My SD died last night.... I guess the timing chain Broke. I was on a trip in NC and it started to make this horrible ticking noise. I was going about 20 MPH and I heard somthing give and it died. I guess I ruined the entire engine. I took a screw driver and touched the chain and it was very loose. Did I destroy the valves? What else? Will a new cylinder head and chain and tensioner fix it? It just turned 253,000