# KA24DE internals **URL:** \ **Category:** SON240sx Automotive\ **Created:** [May 10, 2010, 9:42am UTC](https://forums.speedlife.net/t/ka24de-internals/154775 "2010-05-10T09:42:03Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![shane-s13](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/shane-s13/32/5761_2.png) [@shane-s13](https://forums.speedlife.net/u/shane-s13)\ **Post date:** [May 10, 2010, 9:42am UTC](https://forums.speedlife.net/t/ka24de-internals/154775/1 "2010-05-10T09:42:03Z")
i read in a forum the other day that said if you put SOHC pistons in a DOHC engine it will up the compression from 9.5:1 to 11.0:1 im just looking to find out if it is what it says it is nad what would have to be done or if its nonsence and all that would happen is you get a blown engine out of the deal. thanks -Shane ---
**Author:** ![R33](https://avatars.discourse-cdn.com/v4/letter/r/5f8ce5/32.png) [@R33](https://forums.speedlife.net/u/R33)\ **Post date:** [May 10, 2010, 10:16am UTC](https://forums.speedlife.net/t/ka24de-internals/154775/2 "2010-05-10T10:16:47Z")
yeah only a few 89 240 had them… ---
**Author:** ![BoOsT-HuNgRy](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/boost-hungry/32/5721_2.png) [@BoOsT-HuNgRy](https://forums.speedlife.net/u/BoOsT-HuNgRy)\ **Post date:** [May 10, 2010, 10:18am UTC](https://forums.speedlife.net/t/ka24de-internals/154775/3 "2010-05-10T10:18:01Z")
what forum did you see this on. has me curious as well ---
**Author:** ![shane-s13](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/shane-s13/32/5761_2.png) [@shane-s13](https://forums.speedlife.net/u/shane-s13)\ **Post date:** [May 10, 2010, 11:02am UTC](https://forums.speedlife.net/t/ka24de-internals/154775/4 "2010-05-10T11:02:03Z")
i think it was the NICO club ---
**Author:** ![shane-s13](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/shane-s13/32/5761_2.png) [@shane-s13](https://forums.speedlife.net/u/shane-s13)\ **Post date:** [May 11, 2010, 12:00pm UTC](https://forums.speedlife.net/t/ka24de-internals/154775/5 "2010-05-11T12:00:29Z")
i found the forum its on freshalloy. com here it is [http://www.freshalloy.com/forums/showthread.php?t=50634](http://www.freshalloy.com/forums/showthread.php?t=50634) ---
**Author:** ![d240](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/d240/32/5779_2.png) [@d240](https://forums.speedlife.net/u/d240)\ **Post date:** [May 11, 2010, 12:19pm UTC](https://forums.speedlife.net/t/ka24de-internals/154775/6 "2010-05-11T12:19:52Z")
If you can find an 89 240sx that DOES NOT HAVE a temp sensor in the air-box that is the motor you are looking for-all motors WITH the temp sensor have reduced compression ratio as per factory change-I had a brand new 240 in 89 first run in Ontario and it did not have the temp sensor in the air-box ---
**Author:** ![Elroy](https://avatars.discourse-cdn.com/v4/letter/e/5e9695/32.png) [@Elroy](https://forums.speedlife.net/u/Elroy)\ **Post date:** [May 13, 2010, 8:14am UTC](https://forums.speedlife.net/t/ka24de-internals/154775/7 "2010-05-13T08:14:33Z")
fist 6 months of 89 had the flat top pistons (9:1 i think) supposedly give around 11.7:1 compression with a dohc head after that they had a slight dish (8.6:1 i think) which was supposed to give something around 11:1 with a dohc head there seems like there is going to be a slightly clearance issue with the flat tops, but nothing that can’t be easily fixed with removing a little material ---
**Author:** ![IRo](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/iro/32/5564_2.png) [@IRo](https://forums.speedlife.net/u/IRo)\ **Post date:** [May 15, 2010, 11:57am UTC](https://forums.speedlife.net/t/ka24de-internals/154775/8 "2010-05-15T11:57:33Z")
Now i heard there is a reason they stoped the flat head psitons its was because it was more prone to brake piston rings, or ring lands… Does any one know if that is true? ---
**Author:** ![Elroy](https://avatars.discourse-cdn.com/v4/letter/e/5e9695/32.png) [@Elroy](https://forums.speedlife.net/u/Elroy)\ **Post date:** [May 16, 2010, 6:46pm UTC](https://forums.speedlife.net/t/ka24de-internals/154775/9 "2010-05-16T18:46:38Z")
never heard that. I think service manual states it was done (along with a couple other things) to “improve driveablility”