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MG MGB Technical - Cheers to a film cap for the dizzy

From the talented mind of Peter Burgess, I replaced the condenser in ny dizzy with a film cap.

Relying on my amplifier background, a film cap is always preferable to a 'lytic and to the squirrelly condensers that seem to be cropping up.

For purists its too large to go inside the dizzy and has to go directly on the coil then to ground.

I was looking for a solid solution to these horror stories about condensers. What I didn't expect was how much better the car is at higher RPMs.

The only thing I liked about electronic solutions was at higher RPMs the car just went and never struggled as it does a bit with a mechanical 25D even with rebuild and recurve.

Adding the film cap surprisingly appears to have had the same effect. Best of all they almost never, ever go bad.

Just a FYI to those here with mechnical dizzy's.
Max71

Ok, More information needed. What do they cost?
Bruce Cunha

The shipping was more than the cap so I bought two. I think they were $5 each. Stateside I had to go through Newark.

MKP1845422104

Peter makes these up for people. Hope he doesn't mind. Shipping a cap to the states seems like a lot of work.

Here's a shot of the finished product. I'm pretty particular about the engine bay, but you could hide it better than I did. The performance difference is worth it.

Max71

FWIW, standard condensers for distributors are not electrolytic.
paulh4

Hi Paul, I know. I was just commenting. I took one apart once. Its just a roll of material with amount being the Ohms. I could never get a stable reading of one with a DMM.
Max71

A capacitor should test open-circuit, unless it is faulty. There are two sheets of foil in the roll, separated by a very thin insulating sheet.

When first connecting a meter, an analogue at least, and especially if you connect then reverse the connections, you will get a pulse on an ohmeter as the capacitor charges up from the meter battery. The larger the capacitor the larger the pulse, small values won't be visible, but you should see the effect on an ignition capacitor.
paulh4

Just got an email from Peter. He is not making these any more due to time constraints. Said they are easy to make, but did not give any details.

Any of the electrical smart folks know how to make these?
Bruce Cunha

Paul - Your explaination of what's in that condenser (old English for capacitor) is obviously correct. Dedicated Capacitor readers are quite expensive and not necessary for casual user. I can pulse them and get different reading across 4 different condensers. I wonder what the +/- tolerance is and if that's the reason people are having issues.

Bruce - If its ok with Peter, here's the ultra simple recipe:

1. Order the film cap I called out above.

2. Remove the condenser from the dizzy.

3. Prep the film cap. Peter uses epoxy and cuts the solid leads and uses stranded wire. I did not do that mainly from electronics experience. Not disputing anything from the mind of Peter. Caps in electronics need to remain at a certain temp range. Not operating near the max the better. With the engine compartment generating the heat it does I don't want to decrease the cap's thermo venting by adding more insulation.

Therefore, I used shrink wrap on the body just to prevent rubbing and abuse. Then I placed shrink wrap on the leads and solder the terminals after crimping for a permanent fit.

4. Film caps are not polarity sensitive. Therefore which ever you want to be the ground and the coil end is up to you. So a lug and a push on connector for the coil end. For audio we place the writing pointed to the direction of signal. In this case, I doubt it matters. So one end to the (-) of the coil (side the dizzy lead goes) the other to ground. You can see it in the picture. NOTE: This is for a negative ground car.

That's it.

Now if you want to hide it better you can use Peter's method of cutting the solid leads and attaching stranded, jacketed wire.

Let me know if this isn't clear. Its really a surprising performance boost at least in my case. I'm using a 25D.

I imagine its the same for a 45D. Paul?
Max71

Paul - Your explaination of what's in that condenser (old English for capacitor) is obviously correct. Dedicated Capacitor readers are quite expensive and not necessary for casual user. I can pulse them and get different reading across 4 different condensers. I wonder what the +/- tolerance is and if that's the reason people are having issues.

