I have read a lot and did several searches on my particular issue and if I missed it my apologies. I have a friend that purchased an engine,4.0 SOHC, from a salvage yard. Well the choice was made to use the harmonic balancer that came on the engine. Well on down the road it works loose and starts self destructing. As this is going on it's trashing the gear for the jack shaft chain so it free wheels and the bottom and top end are now in separate zip codes.. Ok so here is knowledge I seek...Can I use the cam alignment tool on the back of the right head camshaft and time the entire top end with it? Since that gives me a definite known position within the mechanism and the top end wasnt diturbed? Also I don't understand that the crankshaft can be rotated freely with zero contact with valves and the camshafts rotate freely without any hesitation,,, Where are the bent valves? With this being a interference engine why would contact not be felt during rotation. I have done a leak down but (correct me if I am wrong) it seems the duration on the camshafts are so long you really can't tell when both valves should be closed.
Whew! Sorry the long drawn out story
And Thanks in advance to those who have the knowledge!
Dave