beermanpete Posted March 9, 2012 Share #361 Posted March 9, 2012 Not sure how I would do that? I have checked that my coil is getting 13+ volts, and I have tried two different coils. I guess I could wire in a voltmeter to the coil while I am driving. Not sure how I would measure spark intensity thoughAs far as attachments to the coil, I do not have any capacitors attached to my coil or dizzy at all. I am using a Pertronix flamethrower right now. And I am bypassing my ballast resistor.Typically the ignition voltage is measured with an oscilloscope and an inductive probe. This is one of the capabilities of the engine analyzer that was common in repair shops years ago. I don't know if they are common these days. You will need to ask about this at your local mechanic to see if anyone still has one.The Pertronix Flame-Thower coil is advertised to put out 40kV so it should be enough. Link to comment Share on other sites More sharing options...
Zedyone_kenobi Posted March 9, 2012 Author Share #362 Posted March 9, 2012 Okay, I have checked the electrical schematic, how would one go about finding where the ignition is grounded? The coil gets its power from the tach, which gets power from the ignition switch. A weak spark could cause my issue, just need to check every ground in the ignition circuit. This is refreshing,as this is something new!!! Link to comment Share on other sites More sharing options...
240260280z Posted March 9, 2012 Share #363 Posted March 9, 2012 (edited) For reference here is a tool for measuring coil energy/voltage on an EFI Z 18mm gap Edited March 9, 2012 by Blue Link to comment Share on other sites More sharing options...
beermanpete Posted March 9, 2012 Share #364 Posted March 9, 2012 (edited) Okay, I have checked the electrical schematic, how would one go about finding where the ignition is grounded? The coil gets its power from the tach, which gets power from the ignition switch. A weak spark could cause my issue, just need to check every ground in the ignition circuit. This is refreshing,as this is something new!!!The ignition is grounded through the distributor to the engine block. Edited March 9, 2012 by beermanpete Link to comment Share on other sites More sharing options...
Zedyone_kenobi Posted March 9, 2012 Author Share #365 Posted March 9, 2012 Okay, I will ensure everything is cleaned and making good contact, but I am sure it is. The little flexible fabric looking wrapped wire in the distributor that goes from the housing to the pertronix plate may be dirty. I will also check to see if my coil is getting enough voltage as I drive it. More wires coming out of the hood! going to look like an over instrumented test mule before I am done! Link to comment Share on other sites More sharing options...
Captain Obvious Posted March 10, 2012 Share #366 Posted March 10, 2012 So today's question is are you truly lean or are you simply getting a lean indication on the wideband because of a misfire? You ought to be able to test this by dialing in a turn or two of fuel on your nozzles. Assuming the carbs are working properly (ZT says so), if you take them two turns down from where they are now, you ought to be running pretty rich, right?Maybe try that and see what your wideband says?I still suggest you try an old school OEM non-Pertronix distributor. Something with...... ewwwww.... points? I know they're old, ugly, and unreliable, but the fewer variables, the better. Link to comment Share on other sites More sharing options...
madkaw Posted March 10, 2012 Share #367 Posted March 10, 2012 I'm with you to a point cpt. Obvious. Not sure if a nozzle adjustment does much at 4500 even though at cruise. If the floats are a smidge low( I know. I know, here he goes again with the damn floats), there is no fuel to siphon at this point. The neddles are barely off their seat, so the fuel level has to be there-or am I misunderstanding how these carbs work. Link to comment Share on other sites More sharing options...
Zedyone_kenobi Posted March 10, 2012 Author Share #368 Posted March 10, 2012 (edited) I asked Z therapy about the floats and Steve said they were spot on. Also bad floats would also show up at WOT, not just part throttle. I spent the night cleaning connections and hooking up a vacuum gage inline with my manifold. I had to run a line all the way into the cabin from under the hood, but that should suffice. My wide band responds to changes in the idle mixture screw immediately. I was running about 11:1 when I sent them off, and Steve said that his car would stumble badly off throttle and would lean out terribly the way I had them set (2.5 turns from the top). He said he went to a hair over three turns out and he drove his car for 100 miles just like that with no issues at all. I did not touch the carbs when I bolted them up. I went from running 11:1 at idle when I sent them off to 10:1 at idle due the extra turn or so out. Problem is exactly the same. OR at least similar enough I cannot tell the difference. The thing is if I run it 5 turns out, the engine will not run it dies. I would be willing to try a points type distributor if I had one Captian. I would be willing to buy a Mallory Unilite at this point as well. But I do not think it will make a bit of difference accept to lighten my wallet further. Although I do plan on running a Mallory for this engine build I have planned...Hummmmmm Edited March 10, 2012 by Zedyone_kenobi Link to comment Share on other sites More sharing options...
beermanpete Posted March 10, 2012 Share #369 Posted March 10, 2012 Your data from a month or so ago indicates a lean part-throttle condition. Why not try to richen the mixture at part-throttle while leaving the idle as it is. Add some mass to the vacuum pistons. This will richen the mixture at part without affecting the idle. Simply lay some wire solder or other weight to the top of the vacuum pistons (equal amounts for each carb). It is an easy test to see what affect it has to the air/fuel mixture and the miss-fire. If it does not help take it out and go on. If it does help it will give you a direction to go in. Link to comment Share on other sites More sharing options...
Captain Obvious Posted March 10, 2012 Share #370 Posted March 10, 2012 Not sure if a nozzle adjustment does much at 4500 even though at cruise.madkaw, A nozzle adjustment will make a difference everywhere. You can't confine a nozzle adjustment to idle only. That, IMHO, is the biggest drawback of the round tops. If you make a nozzle change it will affect the entire operating range.beerman, that's an clever idea. It would have a small effect on idle, but the effect at higher flow rates would be much more dramatic.Points! Points! Points! Points! Link to comment Share on other sites More sharing options...
LeonV Posted March 10, 2012 Share #371 Posted March 10, 2012 madkaw, A nozzle adjustment will make a difference everywhere. You can't confine a nozzle adjustment to idle only. That, IMHO, is the biggest drawback of the round tops. If you make a nozzle change it will affect the entire operating range.Spot on! You'd have to try different needle profiles in order to tailor the carb to a certain engine. This is when you realize that triples are more user friendly in this regard. Take old jets out, put new jets in. Drive. Repeat. Idle, accel, and main circuits can be tuned separately. Time for triples! Link to comment Share on other sites More sharing options...
Captain Obvious Posted March 10, 2012 Share #372 Posted March 10, 2012 Another option to be able to separate idle from the rest of operation...Flat tops!(Haha! Someone has got to come up with a "poking the hornets nest" smiley.) :bandit: Link to comment Share on other sites More sharing options...
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