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#76177 04/12/2007 4:40 PM | Joined: Jan 2007 Posts: 172 Wrench Fetcher | | Wrench Fetcher Joined: Jan 2007 Posts: 172 | There has been lots of talk here about setting the timing....but I have to ask some really basic questions.
On my '65, I have a line on the (harmonic balancer?) and a bit of metal with a bunch of teeth on it. But no numbers as others have pointed out.
1) Do the teeth on that metal bit represent any kind of measurement, or are they just for reference points?
2) When we say BTDC (before top dead center) is my line supposed to be to the left of those teeth?
3) How far to the left? When I started to check, the line was way out left past the teeth. (This probably due to me replacing the dizzy while on side of highway.)
4) When we say 'advance' the timing, does that mean move the line closer to the center of the teeth?
5) If the line is left of the center line on the teeth...that means that my detonation is happening...after TDC?
Ok, I think I am out of newbie questions for the moment.
1965 Chevy C-30 1-Ton "Work like you don't need the money. Love like you've never been hurt. Dance like nobody's watching." | | |
#76178 04/12/2007 4:53 PM | Joined: Jul 2004 Posts: 5,708 'Bolter | | 'Bolter Joined: Jul 2004 Posts: 5,708 | sablesurfer,
Good questions. The crank pulley rotates clockwise as viewed from the front. As the mark on the pulley approaches the first in the series of lines on the tab...this is the MOST advanced. Usually the LAST line on the tab equals 0° BTDC. 0° before top dead center is TDC!
To speculate, the last line in the direction of rotation is TDC and each line before that usually represents 5°...I think.
Does this make sense!
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#76179 04/13/2007 12:48 AM | Joined: Dec 2006 Posts: 1,464 Shop Shark | | Shop Shark Joined: Dec 2006 Posts: 1,464 | sablesurfer; First off, I looked at your gallary article to determine that we're talking about a 292 - right? When you say "left of the center line" are you talking about as viewed from the front?
"advance" on the timing means the number of degrees before TDC that your ignition "fires". Look closely on that thingy with the teeth on it, one of them should be marked with a "0" - that is TDC. As atomarc says, the crank is rotating clockwise as viewed from the front. The ignition should fire a few degrees BTDC, i.e. "left of the mark" as viewed from the front. I'd start with about 6 degrees BTDC and go from there. I believe each "tooth" and each valley represents 2 degrees. BUT, before you put the light on it, check your point dwell, should be 31-34 degrees (if your don't have a dwell meter, check the gap - should be .019", THEN remove and plug the vacuum line going to the dizzy, now you're ready for the timing light. As has been stated before recently, you can experiment with the amount of advance you finally end up with by listening for a slight pinging under load, then back off the timing (retard it) until the pinging just goes away. | | |
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