Bruce - If its ok with Peter, here's the ultra simple recipe:

1. Order the film cap I called out above.

2. Remove the condenser from the dizzy.

3. Prep the film cap. Peter uses epoxy and cuts the solid leads and uses stranded wire. I did not do that mainly from electronics experience. Not disputing anything from the mind of Peter. Caps in electronics need to remain at a certain temp range. Not operating near the max the better. With the engine compartment generating the heat it does I don't want to decrease the cap's thermo venting by adding more insulation.

Therefore, I used shrink wrap on the body just to prevent rubbing and abuse. Then I placed shrink wrap on the leads and solder the terminals after crimping for a permanent fit.

4. Film caps are not polarity sensitive. Therefore which ever you want to be the ground and the coil end is up to you. So a lug and a push on connector for the coil end. For audio we place the writing pointed to the direction of signal. In this case, I doubt it matters. So one end to the (-) of the coil (side the dizzy lead goes) the other to ground. You can see it in the picture.

That's it.

Now if you want to hide it better you can use Peter's method of cutting the solid leads and attaching stranded, jacketed wire.

Let me know if this isn't clear. Its really a surprising performance boost at least in my case. I'm using a 25D.

I imagine its the same for a 45D. Paul?
Max71

Hi Max, I had to resort to Wikipedia to find out what a "film cap" is? It is easier for us simple folk if jargon, abbreviations and nick names are minimized in these threads.
Mike
Mike Ellsmore

Max - capacitors tend to be wide tolerance in the order of 20%. I've done experiments on ignition systems with double and half the standard value and whilst there is a nominal difference in the traces on an oscilloscope there was very little visible variation in the spark itself.

Funnily enough just this weekend a pal and I have been doing some tests setting the points gap in a distributor on the bench using an analogue ohmmeter (which is what I always do when changing points). If you take the reading off a volts or current scale instead of the ohms it gives you the reading in percent, which is relatively easy to convert to degrees. He found that the reading was much higher than one would expect for the gap, and also increased significantly as the speed of rotation increased. My spare gave the correct reading, which did increase slightly with speed - but only when turning it at the equivalent of 4k to 6k engine rpm, which I doubt anyone does when using a dwell meter on the car. I suggested disconnecting the condenser, which brought the reading back to where it should be, and didn't increase the speed. Then with a different condenser the reading was still correct, although like mine it did increase slightly with speed. The distributor he was using had been in the car until he replaced it with an electronic system, so that shows just how much condensers can vary.
paulh4

Hi Mike - I don't know any other technical way to describe the capacitor. If you use the term 'film capacitor' you can find them in various forms. In any regard, I did provide the part number. There are many types of film capacitors or solid capacitors but the differences are mainly for audio. I had mentioned electrolytic capacitors which have a chemical reaction in order to work and dry up over a period of time changing their specs and becoming useless.

There are a few electrolytic capacitors on our cars, notibly on the tach for tachs running 1970 to 1974, I believe. Manufacturers state after 5 years on the shelf (in inventory, unused) they are dried out and should be recycled. In audio if the electrolytic caps are 10 years old they should definitely be replaced. Film capacitors do not rely on a chemical reaction hence much larger but last forever, at least I've never seen one go bad unless the circuit shorted it.

Paul - fascinating as always. Maybe the QC just isn't there with condensers as they used to be. I imagine you could fit an electrolytic cap in its place to stay within the confines of the distributor. Then replace it every 5 years. A decent quality one would be pretty cheap.

I've owned this car all my life and still am discovering new things. I never really thought about the effect of the condenser and should have if I took the time to really study its purpose. Thank again.
Max71

Thanks Max. Now I understand. The terminology was new to me. But now seeing the Film Cap. I understand.

http://www.newark.com/vishay-roederstein/mkp1845422104/cap-film-pp-220nf-1kv-axial/dp/53M8395

Ordered a few and will see how they work on the B and also on the Spitfire that I have been having capacitor issues with.

I do see that they list a 100 max operating temperature. I am assuming that is in Fahrenheit? Wonder how warm it gets under the hood here in CA in the summer?
Bruce Cunha

Looks like they are currently out of stock at Newark. Says they will be back in stock on 7-10-17.

