Wondering if the 4.0 ohc is an interferance free design ie: if u snap the timing chain do u mash valves with pistons????

Also if anyone could tell me is the timing mark the little metal arrow that hangs out over the crank pulley??? If it is i cant get the timing set that far round the dizzy wont turn that far.... & when its anywhere near the mark it idles fine but put the foot in it and it goes like a bloody ride on lawnmower......

Ideas???

yep,,if anything in that area snaps mashed engine parts will follow,,,as for the timing,,are you putting it into diagnostics mode ?

yeah im putting a clip from the top left to bottom left pins and the revs jump to around 12-1500 revs.