| Jtrux |
03-13-2007 05:39 PM |
Re: Weekend progress...pics soon to come.
Quote:
Originally Posted by Blizz
(Post 2072750)
it idled really rough so we adjusted it and it seemed to run better, ie. it didn't want to die as soon as i put it in gear. it just feels like it's missing and i can almost hear an open vacuum line. so...did i ever mention that i'm a computer guy? forgive my ignorance...but what/where is the dwell? the fuel filter might not be a bad idea either. this thing sat for about a year with the PO and just about a year here also. i've started it about 8 times. i'm constantly being chastised by my brother (gearhead) for not starting it more often.
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I don't know the 100% correct definition but i'll tell you what it basically is. Dwell is the time in which the points are closed allowing current to flow through the coil and build up voltage. On other vehicles i've worked on (Fords, some old tractors, etc.) you adjust the points with feeler guages when the vehicle is off but on chevy's there is a little window on the side of the cap that allows you to place a small screwdriver inside the distibutor while the truck is running and adjust it. On chevy's you adjust how long the points stay closed and on fords you're adjusting how long they stay open but it all works out the same in the end but on chevy's it's easier and more accurate.
That's dwell for you but now i'm gonna explain why it works and why it would cause your truck to run rough.
While the points are closed the current is flowing through the primary (+) post on the on the coil, flowing through the primary windings of wire inside the coil and out the negative post into the distributor housing and it grounds itself out through the closed points. While the current is flowing through the coil, a magnetic field is being created inside the coil ( it's one of the characteristics of electricity, if it passes through a conductor a magnetic field is created ). A certain amount of time is needed to build up the right amount of voltage, not enough time and you don't have a powerful spark (will run rough) and too much time and the coil reaches peak voltage and then the voltage starts to drop off ( again, will run rough). That's why you need to have it adjusted just right. When the points open up alot happens at once. Since the current can no longer move through the points and ground itself out the current stops moving in the coil and the magnetic field drops allowing the current to jump to the center of the coil called the secondary windings. When it does this the voltage multiplys many times into the thousands (25000 -50000 approximately depending on coil) and shoots through the secondary tower (where the spark plug type wire is hooked to that goes the the center of distributor cap) and is sent to the appropriate spark plug.
That's not everything but it's enough, if you have any other questions just ask. |
