problems

Hi there I have a gen 7 celica on a 52 plate (uk) I bought the car no realising the engine was pooped, the piston rings had gone. But about 60 miles before having the engine replaced it started to idle really rough and very low (when warm), I just thought it was a one off and kind of ignored it...

Okay so I was racing a douche in a bmw and bent my valves so I got a rebuild on my head. After putting the head back together and driving gentle for about 250 miles I noticed at 6k rpm my lift wouldn't engage and the car would strain. I cant figure it out its pissing me off. Put new oil and...