Re: identifying timing marks - photo
hello,
generally, the crank's timing comes up on the marker. that is clockwise revolutions. harmonic balancer has a machined cut across it to ID firing mark. i assume that is a gm engine? generally, those timing marks are 2-degrees apart. there usually is a TDC mark.
if it was mine and i was in doubt. i would first dry time the engine, up on cyl #1 top of compression plug out to id the position. a plug in #1 plug wire and it grounded. with distr then loose at the hold down... ignition ON, rotate distr a bit L and R 1/2 - 3/4" back n forth until plug fires... "click, click, click!" this puts distr firing #1 at TDC and is close. tightend distr but loose so u still can move with a nudge if need be. this dry postion should start engine fine. then if vac advance, remove, plug hose and use light to set at 8 or 6 degrees, etc.
in any event, ur engine should have good throttle respons at the 2nd in mark. this is firing about 6-8 degrees BTDC. u can tweak in a bit more advance once it is stabilized and u confirm running smooth.
if it was mine, i would prefer as much advance as i could get given that it cranks smooth and does not hang up when cranking to start it, and it ran cool and no detonation. the GM 5.7 typically likes about 32-34 degrees total at full advance... given all else is in good service.
this should get u started until u can get more specific on the specs on the timing marks.
however, before all that, if i put a timing light on it and it was around ur B mark and it started good, ran good, etc. i would leave it alone for now, unless i had a problem i was diagnosing...
looks like some rust has creeped in.
good luck,
regards
lakester