You must have bought them out Max.

I see some available in the UK.

Any other substitutions?
Bruce Cunha

"I imagine you could fit an electrolytic cap in its place to stay within the confines of the distributor. Then replace it every 5 years."

Never had a conventional condenser fail in 50 years!

It gets a lot hotter than 100F in the engine compartment in the UK in summer, let alone America. I've measured mine while investigating concerns about hot coils and on a 30C/86F day it got up to 64C/147F.
paulh4

The operating temp spec on that cap is -55C to 100C.

http://www.farnell.com/datasheets/2050674.pdf?_ga=1.120617611.289494521.1490642281
Steven Rechter

Yes, Celcius. Translates to 212F. All capacitors I know of are measured in Celcius.

Bruce - the link says 565 in stock.

Paul - you are lucky. :-)
Max71

They must have updated that today.

I did run this by Jeff Schlemmer. He feels they are just not up to automotive use. As he said. If they worked better, the car manufacturers would be using them.

Not saying I am not going to try one, but it will be interesting to see how they hold up.
Bruce Cunha

I beg to differ, especially since Peter has been using them for years and I'm very familiar with caps. Film caps are far more reliable and can deal with extreme temps. IMO, The reason the manufacturer didn't use the is because they're too big to fit within the dizzy. Plus we've learned alot about our cars since being made.

That said Jeff did my dizzy so I respect his ability. Just differ on this one.

Just make sure you prep it right.
Max71

I have a condenser on the distributor of the spitfire I am refreshing. I believe it acts as a radio suppressor. I can't think that there is any reason the condenser needs to be inside the distributor.
Bruce Cunha

Many distributors had their condenser mounted outside of the distributor cap.

My 1974 Saab Sonnet had the condenser mounted that way.

See photo.

Steven Rechter

Suppression capacitors are usually mounted with the coil as they are connected to the 12v supply to the coil, not the connection between coil and distributor.
paulh4

Take a look at the original article by Eric Worpe in the "totally t-type 2" magazine, available online every two months. In the August 31, 2015 edition.

http://ttypes.org/ttt2/?s=polypropylene&submit=Search

Actually the suggested coil mount polypropylene capacitor suggested by Eric is slightly different from the one he suggests to mount on the dizzy plate of a T-Type, or the (green) poly cap you guys show mounted on coil is the one Eric suggests for the dizzy plate mounting.

The (yellow) poly cap Eric suggests for the coil mount, connected as how Paul is talking, is LCR brand. In the article picture the "LCR" got cut off in the picture. This is the one I "potted" (I used epoxy) in 3/4" copper plumbing pipe with an end cap, with one lead soldered to the copper, as in the article illustration. Ignore the numbers at the bottom of the yellow poly cap pictured (11-15) as they are just a batch number, and not part of the specification or part number or description.

The green poly cap can be also potted in 5/8" (odd size) copper tubing.


D mckellar

If your car is running well and you reach the point that it is time to do a tune up and replace the points. Please note that I said replace the points - period. If the car is running good - DO NOT change the capacitor. Good capacitors (i.e. the original capacitor) do not wear out. The capacitor in the distributor is NOT an electrolytic capacitor as Paul stated earlier - they are the period equivalent of the much touted film capacitor (they used something like onion paper to separate the two strips of foil). I purchased out TD in 1974 and as far as I know, the capacitor had never been replaced and it never did get replaced until I installed a pertronix (I am lazy and don't enjoy changing the points and going through the gap setting) about 5 years ago. The same capacitor was still working fine at that time and I am confident that if the Pertronix dies on me, I will pull out the points plate that resides in the tool box in the engine compartment and the original capacitor will be perfectly ready to continue it's job as it had before.

I am not sure where the habit of changing the capacitor with the points, but the suppliers certainly made a fair amount of money on discarding perfectly good capacitors.

