m-mman Posted March 21, 2019 Share Posted March 21, 2019 (edited) Points and condenser ignition systems. Single point systems have a single condenser, however what I am seeing is that dual point systems also use a single condenser. . . . ? I know there are two types of dual point set ups. High performance where the dual points fire a single coil and spark plug. In this situation I guess a single condenser would be appropriate. Another system is on more ancient cars where there are two point sets and each fires half the cylinders. I have a 1929 Cadillac (V-8) where each point set fires just 4 cylinders through a single coil. I also have a 1926 Lincoln (V-8) with each point set firing 4 cylinders BUT it also has two coils. Each of these set ups seems to use just a single condenser. Considering the work that two points are doing (especially with two coils) shouldn't there be two condensers? Would a dual point (dual coil?) system need a 'larger' (single) condenser? Edited March 21, 2019 by m-mman (see edit history) Link to comment Share on other sites More sharing options...
Bloo Posted March 21, 2019 Share Posted March 21, 2019 25 minutes ago, m-mman said: I have a 1929 Cadillac (V-8) where each point set fires just 4 cylinders through a single coil. I also have a 1926 Lincoln (V-8) with each point set firing 4 cylinders BUT it also has two coils. I must be missing something. On the Cadillac what fires the other 4 cylinders? On the Lincoln, if there are 2 sets of points, and 2 coils, a single condenser would need to be in parallel with the points. How can it be in parallel with both sets of points? Both coils would fire at once. There are 2 setups I am familiar with. On one of them, there are 2 sets of points, 2 coils, 2 condensers, and it is essentially 2 separate ignition systems. one set of points fires every other cylinder. In this way, coil charging time is doubled. On the other type, the type popular in the musclecar era for v8 engines, one set of points does the opening, the other set does the closing. There is one condenser, and one coil. This is essentially the same as a single point system, but allows more charging time for the coil (but probably not double). If the size of the condenser (in microfarads) is wrong, metal will transfer from one point to another leaving a "mountain". Which point the mountain is on tells you whether the condenser should be bigger or smaller. 1 Link to comment Share on other sites More sharing options...
Matt Harwood Posted March 21, 2019 Share Posted March 21, 2019 The '29 Cadillac uses dual points and a four-lobe cam in the distributor (instead of eight) with one coil and one condenser. Either set of points can fire the coil since they're sitting on the same breaker plate and there is only one condenser required since it's still doing 8 cylinders' worth of work. Each set of points fires every other cylinder. The theory was that the points would last longer by firing half as often. I've found that with a good condenser the points will last almost indefinitely in my '29 (good thing because the points are rare and expensive). You don't necessarily need two condensers for two sets of points--the condenser's job is to only dampen the spark that tends to form between the points as they snap open. That spark causes the material transfer between the points and the pitting that ruins points. In theory, the condenser is just a capacitor with a low enough resistance that the current that would be required to jump that gap is diverted into the capacitor. That's why getting one with a correct rating is so important. Two isn't mandatory if one is doing the job adequately. My '35 Lincoln essentially has two separate ignition systems running a single distributor. Two coils, two sets of points, two capacitors, two breaker plates isolated from one another, and one distributor with one rotor firing twelve leads. As long as the capacitor can absorb and discharge the energy in the point gap, it's fine. One, two, one big one, whatever, it doesn't really matter as long as the energy is absorbed before it can make the jump between the points. The capacitor does not play a role in triggering the coil or the spark. The ignition would probably fire without a condenser (for a while, anyway) since it's the points that is causing the magnetic field in the coil to collapse to generate the actual spark. Condensers are just there to make it consistent and reliable, and to increase point life. 4 Link to comment Share on other sites More sharing options...
Frank DuVal Posted March 21, 2019 Share Posted March 21, 2019 So the points are in series? With the condenser across the ends of the series? Link to comment Share on other sites More sharing options...
maok Posted March 21, 2019 Share Posted March 21, 2019 Just to add to Matt's detailed description, its the back EMF 'voltage' from the secondary side of the coil that condensor is used to protect the points. Link to comment Share on other sites More sharing options...
Spinneyhill Posted March 22, 2019 Share Posted March 22, 2019 2 hours ago, Frank DuVal said: So the points are in series? With the condenser across the ends of the series? No, parallel. If either set close, the circuit is made. Link to comment Share on other sites More sharing options...
FLYER15015 Posted March 22, 2019 Share Posted March 22, 2019 Yes, and since electricity travels at the speed of light the condenser has plenty of time to load and unload in either system. Question, If the speed of light is 186.000 miles per second, what's the speed of dark? Shall we move on to the "string" theory, Sheldon ? Link to comment Share on other sites More sharing options...
Matt Harwood Posted March 22, 2019 Share Posted March 22, 2019 7 minutes ago, FLYER15015 said: Yes, and since electricity travels at the speed of light the condenser has plenty of time to load and unload in either system. Question, If the speed of light is 186.000 miles per second, what's the speed of dark? Shall we move on to the "string" theory, Sheldon ? And at the speed of light, what happens when you turn on your headlights? Link to comment Share on other sites More sharing options...
