Compression numbers

[Eggdrop]

I just ran a compression test on my motor and this is what i got. 130,125,125,130
Hopefully I did the test right, i had the pedal depressed and I cranked it for 6 cycles. I searched and saw that the numbers should be like 160. Now this motor was rebuilt. Is that the reason my numbers seem so low compared to the ones I ve seen talked about here.

[Id RaThEr DrIfT]

holy shit i dont know if there any difference from an sr or if it does have to do with the rebuilt but i think there pretty low last time i heard i think the lowest was 130 lol mine was pretty bad also 140 145 140 145 but that was i belive with out WOT dont know if it makes a difference but yeah

[keepitmovin]

SR compression should be 160 iirc. The numbers you posted are somewhat balanced, but are kind of low for sr or ka. What motor do you have?

[punxva]

yea they do seem a little low, how many miles are on the engine? if its just rebuilt then the rings arent set all the way yet, so they arent sealing, but thats the only thing that i could think would cause this on a rebuilt engine, but how many miles does it have on it, and what engine is it

[Silverbullet]

What head gasket was put in? If its a taller aftermarket head gasket, then your compression will be slightly lower than OEM spec (150-155)... but 130 i dunno. Atleast its fairly consistant.

[sepulchral]

my first sr'd 240 had numbers like this 135 138 145 140

very bad numbers but the car pulled its ass off, and with the yokohomo (sp?) tuned ecu it could arun high 12s on only 1 bar

[Eggdrop]

i have a SR.its got about 3000 miles on it. i want someone else to do the test just to make sure i didnt fudge it up. it is the first time i ran a compression test

[xxsptcuztomsxx]

hmm....maybe a blown hg between cylinders 2 and 3? My compression was like 120, 105, 105, 125. Turned out i had a blwon head gasket. Take it to a radiator shop and get them to test for exhaust gases in your coolant system.

Also, check for water in your oil and visa versa. Check for water in your catch can as well.

[fliprayzin240sx]

Per FSM...SRs are still within spec at 125 psi. IF this is a KA...your fooked!!!

[thejester03]

Hahaha, 1993 Coupe original KADE, 184k (abused) miles, 155, 155, 155, 160. How do ya like them apples?

[steve shadows]

the numbers the origional poster posted are fine.

Try cranking the engine for 10 cycles this time and try it again, if it hits 145-155 across with less than 5 psi discrepancy between each cylinder your peachy keen.

I think its ok though.

Is there another issue that spurred your need for a comp test? Just curious.

[240-Trevor]

Make sure you remove the fuel pump fuse and start It let It die (all fuel burned) and then remove all the spark plugs, leave the fuel pump fuse out... If you are compression testing with the fuse In you will have unburned fuel entering the cylinders making the test inaccurate. Then proceed with the test with the throttle depressed all the way, and about 6-10 cycles.

I don't know If unburned fuel would get you readings In the 130's but Its worth a try.

[Id RaThEr DrIfT]

ecxacly what he said i did that and i got bacickly 150 all across so yeah that works!

[Wei240]

also read that compression test needs to be done w/ warm engine and good battery (not sure if this will also lead to lower #'s???), well, just another thing to look at...