Hopelessly Confused Posted June 17, 2007 Share Posted June 17, 2007 Okay, I have a 350 sbc and there is a single black wire coming off the distributor. Im assuming that it is a ground wire but thought I would ask before I wired it wrong. Quote Link to comment Share on other sites More sharing options...
pparaska Posted June 17, 2007 Share Posted June 17, 2007 Where is it connected to? An points type distributor would have that going to the negative side of the ignition coil. An HEI only needs + battery voltage. So knowing what kind of distributor is important. Quote Link to comment Share on other sites More sharing options...
Hopelessly Confused Posted June 17, 2007 Author Share Posted June 17, 2007 The wire is coming out of the bottom of the distributor as far as I can tell. How can you tell what type of distributor it is? Quote Link to comment Share on other sites More sharing options...
lbhsbZ Posted June 17, 2007 Share Posted June 17, 2007 Does it appear to be some type of aftermarket performance distributor or are we talking original GM stuff? GM had 2 types of distributors that are most used on small blocks prior to about '89. Points and HEI. The Points distributor had about a 3 1/2" diameter cap, with 8 terminals for the plug wires and one in the middle for the coil wire. If this is what you have, there should also be a condenser (looks like a little metal barrel with a wire coming out of one end....the condenser is about 1 inch long by 1/2" diameter) screwed down right next to the points...visible after you remove the distributor cap. The one wire coming off the points hooks up to the negative coil terminal. HEI distributors have huge caps...about 7" around, with only 8 terminals on top for the plug wires, and a big squarish thing in the middle of the terminals....this is the coil. There is no external coil on an HEI. On one side of the cap, there is a square plastic protrusion that houses 5 female spade connectors. The 3 closest to the cap are coil, breaker, and ground connections, the two farthest from the cap are for the Tach and key hot. they are labeled if you look at the top of the cover. From what you are describing, you've got a points distributor. Quote Link to comment Share on other sites More sharing options...
Hopelessly Confused Posted June 19, 2007 Author Share Posted June 19, 2007 Thanks for all the input. But now I hooked it all up so the coil has +12 volts and is grounded and the wire that comes from the distributor to the negative side of the coil. But when I crank on the starter it turns over fine and I have fuel but I dont have spark. Is there any easy ways to check the coil/distributor? Quote Link to comment Share on other sites More sharing options...
LeeMS Posted June 19, 2007 Share Posted June 19, 2007 There is no ground for the coil. Ground is provided through the dist. the block and the engine ground strap. The negative side of the coil only go to the dist. Quote Link to comment Share on other sites More sharing options...
pparaska Posted June 19, 2007 Share Posted June 19, 2007 Just a recap on how a points ignition works, etc. Sorry if you knew this: What LeeMS is saying is that the case of the coil is actually insulated from the winding, and it is connected to one end of the secondary winding (the winding that gets routed through the distributor rotor to the plug wires and plugs). The points, when closed, complete the primary winding coil circuit by connecting the (-) negative side of the coil primary winding to ground through the point contacts, the points body, the plate the points are bolted to, the distributor body, the intake manifold and/or engine block, and then the ground strap to the chassis and then to the negative side of the battery. The other side of the coil (+) primary winding is connected to switched positive battery voltage. When the points open, the back emf in the primary winding induces a high voltage in the secondary winding of the coil. The coil body is connected to one side of this winding (which gets grounded to the engine and ultimately connects to the battery and alternator (-) negative connections. The other side of the secondary winding is connected to the center tower receptical on the coil, that has the "rotor" wire connected to it and the center of the distributor cap. From there the rotor takes the spark voltage to another post on the cap and the spark plug wire takes it to the plug center electrode. The casing of the sparkplug is obviously grounded to the cylinder head, which connects electrically to the block and the chassis to be connected ultimately to the battery and alternator (-) terminals. Hope that helps. Anyway, the single wire from the distributor bottom connects to the coil (-) terminal, a switched battery (+) voltage wire connects to the (+) terminal. Don't run a ground wire to anything but the case of the coil and the distributor body, but those things are usually well grounded if an engine-to-chassis ground strap is in place. Quote Link to comment Share on other sites More sharing options...