FLYER15015 Posted March 22, 2019 Share Posted March 22, 2019 1 minute ago, Matt Harwood said: And at the speed of light, what happens when you turn on your headlights? OR when you turn them off, where does the light go ? Link to comment Share on other sites More sharing options...
Frank DuVal Posted March 22, 2019 Share Posted March 22, 2019 (edited) 3 hours ago, Spinneyhill said: No, parallel. If either set close, the circuit is made. But it is the opening of the points that fires the coil. This is a four lobe cam two points system, that needs to fire 8 times in sequence, from what I read above. If the points are in parallel, it would require both points to be open to fire 8 times in a distributor rotation. How does that happen with only four lobes and the points in parallel? If the points are in series, then the one condenser would always be in the coil circuit. Edited March 22, 2019 by Frank DuVal (see edit history) Link to comment Share on other sites More sharing options...
Spinneyhill Posted March 22, 2019 Share Posted March 22, 2019 (edited) Each point set opens and closes in sequence. 1 open, 1 closes. 2 opens, 2 closes. 1 opens etc. They are 45o apart. This is from p. 934 of Service Station and Motor Mechanics' Manual, 1940, George George, A.M.I.A.E., M.S.A.E., M.I.A.M., F.I.C.A. Angus & Robertson, Sydney and London. Update 24 Mar.: Joe has corrected this below and I have posted again. The natural state of the circuit is open. One set of points close and open to fire a plug. Edited March 23, 2019 by Spinneyhill (see edit history) 4 1 Link to comment Share on other sites More sharing options...
FLYER15015 Posted March 22, 2019 Share Posted March 22, 2019 I want everybody to give "Spinny" a "LIKE" for this clarification. Lets all help drag him over the 1K mark It is clear, concise, and to the point. If ya don't get it now, we don't have the time or the crayons to explain it to ya. 2 Link to comment Share on other sites More sharing options...
joe_padavano Posted March 22, 2019 Share Posted March 22, 2019 58 minutes ago, FLYER15015 said: It is clear, concise, and to the point. Well, a minor clarification. When the points are closed, current flows in the coil primary winding. Opening the points causes the field to collapse, which is what creates the spark. With two sets of points in parallel and only one coil, both sets of points can never be closed at the same time - otherwise the magnetic field would never collapse and there would never be a spark. Both sets of points are normally held open by the cam and only one set closes and reopens at a time. The actual sequence is: Set 1 close. Set 1 open. Set 2 close. Set 2 open. Set 1 close. Set 1 open. etc, etc. 3 Link to comment Share on other sites More sharing options...
FLYER15015 Posted March 22, 2019 Share Posted March 22, 2019 (edited) Quote You are right Joe. Spinney did not post the whole dissertation, and it may have gone on to "point" that out. So now he's sitting at 999. We need one more "like" to get him over the hump. He's probably a bit down in the dumps now as I just heard he'll have to give up his AR soon. Mike in Colorado Edited March 22, 2019 by FLYER15015 (see edit history) 1 Link to comment Share on other sites More sharing options...
Spinneyhill Posted March 22, 2019 Share Posted March 22, 2019 (edited) Aw, shucks, ya shouldn'a. Um, what is AR? I can't give it up until I know what it is. Thanks Joe for the clarification. It was in my mind that the "natural" state of the circuit would be open, with a set of points closing and opening to fire a plug, but that didn't reach my finger tips. Oh well, 60% mark is OK. At least I participated. Edited March 22, 2019 by Spinneyhill (see edit history) Link to comment Share on other sites More sharing options...
FLYER15015 Posted March 22, 2019 Share Posted March 22, 2019 AR 15. Like we say out west, If your coming for my gun, you had better bring yours. Mike 1 Link to comment Share on other sites More sharing options...
54vicky Posted March 22, 2019 Share Posted March 22, 2019 I do not see a way to give him a 40% to add to his like fund😉 Link to comment Share on other sites More sharing options...
FLYER15015 Posted March 22, 2019 Share Posted March 22, 2019 26 minutes ago, 54vicky said: I do not see a way to give him a 40% to add to his like fund😉 If half the posts on this forum were accurate, I would be finished with my car............ Besides, he is already over the hump. Link to comment Share on other sites More sharing options...
Spinneyhill Posted March 23, 2019 Share Posted March 23, 2019 (edited) On 3/23/2019 at 9:20 AM, FLYER15015 said: AR 15. Like we say out west, If your coming for my gun, you had better bring yours. Mike Don't need an assault rifle. Not a soldier. Almost none of us need one, let alone more than one. Edited March 23, 2019 by Spinneyhill (see edit history) 2 Link to comment Share on other sites More sharing options...
