There has been an unexpected development in the Condenser Project. Recently 2 of them failed. And before I go any further, if anybody has any trouble with these, please contact me. I'll send a replacement for you at my expense. My intent has always been these should last a long time and also (more importantly) this project was and still is strictly a non-profit affair with any monies that exceed my expenses going to future work on Stovebolt improvements. If this or any project I initiate loses money, c'est la vie.
What caused this? I can't be certain, however I learned this summer the maker/distributor of the brass I've been using started putting a coating on it (wax based) sometime within the last year (to prevent oxidation and keep it looking "pretty") and we all know brass will oxidize given time, humidity, etc. The coating (or oxidation if that occurs) somewhat reduces the ability of brass to conduct electricity and it is possible this could have caused an intermittent loss of conduction. When I disassembled condensers made in China, I noticed they all had questionable capacitor to ground connections (one reason I believe so many of them fail right out of the box or soon after they're installed). What else might happen? An internal problem in the ignition coil or a failing coil could be the culprit. Also I expect a free-hanging spark plug wire might create the same sort of problem as could other similar ignition problems. Some of that has recently been mentioned and discussed here. And of course we can't rule out a manufacturing defect.
At this point it is important to tell you the capacitor I selected is "self-healing." Most capacitors when fed enough voltage to ruin the dielectric layer will either die instantly or go into a very rapid downward spiral. Some will bulge at the top or sides and I've seen several electrolytic capacitors explode. Mine won't do that. If you feed a self-healing capacitor enough voltage to cause an internal failure, it will first try to repair itself by clearing the damaged area...that being the spot where the dielectric is compromised and the internal short has occurred. In my experience a self-healing capacitor which has suffered a compromised dielectric will restore itself and will be still operating within reasonably acceptable limits (however not like new again)...but only up to a point, naturally. In case anyone is wondering the OEM condensers will fail the same way...the exception being they die right quick.
In the case of the two failed capacitors, one has lost >50% of capacitance (from .22uF to .10uF) and it was one of the very first of these I made. The other one (a newer one) has lost between 14 and 15%, dropping from .22uF to .185uF. The loss of capacitance (not surprisingly) caused the points to fail in both cases. There isn't a wide range of acceptable values. Sun data from the 1950s and 1960s tells me the ideal value is .22uF with a low point of .21uF and an upper limit of .25uF and other sources gave a slightly different lower limit of .20uF...but nothing below that. I can tear the capacitors to bits and look inside, but the damage might be a microscopic dot the size of a grain of sand and even if I find it, I still won't know what caused it.
So here's what I've decided: 1. If a failing coil or some other ignition system problem caused these failures, that's both uncontrollable and in many cases unavoidable. Even if it is a new coil, it could have hidden fatal defects. To my knowledge only one brand of coil is still made in the USA and the Chinese stuff...well, you know what that is. 2. if intermittent connection due to coatings/oxidation/etc is causing problems, that can be remedied. I have now added a solder ring around the part where the attaching screw goes and that should stop any problem with questionable conduction. If you are using one of these and you want to do the same thing, please go ahead. Sand the brass well with fine sandpaper (220 grit or so) and using rosin core solder, make a ring around the screw-hole as you see I've done in the image below. Solder will bond well to the brass (if it is cleaned as I mentioned) and that will prevent it from oxidizing or losing connectivity over time. 3. from this point forward, I'll look into other connection possibilities.
If you have any comments or questions, please let me know.
Last edited by Jon G; 09/25/20214:50 PM. Reason: forgot image
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
I started driving a 1950 GMC pickup to school in1957 and it was just common practice to change points and condenser at the same time. I later drove Y-Blocks for almost 20 years. I don't think that I can say that I ever had a condenser to fail. I have had coils that would swell up and short out when they got hot. I still have a bunch of old vehicles and have a enough NOS Delco and Holley to last the rest of my life. NOS Delco is still listed on eBay all the time. I wouldn't consider Chinese ignition parts.
I have been attempting to find NOS AC-45 and AC-46 plugs. Oh I have found some but the sellers are wanting $18.00 to $27.00 each plus shipping. Not gonna happen! An old friend and mechanic friend of mine that did some work for NASA told me that years ago NASA requested that all spark plugs had to have resistors in them, Thus the R in front of the plug number. The non resistor plugs were affecting the radio signals from space. I remember my brothers full house 57 Chevy. We could tell when he was coming down the road to the house by the TV crackling and messing up the picture. The same was true on our AM radios in our cars, we had to tune the channel exactly on the station or we got ignition buzz and pops. I wonder if that would be a problem today with the many radio wave links and FM. Ed
Currently making 1954 3100 better than new and Genetics
I don't think copper anti-seize would be as helpful, Ed. What is needed is a non-oxidizing bond between the brass piece that the retaining screw will bite into. Solder should work and I'm also looking into alternatives using copper. I'd suggest using a lock washer if your screw doesn't have one. That will add a contact spot.
Another member is helping by looking into alternative capacitor choices. As I've said before, that decision is a see-saw. You need one that works at high temps, you need one rated for .22uF, you need one that's a certain size, you need this and that and soon you learn the choices aren't as plentiful as you had hoped. But I am positive the answer is lurking...
