Whats good compression on a DC2 ITR

[beeker]

Car done 100,000km

Have a report saying an evenish 130 (with#4 at 127)

Is this good and expected compression ?

[dazznz]

Are you talking psi? Because if so that seems really low to me. My motor used to be over 200

[beeker]

Originally Posted by dazznz

Are you talking psi? Because if so that seems really low to me. My motor used to be over 200

Note sure. Its a german instrument, so maybe its metric

[crx_bob]

If you are reading in PSI then that is low, if not you might need to find a conversion chart.

More imporant is the variation between cylinders, they should be close together on readings which you have, so I would try to find out what form the guage is reading in.

Bit of a Tech Help question really.

[beeker]

Originally Posted by crx_bob

If you are reading in PSI then that is low, if not you might need to find a conversion chart.

More imporant is the variation between cylinders, they should be close together on readings which you have, so I would try to find out what form the guage is reading in.

Does a "motometer" make sense, made in Germany.

[gotvtec]

http://www.onlineconversion.com/pressure.htm
Could be decibar reading
According to that link, 130 decibar is 188 psi which sounds ok, and the readings are close to each other so should be ok. In my Noob opinion anyway

[beeker]

I've just clarified it. Its consistent accross all cyclinders, but his printout uses non orginal printing media, thus the actual PSI/KPA reading is non relavent.

He said it looks normal thou.

[Horny_Devil]

again i have to keep saying this. the reading u get means nothing as its all dependant on how u tested it and the gague etc etc.

cam duration, engine temp, air temp, throttle plate, general condition of the motor, seal of the tester, the gague, all play a part in the reading.

its the difference between the readings that u should worry about. the highest to lowest shouldnt be more than 24psi

they seem fine to me

[dazznz]

Originally Posted by Horny_Devil

again i have to keep saying this. the reading u get means nothing as its all dependant on how u tested it and the gague etc etc.

cam duration, engine temp, air temp, throttle plate, general condition of the motor, seal of the tester, the gague, all play a part in the reading.

its the difference between the readings that u should worry about. the highest to lowest shouldnt be more than 24psi

they seem fine to me

Not wanting to dis your theory, but what if all of your clinders have droped by a similar amount in compression? There may not be a big difference between them, but you would still not have a healthy motor.

[Pommy]

Originally Posted by Horny_Devil

its the difference between the readings that u should worry about. the highest to lowest shouldnt be more than 24psi

they seem fine to me

*EDITED for the sake of humanity, or so it seems*

[Horny_Devil]

if u had used the same gague before and tested it useing the same method then if they had all droped, ud have a problem. if ur using a different gague then how can u be sure its not the gague reading differently? and the compression isnt fine?

normally, ull get 1 maybe 2 cylinders that will drop compression

[2HEKTK]

Originally Posted by Pommy

"Ah, my motor is running 3 psi in all cylinders, but thats ok according to the devil horn guy on teh internetz as there all reading the same, SWEET!"

Its getting a bit old now dude.

Jase is right in the fact really what you need to worry about is the difference across the cylinders. If you throw common sense in the mix im sure you can form a decent conclusion.

[Bigelboe]

Originally Posted by Horny_Devil

if u had used the same gague before and tested it useing the same method then if they had all droped, ud have a problem. if ur using a different gague then how can u be sure its not the gague reading differently? and the compression isnt fine?

normally, ull get 1 maybe 2 cylinders that will drop compression

The absolute value from a compression test can be quite helpful in determining compression ring wear (which is often fairly even), especially when combined with squirting a wee bit of oil in the cyl and trying again.

[tysonzane]

It would be almost impossible for all the cylinders to drop the exact compresion across the board.

As well as including what horny said all gauges and measuring devices in the world measure differently even from the same brand. So X car might get 180 from your cousins gauge and 200 from joe machanic. Its just like bathroom scales - you may wiegh 2 kg more on someone elses.

[FLYRYD]

the way i have learned it and read in books many many times over and over again.

it is:
the most important thing is that the cylinders are similar in compression, the cylinders should not be more than 10% difference between the highest and lowest reading.