lowering compression and boring

[kdogg85]

A guy I work with has an 03 with 340k on it, egr went and hydro'd the engine. #5, 1, and 2 cylinders have broken rings in them. Well he has been working a ton of overtime and saving up money, because he wants a compound outfit. Well what better time than, when the engine is out for a full rebuild than to do it.

Anywho, I have seen some talk about lowering the compresion to around 15:1 or so, is the same principle at play as to lowering it on a forced induction gas engine? I brought this up to him and we looked around but haven't had any real details on why this is being done.

This is just about going to be a full restoration on the truck, as he loves it and doesn't want a new one. All suspension, drivetrain, and engine tranny are being gone though, as well as body and a freshening up of the interior. It was bought brand new and it has been maintained with only a couple sensors going bad. Can't gripe too much about that.