Yes, Greg. If you can, that will be good. Please send a PM so I can send a replacement to you.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
Ron, there are many variables on coils, but primary at around 1.2 to 1.5 ohms ought to be ok and secondary at around 5000 ohms up to as much as 10,000 ought to be ok, although the resistance rating isn't really what matters the most in coils. Still it is a guidepost and I'd say your readings (I'm expecting the 9.1 really is 9100) should not indicate a problem. Mainly you're looking to see if you have an open primary or secondary (which would tell you that you have an open or dead winding). Your primary and secondary windings could have been done with different size wire. If that's the case, if the secondary was wound with larger wire, the resistance will be lower...all manner of things enter into this.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
Hi Folks, Following study and discussion with others I've decided to change the condenser. Before I tell you what I've done, please let me start by saying I'm not at this time condemning the original unit. A handful of courteous people helped me with the revisit of the whole scheme and there was general suspicion there were possible reasons for failure not related to the capacitor. Some of those have already been mentioned.
If you purchased the original condenser and it has failed or if a sudden change in performance suggests to you it is failing, please contact me via PM or email (jon_goodman@yahoo.com). I'll send you the new one as a replacement as soon as I can. It was always my hope none of these should fail and for 2 or 3 of these to have done so is both surprising and at the same time concerning enough that I've revisited and re-studied the whole scheme. I'm not sending the new ones out to everyone who purchased because several people have told me theirs are working fine. If yours is bad and you want to mail the other one back, that's okay. I'll re-use the brass piece and I'll test the capacitor and add that to the study data.
There are some images below showing the new v. the old. The new capacitor is larger...that is to say taller and wider, but the length is the same. Fortunately it still fits as it should. I'll be looking into a different mounting design, but the reason for that is simply to make certain this be used in other distributors. For the time being, I'll just concentrate on the 216, 235 and 261 applications. To eliminate any possible connection concerns (from oxidation, etc), two things have been changed: a separate bare copper wire goes from one terminal of the capacitor back to the mounting area and is soldered to a tiny silver-plated piece which is also soldered to the mounting plate. The ground connection (obviously essential) was thought to offer the chance of intermittent or limited conduction in the original model, and for any capacitor an intermittent connection can be destructive. I'm also awaiting delivery of stainless steel screws and stainless internal star lock washers, and you will receive one of each with the newly designed condenser to make certain your ground connection is as good as possible. My sincere suggestion is to clean the area of the distributor floor with a paper towel and solvent before mounting your condenser...no matter what type you use. I can't emphasize enough the need for a complete and proper connection.
For anyone who is curious about a few specifics, the new capacitor is a snubber type. The maker of it and other educated and generous folks who were kind enough to offer help and advice believe this type will work better for this particular application. I don't disagree at all, by the way. Making this change, we give up the high temp rating of the original capacitor by 15 C, however even if the internal temperature of somebody's distributor reaches 110 C or 230 degrees F (this truly should not happen), the voltage reduction will still not knock the capacitor out of working limits. The values are 630V DC and 400V AC so the degradation at 110 C would make the AC voltage 275 (250 being the max I think should be expected) and the DC voltage 433. What else? The tolerance decreased to 5%, which is a very good thing. And the expected life is 200,000 operating hours. The red one was 300,000 operating hours, but if maximum life is attained the difference becomes academic. If you run your truck 3 hours a day every single day of every year, 200,000 hours equals 182 years. What else? Ah, the size. I've mentioned that, but I was careful to hunt until I found one that was as small as possible. Some of the snubbers are larger and would have to mounted externally. I think that's about it. I'm making these as time allows. If you've asked about one, or if you've sent payment, this amended version is the one that will be sent to you as soon as the stainless steel screws and washers arrive. If you were one of the people who sent the original condenser back to me, then I'll be sending you one of these at that time. And as mentioned before, if the one you purchased previously has failed or if you have reason to believe it is failing, please contact me.
And thanks to everyone for their support and help...
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
33 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.
J Jon G Online 'Bolter They'll be available later this week. I can't honestly answer your question. The most important thing is capacitance (in uF value). GM said condensers for their distributors should be between .18 and .23 uF and Ford said .20 to .25 uF. Don't know about MoPar. Most imports, some aircraft, tractors, etc used .21 and that actually became the standard (within degrees---the old type long ago were accurate but had devolved into being very inaccurate). And the ideal value also depends on the nature of the ignition coil.
And in my experience it is a very fine line. .18 uF may possibly work but .178 uF doesn't work. When I checked the old can type condensers, they were all over the place...from something like .09 to .26 uF...a wide range but not an accurate range. .21 uF was chosen because it seems to work best for most vehicles and is pretty much in the center of what GM wanted. My goal is to make your points last as long as possible without trouble.
Here's the deal: the wrong capacitance will cause points to burn rapidly. Too much capacitance will cause metal to be deposited on the mounting side of the point assembly. Too little capacitance will cause metal to be deposited on the arm side. As for made in Mexico v. made in China...offhand I'd guess made in Mexico might be better but in fairness I didn't have any of those to look inside, so I don't know. The ones from China should just be avoided.
Another quality post. Real Trucks Rattle HELP! The Paranoids are after me!