RAH Posted March 24, 2019 Share Posted March 24, 2019 Guys, If I may without stepping on others toes It is my understanding that on Dodge Brothers victory and Std. 6 there are dual points actually in parallel. BUT these points are arranged mechanically so one set closes before the other and obviously the other opens later than the first. This essentially suffices to create a longer dwell period than the cam lobe would provide with just one set of points! Nothing so complex or sinister just a synthetic dwell extension without redesigning the distributer. Yes, the engine will run with just one set of those points. And as has been pointed out previously the condenser is across the parallel set of points. Keep it simple and don't overthink it! Rodger "Dodger" Link to comment Share on other sites More sharing options...
joe_padavano Posted March 24, 2019 Share Posted March 24, 2019 13 minutes ago, RAH said: Guys, If I may without stepping on others toes It is my understanding that on Dodge Brothers victory and Std. 6 there are dual points actually in parallel. BUT these points are arranged mechanically so one set closes before the other and obviously the other opens later than the first. This essentially suffices to create a longer dwell period than the cam lobe would provide with just one set of points! Nothing so complex or sinister just a synthetic dwell extension without redesigning the distributer. Yes, the engine will run with just one set of those points. And as has been pointed out previously the condenser is across the parallel set of points. Keep it simple and don't overthink it! Rodger "Dodger" That is how a normal "dual point" distributor works. In that case, the number of lobes on the cam that operates the points is the same as the number of cylinders (ie, six lobes on the distributor cam for your Dodge). This thread is talking about a distributor where the cam has only half the number of lobes (four lobes for eight cylinders). In that case, the points operate as I described. Go back and re-read the first post. The OP specifically pointed out (pun sadly intended) that he was NOT talking about a conventional dual point system. Link to comment Share on other sites More sharing options...
Spinneyhill Posted March 24, 2019 Share Posted March 24, 2019 2 hours ago, RAH said: Dodge Brothers victory and Std. 6 there are dual points actually in parallel. BUT these points are arranged mechanically so one set closes before the other and obviously the other opens later than the first. How many lobes on the cam in those distributors? Link to comment Share on other sites More sharing options...
RAH Posted March 28, 2019 Share Posted March 28, 2019 On 3/23/2019 at 7:28 PM, joe_padavano said: That is how a normal "dual point" distributor works. In that case, the number of lobes on the cam that operates the points is the same as the number of cylinders (ie, six lobes on the distributor cam for your Dodge). This thread is talking about a distributor where the cam has only half the number of lobes (four lobes for eight cylinders). In that case, the points operate as I described. Go back and re-read the first post. The OP specifically pointed out (pun sadly intended) that he was NOT talking about a conventional dual point system. Sorry Joe. These discussions frequently go off topic and get more complicated than necessary so I should have concentrated on the FIRST query. However in retrospect his original query did NOT specify the number of lobes on the cam, only that each set of points were responsible for 4 of the 8 cylinders. Matt's observation makes a bit more sense where on the Cadillac the separate points must be spaced in a progressive sequence between the lobes so the coil will saturate and collapse twice between lobes. Thus only needing one coil and capacitor! Link to comment Share on other sites More sharing options...
RAH Posted March 28, 2019 Share Posted March 28, 2019 Spineyhill, The DB Std. and Victory distributors have 6 lobes for the 6 cylinders but the dual points are spaced overlapping in order to increase the dwell in a manner like most of the 'dual point' systems. Link to comment Share on other sites More sharing options...
m-mman Posted March 28, 2019 Author Share Posted March 28, 2019 Thank you all for the information. I now understand the Cadillac a little better. Next it's on to figuring out why the Lincoln wont run. ☹️ Link to comment Share on other sites More sharing options...
Willie Wurke Posted April 5, 2019 Share Posted April 5, 2019 I THINK AUTOMOTIVE ELECTRICITY IS FASCINATING Link to comment Share on other sites More sharing options...
FLYER15015 Posted April 5, 2019 Share Posted April 5, 2019 (edited) 26 minutes ago, Willie Wurke said: I THINK AUTOMOTIVE ELECTRICITY IS FASCINATING Yup, if we didn't have any, we would be driving around at night by candle light. A.O.C. Mike Edited April 5, 2019 by FLYER15015 (see edit history) Link to comment Share on other sites More sharing options...
Matt Harwood Posted April 5, 2019 Share Posted April 5, 2019 On 3/28/2019 at 4:10 PM, m-mman said: Thank you all for the information. I now understand the Cadillac a little better. Next it's on to figuring out why the Lincoln wont run. ☹️ Well, if my Lincoln is any indication, it's probably bad juju that keeps it from running. Or maybe just a rotten attitude. Link to comment Share on other sites More sharing options...
m-mman Posted April 8, 2019 Author Share Posted April 8, 2019 The mystery that has never been solved is why some cars are so easy and practically restore themselves. Others are seemingly infested with demons and kick and fight you at every job. It doesnt matter the year or make or even the condition they started out in. Dont they know we are trying to help them? We are saving their lives! Why do they fight us so? Maybe its like a wounded animal. They should be more grateful darn it!!! Link to comment Share on other sites More sharing options...
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