In addition to the article in Totally T Type, quoted above, one of the member of this forum, Steve Maas also wrote an article stating much the same as the article in Totally T Type. In the article, Steve suggests purchasing a standard 0.22 microfarads, at least 600 volts dc breakdown voltage at any good electronics parts houses (not Radio Shack - they don't even know how to spell electronic, much less capacitor - and they are going out of business anyway).

I will repeat, if it is time to replace the points in your and everything is running good, DO NOT replace the capacitor. Cheers - Dave
DW DuBois

I suppose if the copper acts as a heat sink its ok. One of the issues with caps is overheating. The LCR looks smaller physically however it has the same values which should work fine.

By Googling LCR they seem to be quality caps.

If you can fit a polyprop within the dizzy that would be aesthetically the most pleasing.

I'm unclear on your point since both have the same values.
Max71

Hmm, somehow this got cut off. In the meantime, DW posted. Agreed and later I was told the same. Its not the issue if you get a good condenser leave it alone. Its the issue of unexpected performance gain is the reason for this thread.

Also Paul checked several caps and they were different. Therefore you would need to check a number of them to get one in the target zone for what is produced these days.

It just my preference to get a solid film cap that I know will never break down. You're right DW, all the points I ever bought were either packaged with a condenser or drilled it into the owners head you had to change the condenser everytime you changed the points. Not so sure about that now other than as DW pointed out seems to be more of a marketing ploy. I do know people who's cars dropped dead from bad condensers. I also suspect people don't drive their cars as they did when our cars were new. Hence less stress and torture temps.

In regards to T-page, I agree and found much the same when I took apart a Lucas condenser. Because of modern QC and the limited places that make these and most likely the lack of care seems like its resulted in issues. Maybe back in the day they were fine. I can't remember. But a modern film cap is superior and doesn't rely on the archaic construction.

Naturally, this is all my personal opinion. YMMV
Max71

The Vishay (green) cap is 42.7mm long X 16.4mm Dia.

The yellow VCR poly cap is 32.4mm long X 18.5mm Dia.

Both are rated to 1000V. Several criteria were used by Eric Worpe to come up with the two polyethylene cap's he chose, and that is all explained in the article.

I have one of those original condensers that Dave D talks about here. It IS the same one that was in there when my Dad bought the '49 TC in 1952. It crapped out 2 years ago on a set of points that had been in there a while. The car will still work with it connected, but not run too well, and it causes point to wear out fast. The original Lucas coil does still work just fine.

There are two opposing camps on those old condensers. One group says they have a long lifespan, 60 years or something like that is the number they use. And then, story goes, various sorts of contamination get the better of them, no matter how perfect the climate they are used in or how they are stored. The other group says what Dave D says, that they can last forever. Both groups claim to have superior knowledge over the other group.



D mckellar

"I suppose if the copper acts as a heat sink its ok. One of the issues with caps is overheating."

If a capacitor/condenser has a problem with overheating it's because it is absorbing heat from the engine bay. Capacitors do not get hot by themselves, they do not pass current and experience a volt-drop and hence watts like resistors do.

Putting a chunk of copper round a capacitor/condenser in an engine bay is more likely to make things worse. You should be heat-insulating it, if anything.
paulh4


""" Putting a chunk of copper round a capacitor/condenser in an engine bay is more likely to make things worse. You should be heat-insulating it, if anything. """

Tell us then Peter why all the original style condenser's were wrapped up in metal?



D mckellar

In the heyday of points ignition of the 50's to mid 70's when I used to do hundreds of mostly V8 tuneups in a month, people expected a new condenser when you put in new points. No bid deal, as I never in my entire time doing thousands of tuneups (1950-1978) did I ever so much as once ever install a condenser that did not work right that I just put in. Never had so much as one person come back in between new points with symptoms of a condenser gone bad. Cheap insurance. The good old days when condensers were not crap.

