Condenser Replacement

[glasspacks]

FYI, was looking in the Stovebolt site, a discussion about replacing the " ignition condenser " with a capacitor.  It appears that DIGIKEY offers what may be a suitable part.

.22 uf 500v or so, does not look like a condenser but does the same job so they said, and really cheap.

May have to be mounted outside the distributer...…..

Worth a look.

Glasspacks

[Merle Coggins]

I don’t see why that wound’t work. An “ignition condenser” is just a capacitor in a fancy case for easy mounting

[kencombs]

The only issue may be heat and vibration resistance.  that is the only 'special' requirement for automotive condensers/capacitors.    One thing I've had problems with is locating the actual capacitance of automotive caps. 

 

Once you know that there are a lot of parts that will work.  They don't have to be mounted inside the distributor.  Drill a hole for the lead and mount on the outside and seal up with a little rtv.

 

There is a surprisingly small ran.ge in the actual spec of those I have found.  NOS condensers for GM and Fords are much easier to find.  I've replaced Kohler and Onans with Chevy.  Works fine. Bet it would Dodge too.

[50mech]

There are several considerations here, I was just discussing the same thing in the Chinese autolite plug thread.

 

Condensers run .2-.33 uF

 

Considerations;

1. Increasing the lead length actually makes a big difference here. Even it's position relative to other metal.

I'll link Alan Hale here;

http://www.austin7club.org/Ignition Condensors.htm

Last paragraph explains this.

So lengthening the lead to remote mount means you'll need to tune the capacitance anyhow.

Result of the fact that a wire is an inductor which basically has the opposite effect of a capacitor and when you're only dealing with .22uf a length of wire can basically cancel it out.

 

 

2. Electrolytic is a poor choice , they were only ever made this way because back when that's what was available, and even until fairly recently it's all that could do large voltage spikes.

Problem with them is number 3

 

3. Heat and vibration resistance are factors...but anything... All but dry film electrolytic handle it better than the paper oil al/electrolytics that are used.

I'd say the digikey ones are a toss up...poorer type (dry film) than an actual condenser but likely made much better than recent quality condensers and likely still better than an NOS condenser that's been on a shelf for 40 years.

 

MlCC ,. Tantalum, and others have downsides that make them unsuitable.

 

Anyways I'm trying right now to spec a great replacement that would last 4 lifetimes of a car.

 

Just need to get measurements on the original condensers to match package size somewhat.

 

 

 

Edited August 16, 2020 by 50mech

[PT81PlymouthPickup]

I have two on the bench. #s IG-3927-A and IG-3927G. The 2 cans both measure 11/16 (.6875) in diameter and average 1.67 long. If you add the boss where the wire protrudes, the overall length is about 1.750. These condensers have a welded on bracket with 3 holes. One for a mounting screw the other two for alignment on the breaker plate.

[Los_Control]

I have a airtex model here, 5H1007 measures 1-1/8" long and 5/8" diameter.

 

 

[50mech]

Perfect, should be able to come up with something in the next couple days... probably a few something's

[50mech]

Actually already I've found a Japanese made nichicon poly film axial snubber with a good dv/DT rating that could be fit inside the original cases.

 

As well as a US made Cornell dubilier of the same type.

 

You could strip an old one drill a hole in the back and solder one lead there

Then solder a wire to the other lead and run it out the original hole. Stabilize it all by epoxy filling and slide the front disc back down the wire.

 

I'll make an order this week, make one and first person who wants to try it is welcome to it, just cover shipping it to you.

 

Pm me.

[DJ194950]

I always thought that Guinea Pigs got at least feed for their efforts.

 

Human test subjects get paid money. Not a lot unless a lot was at stake. Their life for example.

 

Now you ask them to pay to test it for you?    Just kidding! !   ?

 

At least your efforts and expenses are included And appreciated!!  ?

 

DJ

[Los_Control]

While I complain the loudest, I would be poor test subject. I only start and move my truck in the driveway at this time, you need someone to drive and test them.

[50mech]

I can't even test it myself, around me points only last until I find them.

Though I have no doubt they'd be vastly superior to what's available in condensers right now.

[Los_Control]

Going to send you a pm, I propose I am a poor test subject. I will pay you what it cost to make and shipping and test it what little I can. I imagine any input would be better then none and the more sources for input the better?

I keep my truck in some kind of running driving state so I can move it and work on other vehicles. soon will need to install the radiator and test for leaks make sure the new T-stat keeps correct temp when idle for 2 hours. ... with my doghouse off, is very easy to get to the distributor to work on if needed.

[50mech]

That works, no chance of roadside failure. 

We'll try it out.

[Los_Control]

I swear cars have personalities. I have to start my 49 dodge and move it tomorrow,  to bring in the wife car Lady Belle.

2 weeks ago my off topic truck was giving starter issues, Last Saturday wife drove to New Mexico and made it home Tuesday  with zero issues ... now the starter is dead in the driveway.

I love this car that she got my wife home, then broke down.

 

I swear it is like children, you buy one a pair of shoes and the other wants a new pair of shoes also.

 

I have some starting and stopping for the 49 dodge in the near future.

[50mech]

Haha yep.

Well, notwithstanding the solder joints required for assembly the caps themselves have roughly a 45,000 hour life expectancy at the op temp and 3 times the voltage in this application.

300 per billion failure rate.

Aerospace grade, so probably overkill but hey....