timing issues
#1
timing issues
ok i broke in my cam with 100lbs springs like the instructions said. and then replaced them with the springs that i'm suppose to run 385lbs. runnin a solid lifter cam all valves set at .026" 54 cc heads, headers, 350 block, edelbrock air gap intake and 670 holley street avenger. i started the motor to set the timing. For some reason the only way to see the timing mark on the balancer is if i set my light to 40 degrees advance at a idle ok i know this is way to high it suppose to be around 12 or so..but if i retard the engine it sounds like crap and i can't keep the idle going. also for some reason i am hear a strange knock sound coming from the tail pipes. Also when i pop the motor from idle or just above idle it will back fire thru the carburetor ( not under load). i check all wires for proper firing order. any suggestions to fix this?
#3
Site Ambassador
What vacuum source is your vac advance on the distributor hooked up to, ported or full manifold? If manifold vacuum, you're advancing your timing a bit at idle and you need to disconnect the hose before setting your base timing. If you have mechanical advance, your issue could be with the weights and/or springs kicking the advance in too soon.
#4
no i didn't stan. and of course i should never assume but i just assumbed that the groove that is on the harmonic balancer was suppose to be tdc i never double checked to make sure that was accurate.
Camaro 69. i didn't have the vacuum hose connected to the distributor it was blocked off. i was not planning on using the vacuum advance anyways due to the fact my motor is in a dirt track race car and will not be driven on the street at all. the weights and springs are the origanal ones that came with the distributor. the distributor is a msd streetfire no ignition box. should i change out the springs and weights??
Camaro 69. i didn't have the vacuum hose connected to the distributor it was blocked off. i was not planning on using the vacuum advance anyways due to the fact my motor is in a dirt track race car and will not be driven on the street at all. the weights and springs are the origanal ones that came with the distributor. the distributor is a msd streetfire no ignition box. should i change out the springs and weights??
#5
Site Ambassador
I wouldn't start messing with that yet. It's possible you may have the wrong harmonic dampener (some have the notch in a different clocked position), or the outer ring may have slid around. Do you know how to find your true #1 TDC using a piston stop?
#6
no i have done with with a screw driver. i stuck in the sparkplug hole when i know i am on the compression stroke turned the motor by hand till i see the screwdriver top and then start to go back to down. the turn the motor back just a little bit where that lull is between it stopping at top and goin back down.
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#9
Site Ambassador
From your first post "if i set my light to 40 degrees advance".... I take it you're using a dial back timing light.
Have you checked with a conventional timing light to make sure the problem isn't with the dial back?
Have you checked with a conventional timing light to make sure the problem isn't with the dial back?