The whole idea of not changing out a condenser unless it is bad is hysterical nonsense. Nobody says that now, (when it seems few parts houses can find decent condensers to peddle) when you install your new points and condenser you MUST toss the old (still working) one in the garbage. Best hang on to it these days in case you need it. You see no matter what nonsense people are peddling today about some condenser that lasts forever, same thing wrecks them today (the ones that are not crap to begin with) as back when I was doing them, and that is heat cycles. Guess what, that is exactly what they used to say in the trade magazines back in the good old days: "Change out the condenser every time when new points are installed, as they have a definite life expectancy based on heat cycles." And, "without regular replacement of the condenser you risk exceeding the heat cycles that can be expected in the normal useful lifetime of a condenser."

And I never saw any condenser that was not inside a little steel can thing.
b fisk

Again, this is IMHO. I'm not trying to convert or convince anyone.

Paul, as always, is spot on. Correct, by themselves Caps don't generate heat but are susceptible depending on where they are in a cicuit (again, electronics experience, not auto). That's why they have heat ratings on them. I have measured caps with a heat gun in circuits to make sure they are within operating values. Usually its the resistors etc that heat them up. Some get scary hot where you could burn your finger yet within operating specs.

Now in a car you have a hot engine bay. D- there is a physical difference between the tape in a condenser and a solid capacitor.

I've run a heat gun on the engine and in summer it can get pretty hot. I don't off hand recall the temp readings. Can an engine get over 212 F?

The cap is not lying on the engine at any rate. Having it by the coil I imagine is significant heat exchange. Next outting I'll measure the cap. Like LED's a heat sink would be best. I did not make mine like Peter suggested due to concerns about temps. I'm sure his way is battle tested. I just use my experience with caps.

B- I used to do that everytime and never thought for a second about the condenser. I've had the car from almost new and in the day don't recall people complaining about condenser failure. These days are not those and the I doubt there are many or more than one place making these condensers. Unless someone is going to carefully manufacture one its just not worth it to me.
Max71

The biggest problem with capacitors in the ignition today as opposed to years past is that new cars all have electronic ignition, in which capacitors are no longer one of the major parts of the ignition. The result of this situation, is that the manufacture of ignition capacitors has been pushed off shore, like so many items sold today and in a push to"keep the cost down" the third world countries that producing them today are producing junk and since there is a very small group of motorists using the capacitors don't have any clout to get better products. Cheers - Dave
DW DuBois

"Tell us then Peter why all the original style condenser's were wrapped up in metal?"

No more than a metal can, I would have said, which was par for the course in 50s capacitors, and needed for the mounting tab to resist fracturing from vibration. Original style still are in a metal can, as far as I'm aware.
paulh4

Paul says-
" Putting a chunk of copper round a capacitor/condenser in an engine bay is more likely to make things worse. You should be heat-insulating it, if anything. "

But a chunk of steel around the original style (lower heat rating) condenser is OK? No offense intended in our discussion, Paul, but it is that error in logic that I was addressing. Caps are not enclosed in metal to give a handy mounting clip, they are enclosed to keep the thing together, which conveniently also allows for a mounting clip and ground connection. Along with keeping it together it also protects the innards from the harsh, corrosive engine bay environment.

Jeff Schlemmer told someone here he felt the poly cap arrangement, as Peter B was selling, "is not up to the task." I seriously doubt he meant that a properly potted (or "chunk of copper around" as Paul describes) poly caps described in the Eric Worpe article, considering that the modern poly caps are superior to the old stuff in every way--once also potted.

If you had one of the poly caps in hand to examine you would understand that they are not designed to be used as Peter B was apparently selling them. That un-potted method would work just fine for diagnostic purposes or short term use, or as a reliable spare to carry. But in regular use, soon the thing would start unrolling like a roll of toilet paper, because that is how they are constructed, and the adhesive used is not meant to keep it together with intense vibrations combined with engine bay heat found in automotive use. At the very least, Peter B should have used some good heavy duty heat shrink tubing around the actual poly cap body to prevent this unwinding.

