OK I have read allot of posts here. Still not sure of answer. Bought an e34 93 m50 525i. Got it for a good price but not running. CHecked allot of things thinking a dumb sensor, NO. After checking spark and fuel( by lifting injector bar and causing a wonderful explosive fire on the block, put it out quickly no damage). Got that. Did compression check . 125 cylinder toward radiator. zero on 2nd 3rd 4rth, 5 had 50 psi and 6th zero. thought head gasket or ??? so decided to check with ghetto leakdown test by potting air in cylinders and listening for air in usual places. well on my way to getting to the cams and removing leaky valvecover.bingo broken timing chain. engine has cranked over with no odd noises. what would i have to check before just replacing time chain. what could all be damaged? still plan on doing leak down to see if valves are holding but andy other things to be made aware of? Thanks for reading all this. its a nice car great interior and love to get it running sweetly. Ed