Re: Compression - is it important ?

Posted by Rusty O\'Toole On 2011/2/21 7:31:14

You could probably lose 10% of your compression without a noticeable reduction in performance. I know of cars that were supposed to have 120PSI, that ran satisfactorily with half that. They were rather sluggish and down on mileage but started and ran OK. The difference was not evident until the engine was rebuilt and power restored, then the difference was obvious.

This is especially true of old flathead engines. They can be in an advanced stage of wear without making any fuss about it.