I will not argue with Max's claim of the poly cap allowing higher RPM's, because that could well be the case in engines that can rev that high with points. More likely most people will not notice any seat of the pants difference, unless they had gotten used to the feel of a bad (partly failed) condenser, and then change. The big difference is that a properly potted poly cap should be quite reliable and long lasting. I did pot the (yellow) LCR poly cap (2 years ago) as described in the Worpe article to mount on the coil and it works just fine.

Since then I also discovered the multi-layer ceramic capacitor, that easily fits on any distributor points plate. I have no association with the makers of the ceramic cap assembly. I have also fitted the ceramic cap assembly in two different cars (4 cyl and 6 cyl) and it seems to work just fine also, but is only 630 Vdc compared to the 1000 Vdc poly cap, and there are some concerns the ceramic one may fail if oil gets splashed on it, or covered in an oil mist.
D mckellar

"there are some concerns the ceramic one may fail if oil gets splashed on it, or covered in an oil mist."

Since the ceramic cap is small, gut the can of a conventional foil cap and mount the ceramic inside.
Steven Rechter

Is that intended to be humorous Steven?
b fisk

I hadn't realised I was coming under attack:) The cap setup I made up was designed by my electrical engineer mate to do the job. With his pedigree in aerospace, aviation, Lockheed Martin, MOD, I trust him implicitly as do all folk who fly in Airbuses or Typhoons :) He designs systems to include manufacture of said system.Take high quality cap. Attach silicon covered wire to each end. Bring leads out one end, shrink wrap two wires. Cut suitable length plastic conduit. Blank off one end, insert cap, seal with epoxy resin and insert plug with hole in. Once resin set dip whole tube into varnish. Allow to dry. Fit to wing away from heat. What is the problem with that? The whole thing looks good and works. It is labour intensive though.
Swiftune sells a messy looking one (one lead from each end for vast amounts of money!
http://www.swiftune.com/Product/535/swiftune-competition-condenser.aspx
Funnily enough I met the guy making the Swiftune ones and he was very impressed with our version :)
Fitting faulty OE caps is no fun!!!!!! I have to sort problems, I don't just have one pride and joy to molly coddle, I look after many many pride and joys for folk and expect them to be reliable!

Peter
Peter Burgess Tuning

"But a chunk of steel around the original style "

It's not a chunk! As I said yesterday it is a (thin) metal can for the purposes of mounting.

Plastic is just as good as a metal can at keeping things together, non-electrolytic types for electronic circuits have been constructed like that for very many years, as the circuit board and the terminations provide all the support that is needed. However larger electrolytics may well have a metal can.

But that's all by-the-by. The fundamental fact is that unlike resistors, capacitors do not generate heat, therefore unlike high-wattage resistors, they do not need a heat-sink.
paulh4

Here's a 1000v 0.22uf mil-spec hermetically sealed cap rated to +125C.

http://www.tedss.com/CQR12A1KG224K3P

http://www.tedss.com/DataSheets/2020/CQR12.pdf



Steven Rechter

I attach a pic of the cap, cap with lower wire bent up to point in same direction as first wire, finished product ready for p-clip mounting. OD of conduit is 20mm cap is 42.5 mm long and 16 mm OD, gives scale of components.
Peter

Peter Burgess Tuning

I could say a whole lot more about this discussion but I will limit it to point out that Mil-spec always rates things for "AMR" temps, while normal everyday civilian industrial electronics specifictions (non military) are listed in "ROC" temps. Absolute Maximum Ratings (temps) are generally based on the temp at which the component is so far out of range that they will cause a device to malfunction or stop working. Recommended Operating Conditions (temp) is the standard (non-military) way electronics components are rated for temp. In other words the 125C Military rating is probably no different from the 100C Industry rating.

Full specs are not given on the Mil-Spec capacitor, so the only thing appealing so far about it is that it has a mounting clip, but more importantly it is potted already, which has been pointed out above is essential for automotive use in this case.

