hi all the story is my mate done a compression pressure test on my engine and 3 of the cylinders are 90psi and the over cylinder is only 80psi now we did the test when the engine was cold some one did say to do the test when the engine is hot it has got low compression mahle pistons and rings but he said 90psi is far too low so could mean my pistons rings are fooked and i could be looking at a bottom end rebuild. i can not see how it may need a bottom end rebuid as it has had a fall rebuild not so long a go .here is the engine spec any help would be good