 140 is not TOO low, but its definitely on the low end. try doing a wet test by squirting some oil in each cylinder before you run the test and see what your numbers are then.

 

but he needs to do it when the motors cold and with an open throttle those numbers are probably wrong

 

so lets get this straight. i need to make sure the motor is cold and the spark plugs and wires need to be out, and keep the throttle open at all time correct?

what does the wet test do by squirting oil in each cylinder and how much oil should i squirt in it.

plus the motor has 123*** miles on it.

 

Yeah my SOHC is about 180 across the board, 140 seems pretty low. I have 150k miles, what's your mileage?

 

If you squirt a bit of oil in the spark plug holes you create a better seal at the rings. If the compression goes up after you have done a wet check, then you can conclude that the rings or cylinders are worn.

 

some idiots do compression test when the motor is warm and those readings are inaccurate and high. best to do them WOT and when the motor is cold to the touch. you should be seeings some where near 150-180psi.

 

are you guys nuts?? compression should always be checked with the engine as close to operating temperature as possible.

 

hes right, just checked it in mitchell "engine at normal operating temperature, all spark plugs removed, throttle valve open, and full cranking speed, crank at least 6 times"

thanks for the correction

 

the wet test is to show worn rings vs other possibilities..........if there is no change between a wet and dry test then the next step is a compression leakage test(CLT) which will pinpoint possible leakage points(head gasket, intake or exhaust valves, or rings)

 

yea thats what i thought too, so the compression test when the engine is warm. i guess ill do the a wet test also to see if the rings or the walls are warn down.

 

uhhh i don't get where you all get your info. its supposed to be cold. just like when you do a valve lash adjustment....with it warm it is going to yield higher compression numbers from the heat....it's common sense

 

*facepalm* for the majority of people it's common knowledge that the engine needs to be warm. if you searched you'd find numerous explanations of how to check compression. i have yet to find one saying you should do the test cold. ALLDATA also agrees with me.

 

nice find bro. i have one more question. what is ensure is fully charged and that cranking speed is 250 rpm. you know who to read the crank speed?

 

it just means that to do a compression test 100% right the engine needs to be cranking at its normal speed, if you have a weak battery or starter then you wont be cranking at full speed..............you dont need to worry about knowing exactly how many rpms its cranking at, just make sure it sounds like its normal cranking speed.