bad compression on ka

[j3w1z]

i just did a compression test on my DOHC KA and my number were pretty bad..

first try1 - 1552- 1103- 1304- 155

when i put a bit of oil inthey all went up by 20-30 psi

just wondering why 2 and 3 are so low compared to 1 and 4.. is it bad head gasket or leaks?should i fully rebuild this engine or just rebuild the top only? please give me feek back guys.. thanks

[240sxmech]

Answer this question and you will know what you have to do. What does the oil do when you put it in a cylinder?

[Shift_Kouki]

If oil brings them up, you have ruled out head gasket issues. Although them being adjacent to each other (2 & 3) would point to a head gasket, the effect of the oil tells us that's not the case.

This points to your rings going bad. But I forget what the stock tolerances are in terms of PSI.

[j3w1z]

151 is the minimum and 179 is the stardard psi on the motor..

im guessing that 2 and 3 are caused by bad head gasket

[TheOne]

miles on engine? has it been overheated before?

more than likely its piston rings, a leakdown test will give ya more info though.

[j3w1z]

almost 200kms.. the car was overheating few weeks ago.. after i changed the water pump.. i didn't bleed it properly.. but now its not overheating.

[240sxmech]

Do a leak down if it checks out that the head gasket is good then you need a rebuild cause your rings are going out. Let us know what your leak down shows

[240ka24]

your compression is bad enough to justify a ring change. I guess while your changing your rings you can find out whats really wrong with the 2cyl's.

[j3w1z]

so would changing the head gasket and rings bring up my compression to the standard psi level? sorry, this noob is still learning

[240sxmech]

yes after you get your head resurvaced and i would recomend a valve job to be on the safe side

[j3w1z]

oh okay, thanks... before i start anything, im going to do a leak down test