[rwarre]

Have a Lycoming o320 narrow deck 7:1 compression ratio. Called Lycoming who gave me the year the engine was made (1955) and told me this engine could not be up-graded to 8.5:1 pistons. The engine was rebuilt by Stein and everything was new using the old case halves. I have read most all of the threads concerning the upgrade, would like to find out if anyone else has this type of engine. I am not unhappy with the performance I am getting, not as fast as other RV's) but still better than most factory made. ECI Titan cylinders and pistons, 2003 manufacture. Thanks

 

[Bdalporto]

I also have a straight O-320 out of an a PA-23 built around that time. I'm planning to put in 9:1 CR pistons, in fact I already have the pistons. I doubt Lycoming would approve this installation because no one has ever received an STC for it. Not sure if its right or wrong. I guess I'm going to have to research this some more.

Brian

Have a Lycoming o320 narrow deck 7:1 compression ratio. Called Lycoming who gave me the year the engine was made (1955) and told me this engine could not be up-graded to 8.5:1 pistons. The engine was rebuilt by Stein and everything was new using the old case halves. I have read most all of the threads concerning the upgrade, would like to find out if anyone else has this type of engine. I am not unhappy with the performance I am getting, not as fast as other RV's) but still better than most factory made. ECI Titan cylinders and pistons, 2003 manufacture. Thanks

 

[jrs14855]

engine

You need to check with someone like Mahlon. Some of the very early 0 320 narrow decks did not have the cylinder hold down plates. I believe these cylinders may have been more fragile, but I'm not certain of this. The STC conversions require nitride or plated cylinders for the 160 hp conversion. There are lots of homebuilts doing fine with 160 hp plain steel cylinders.