73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: the_legend_1981 on March 11, 2009, 05:40:52 pm
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can i play with it and not mess it up? or should i use a light?
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play til your heart's content. You might wanna make a chalk mark or note where your vacuum advance thing is pointing (if equpped). Loosen the hold down bolt and do what Chubby Checker says, "C'mon baby, do the twist!"
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I rarely use a timing light on the older trucks. I turn it til it is sluggish to start, the back it off til it just fires easily. It have rechecked it after doing this, and it puts it about 4 degrees btdc. I have never had a problem doing it this way
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i run her advanced timed (turned distr. counterclockwise) til she detonates and rattles under load, then retard (turn clockwise) a tad at a time til the rattle goes away. Shes usually right on the money then.
When using a light, I too like it advanced a couple few degrees BTDC. I dont care what the specs say, I know when she feels I hit that sweet spot.
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That sums it up for me as well
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With a V8 and an hei vacuum advance distributor set your initial timing at 12° btdc and play with it from there.
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I do just like SgtDel says, crank it up until it rattles slightly under load and then back it off a bit. I keep an offset 2-piece timing wrench in my glovebox to make it easy :)
Related to that, before my cam and heads swap, I could not advance my timing enough to make my truck detonate from too much timing. Even on 87 octane gas, sea level dense air, heat of summer or cold of winter, nothing. I turned it up far enough that it actually slowed down considerably, and it wasn't all that fast before that lol I figure with the big cc chambers of the low-po heads it had on it plus the 60-thou overbore, it just didn't create enough cylinder pressure to make it detonate. Now that I have new cam and heads though (and new HEI), I turned up my timing some after my mechanic did the install and it would ping on 87. I have it now where I have to run 94 octane. Hurts when I fill it up but that's so rare that I don't mind and I want all the power potential I can :)