March 17, 20205 yr comment_594581 Are those Celsius or Farenheit? Link to comment https://www.classiczcars.com/forums/topic/63677-ignition-timing-mechanical-advance/?&page=6#findComment-594581 Share on other sites More sharing options...
March 17, 20205 yr comment_594588 Kelvin. Link to comment https://www.classiczcars.com/forums/topic/63677-ignition-timing-mechanical-advance/?&page=6#findComment-594588 Share on other sites More sharing options...
March 17, 20205 yr comment_594589 I love Kelvin and Hobbes. Great cartoon. Link to comment https://www.classiczcars.com/forums/topic/63677-ignition-timing-mechanical-advance/?&page=6#findComment-594589 Share on other sites More sharing options...
March 17, 20205 yr comment_594590 I love their social contract work. Link to comment https://www.classiczcars.com/forums/topic/63677-ignition-timing-mechanical-advance/?&page=6#findComment-594590 Share on other sites More sharing options...
April 2, 20204 yr comment_596173 So I've been browsing around the internet watching car videos and came across this guy who has a channel where he finds old cars and builds engines and stuff, and he built one then took it to the dyno for tuning. A Chevy 307. Guess what "best" timing was? Weird. It's at 31:30  Link to comment https://www.classiczcars.com/forums/topic/63677-ignition-timing-mechanical-advance/?&page=6#findComment-596173 Share on other sites More sharing options...
April 6, 20204 yr Author comment_596478 Thanks for that. So I'm assuming that 34 degrees was total timing? But on the dyno at WOT, that would be all mechanical, right? No vacuum. And our engines top out at just over half that for the "base" mechanical. Sounds low. Link to comment https://www.classiczcars.com/forums/topic/63677-ignition-timing-mechanical-advance/?&page=6#findComment-596478 Share on other sites More sharing options...
April 6, 20204 yr Author comment_596479 And on a related note, I've whipped up a little electronic gizmo prototype that applies the mechanical advance in an electronic manner. Reads an input pulse train and effectively outputs a pulse train advanced with respect to the input. The curve looks like the stock curve with a couple adjustments to the numbers to make the math work out easier. 10 degrees advance up to about 1200 RPM Then 1.3ms of delay from 1200 up to 2500 RPM (which mimics the advance slope of the stock curve) And then caps off at 19.5 degrees above 2500 RPM Not sure there's any real value in what I did, but it was an attention diverting academic exercise. I think just that is worth something right now. Link to comment https://www.classiczcars.com/forums/topic/63677-ignition-timing-mechanical-advance/?&page=6#findComment-596479 Share on other sites More sharing options...
April 6, 20204 yr comment_596494 10 hours ago, Captain Obvious said: And on a related note, I've whipped up a little electronic gizmo prototype that applies the mechanical advance in an electronic manner. Reads an input pulse train and effectively outputs a pulse train advanced with respect to the input. The curve looks like the stock curve with a couple adjustments to the numbers to make the math work out easier. 10 degrees advance up to about 1200 RPM Then 1.3ms of delay from 1200 up to 2500 RPM (which mimics the advance slope of the stock curve) And then caps off at 19.5 degrees above 2500 RPM Not sure there's any real value in what I did, but it was an attention diverting academic exercise. I think just that is worth something right now. WOW VERY COOL BRUCE!!!!!! Link to comment https://www.classiczcars.com/forums/topic/63677-ignition-timing-mechanical-advance/?&page=6#findComment-596494 Share on other sites More sharing options...
April 6, 20204 yr Author comment_596507 Haha!! Yeah, if I put in some provision for vacuum advance, I've re-invented the electronic ignition controller for the n+1000th time!!  Completely remove or lock down the mechanical and vacuum advance mechanisms in the distributor and do it with a little module instead. I'll let you know when I've reached the point where I'm willing to put this thing on my car and take it for a drive. Haha! Link to comment https://www.classiczcars.com/forums/topic/63677-ignition-timing-mechanical-advance/?&page=6#findComment-596507 Share on other sites More sharing options...
April 6, 20204 yr comment_596521 I like it. What would be the trigger and how often does it need a trigger? Link to comment https://www.classiczcars.com/forums/topic/63677-ignition-timing-mechanical-advance/?&page=6#findComment-596521 Share on other sites More sharing options...
April 7, 20204 yr Author comment_596558 The design concept is three pulses per crank revolution. Right now it's just using a signal generator on the bench for proof of concept, but if I get energetic, I'll put a variable reluctor front end on it and connect it up the pickup coil on a distributor. In theory, it should work with points. All the math is set up for six cylinders and three pulses per crank revolution. I can get those pulses from either points, or the VR pickup in the later distributors.    In theory.  Haha!! Link to comment https://www.classiczcars.com/forums/topic/63677-ignition-timing-mechanical-advance/?&page=6#findComment-596558 Share on other sites More sharing options...
April 17, 20204 yr Author comment_597316 So I did some reverse engineering of the stock ignition module and patched my contraption into the middle of the box, essentially using the stock module as my VR front end. Then I spun up a distributor on the bench with a variable speed DC motor. And it all seemed to work as intended!   Hey... I got the time, right? It's not like I can drive my car! Link to comment https://www.classiczcars.com/forums/topic/63677-ignition-timing-mechanical-advance/?&page=6#findComment-597316 Share on other sites More sharing options...
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