4d56 compression test wet and dry results

[wildplumdx]

so this afternoon i did a dry compression test and \got these results

dry test........1 squirt..........wet test 2 squirts of oil from can
1. 440..........480..............520
2. 440............................. 500
3. 430.............................485
4. 455.............................500


ok so at first i thought i'd add one squirt of oil to seal the rings if the case was bad rings etc but then i decided to do 2 squirts of oil . anyway my theory is it seems 1 squirt bought the compression up 40psi on cylinder 1 as the more oil you squirt in there the less volume you have in the cylinder which in turn would raise the psi correct ? so even tho my psi has risen it has done so in 40psi per squirt so this doesn't necessarily mean my rings are bad ? just means adding oil has risen the psi due to taking up room ? so how do you know if you have bad rings ?

[Big]

low compression.. generally means shagged rings as air is getting past the rings.. someone else might chime in also..but could also mean burnt valves or bent valves as they are not seating properly..Im no mech but im sure something like that..lol

[mud_slinger]

if ya rings are rooted ya compression be low and it would blow lots of blue smoke going by ya dry results compression doesnt seem that low. what is it spose to be factory?

[wildplumdx]

wiki says 384 psi or something around there but i goggled it and someone else on a forum said 440 psi which is what im getting so sounds like i'm bang on

[KloneKilla]

You may not get any smoke at all if it is a turbo. My 4d56 had major sections of bore stripped out as it had been overheated at 382000kms, but she still ran sweet for another 30000km's. the pressure in the cylinders may be enough to keep the oil in the sump. Although it did pump a fair bit of oil out the breather most of the time because the crankcase was presurerising, which meant the oil wouldnt drain from the tappet cover. and after running it down a stepish hill and having it start running on its own oil, I decided to take the breather off and put it into a catch bottle so all i had to do was every 60-80kms stop and pour the oil back in my engine. Mint!

My bores were destroyed when I stripped it, but to be honest if I didn't already know better I would never have known the difference.