Hopelessly Confused Posted June 19, 2007 Author Share Posted June 19, 2007 Okay, that would probaly explain why its not working. I'll try firing it up tonight. Thanks for all the help. Quote Link to comment Share on other sites More sharing options...
SilentNight1647 Posted June 19, 2007 Share Posted June 19, 2007 The easiest way to determine what kind of distrubitor you have is to look at the connection, if it is a sockect on the cap it's points, if it's a sockect on the wire it's an HEI, and I do beleive the single black wire goes to the negative side of coil like pparaska said at least that's the way my 240 is wired. Quote Link to comment Share on other sites More sharing options...
Hopelessly Confused Posted June 19, 2007 Author Share Posted June 19, 2007 Okay I hooked up the distributor to the negative side of the coil, so thats the only thing on the negative side, and it still doesnt work, any suggestions? Quote Link to comment Share on other sites More sharing options...
MONGO510 Posted June 19, 2007 Share Posted June 19, 2007 Have you taken a look inside the dist.? Quote Link to comment Share on other sites More sharing options...
Hopelessly Confused Posted June 19, 2007 Author Share Posted June 19, 2007 Yes I have looked im not quite sure what I should be looking for but I did check the continuity of the wire and it was good. Quote Link to comment Share on other sites More sharing options...
Hopelessly Confused Posted June 20, 2007 Author Share Posted June 20, 2007 Well, im probaly the stupidest person alive. I thought I had it in netrual but evidently I didnt becuase the truck ran straight into a concrete wall when it finally fired up. Quote Link to comment Share on other sites More sharing options...
Hopelessly Confused Posted June 20, 2007 Author Share Posted June 20, 2007 Heres some pictures of the damage. What I dont is it should have been in netrual because its free rolling or maybe im missing something. Quote Link to comment Share on other sites More sharing options...
LeeMS Posted June 20, 2007 Share Posted June 20, 2007 Glad you're not hurt! One good lesson learned AWAYS stand on the side of a vehicle when working on a running or possibly running engine. Also good to have a fire extinguisher and a friend standing by, Now about body work...... Quote Link to comment Share on other sites More sharing options...
Hopelessly Confused Posted June 20, 2007 Author Share Posted June 20, 2007 Thanks, I got lucky, could have ran myself over. As far as body work though I might just end up replacing the cab so I can one 74 or older. Netrual is on only gear that you can roll the vechile back and forth, right? Quote Link to comment Share on other sites More sharing options...
pparaska Posted June 20, 2007 Share Posted June 20, 2007 I've had people give me a hard time about wanting to hook up a clutch or neutral safety switch on manual swaps. Your experience is not singular by any stretch of the imagination. I KNOW I'm stupid enough to at some point hit the key when it's not in neutral. Did you ever get it to fire? Quote Link to comment Share on other sites More sharing options...
Hopelessly Confused Posted June 20, 2007 Author Share Posted June 20, 2007 Yeah, it fired up good. Thats how it hit the wall. Umm the problem was that when I turned the key for the starter the relay I had powering the coil lost power. So I hooked up the coil straight to the battery, I thought I had broke something so I didnt take many safety percautions. I had also put way to much gas in the carberautor so when it started the back wheels did a little burnout and then slamed into the wall. Luckily the truck was only about 2 feet away so it didnt have much speed. Quote Link to comment Share on other sites More sharing options...
Teekass Posted June 20, 2007 Share Posted June 20, 2007 Netrual is on only gear that you can roll the vechile back and forth, right? Your TH350 (along with most automatics I think) will roll in gear, although not as freely as it will in neutral. Quote Link to comment Share on other sites More sharing options...
Hopelessly Confused Posted June 21, 2007 Author Share Posted June 21, 2007 Ah, that would explain my confusion, I thought they were more like manuals in that respect. I guess you learn something new all the time. Quote Link to comment Share on other sites More sharing options...
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