i have been fighting problems with my 524 w/ a broken key @ crank gear, after fixing problem i went to the track and had major timming issues shooting fire thru exhuast and carb. First, i thought i had broken another key, but after teardown revealed the timing chain and key were intact. Assuming i had probley bent some valves when the key had originally broke i began a second teardown, removing the pass side head showed no bent valves no contact of any kind. At this point i'm baffled.... Since i put a Summit Billet Roller chain in when i had fixed the broken key i called summit to inquire what could be the problem with the timing. The tech person advised me that i had installed the Dizzy wrong???????..i had installed the Dizzy the same way i had always instsalled it with No. 1 [email protected] stroke rotor facing 1 on the cap. when i had re-installed the cam after the first tear down i lined up the 0 mark on the crank gear @ 12:00 and the dot on the cam gear @ 6:00, installing the cam "straight up" at this point No. 1 cylinder was @ TDC on compression stroke and i dropped in the dizzy. According to the tech person i was 180 off. he then advised me to turn the motor over (while i had the head off, watching the lifter movement) until i saw the intake lifter moving up and then all the way down which brought the No. 1 up to TDC again. At this point the piston is @TDC and the intake valve has just closed (not quite on the full base circle of the cam) and here is where he said to install the dizzy. i re-installed the dizzy and when i get the new head gasket tuesday i will see if the motor runs properly. At this point i really have no explination of why the cars timming is being such a problem and am willing to try it this way. the tech guy said that the timing mark on the cam gear should be at 12:00 and the timing mark on the crank gear should also be at 12:00 when the dist is installed. My question--- is this all in the timing chain assy i got from summit. the timing chain i had in there before was not set up like this and i wonder if the summit billit chain is different from all the other chains out there? has anybody else run into this before?