# sr20det low compression on 3rd cylinder

**URL:** <https://forums.speedlife.net/t/sr20det-low-compression-on-3rd-cylinder/124560>\
**Category:** SON240sx Automotive\
**Created:** [May 17, 2009, 4:33pm UTC](https://forums.speedlife.net/t/sr20det-low-compression-on-3rd-cylinder/124560 "2009-05-17T16:33:53Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![cchabot](https://avatars.discourse-cdn.com/v4/letter/c/5fc32e/32.png) [@cchabot](https://forums.speedlife.net/u/cchabot)\
**Post date:** [May 17, 2009, 4:33pm UTC](https://forums.speedlife.net/t/sr20det-low-compression-on-3rd-cylinder/124560/1 "2009-05-17T16:33:53Z")

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im lookin into buying a 93 240 hatch with an sr20 swap. i performed a compression test and cylinder 1,2, and 4 had readings around 170. but cylinder three was reading only 150. is this a major issue? i have been reading that a compression over 140 is good but a difference of 15 psi between cylinders is bad. hit me back, im looking to purchase soon.

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**Author:** ![sr20](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/sr20/32/5491_2.png) [@sr20](https://forums.speedlife.net/u/sr20)\
**Post date:** [May 22, 2009, 8:51pm UTC](https://forums.speedlife.net/t/sr20det-low-compression-on-3rd-cylinder/124560/2 "2009-05-22T20:51:38Z")

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how long has the motor been sitting?? my old car w/ an sr sat for at least 2 weeks after my accident, when it was time for it to get sold we checked the compression on it and one of the cylinder reads low. we added a little oil on it since it sat for a while and the compression went up. you should try that