The idea given above of heavy duty heat shrink (around the cap body) for the Peter B interpretation of the totally t-type version is absolutely brilliant, though obviously a metal can would be better.
b fisk

We have used around 40 of the Vishay caps since 2012 and recorded no failures. A fair few have been on race cars where points system is part of the regs. These fitments are subject to rapid underbonnet temperature fluctuations, vibration and g-forces not expected on road cars. Some of the endurance races are 45+ minutes.
The first test ones were on VW campers which run pretty hot in the engine bay! No failures.

Peter
Peter Burgess Tuning

Yeow. This was meant as a tribute to Peter B. Peter, I'm sorry you got dragged into what should have been a thank you. I was just trying to provide help to the community.

Your finished product looks great!

I'm happy with the set up and carry a spare. I use my car as a daily driver. I'll give reports of non-potted performance.

Paul - I only mentioned heat sink to wick away heat. As stated the caps don't generate heat but can be heated up.
Max71

Get a grip Peter B, the only people doing any attacks here are your wannabe followers who don't have a clue about potting of electronic's components, and how or why it is done. Nobody said your thing was not suitable for use in the race cars, now did they?
b fisk

"Is that intended to be humorous Steven?"

Obviously no it was not.

Mounting the cap inside the mountable can and then potting it would be the proper thing to do.
Steven Rechter

Steven, do you even know what the MLCC is? I have been rebuilding motorcycle and aircraft magnetos for about 50 years and so I am familiar with the layered ceramic capacitor thing that some British fellows have recently put together as a condenser replacement. I will be surprised if that is not the ceramic assembly D Mckeller is talking about using successfully in a 4 and a 6 cyl automobile, after also using the poly capacitor discussed here, also. These multi layered ceramic cap assemblies are marketed to the magneto people, but there is zero reason they cannot be used in the standard Kettering points setup as long as the Farad rating agrees, and that I figure is what he is talking about. When you rebuild a magneto or a distributor you should end up with an oil-free environment in there or you have a problem with your bushes. You got a problem if your old distributor is oily in there, too. The point is not to wrap it (ceramic cap) up in a metal jacket, the point is don't waste your time fitting it in a worn out (oily) distributor. There are plenty of magneto and distributor "experts" out there that will tell you that both the poly cap and the layered ceramic cap simply will not work. They say its a hoax, and they don't know what century it is either. The ceramic multi layered cap is about the size of a pencil eraser flattened out to about 1/8" thick. It needs to be mounted on a circuit board using highly specialized soldering equipment because its so tiny. Then you buy that board with the cap already connected so all you do is cut the board to fit and attach (solder) a wire on one side and the other side of the board is ground. You don't stick it in a metal can, you dont stick it in a worn out oil messed distributor or magneto.

I know what these things are but I never tried one yet. No reason the multi layered ceramic capacitor device should not work even much better than a poly cap, and could be easily mounted inside the distributor cap. Now I want one of the layered ceramic caps and will have to dig through my desk and find where to get them. Somewhere in England.
b fisk

"Steven, do you even know what the MLCC is?"

Yes thank you. I am an electrical engineer with many years of aerospace flight systems design, high voltage dc to dc converter design, aircraft power systems design, etc.
Steven Rechter

Let's just close this thread, its become attacking and that is not what it was ever about.

I'll summerize:

Film cap, potted. Done.

Yes milspec is the highest spec.

Let's get back to a community that assists others.
Max71

I am glad you are happy with it Max, a nice, simple solution which many can take advantage of and enjoy fitting one themselves. it always feels good to plan and do a job like this on one's pride and joy.

Problem encountered, poor quality of oe style replacement caps and failure rate.
Solution based on KISS principle. Fit something cheap and safe (will do job!) to solve problem.
End product, suitable cap in protective canister fitted to area around coil not in distributor. This overcomes heat and sizing of replacement component.
Test, fit in road and race cars of all types.
No failures so successful and IMHO the end product looks neat and is functional, I would expect nothing less from Martin who was working with aircraft manufacturers in the UK before he left school and went to University!
He has even been involved with our rolling road electronics and passed on improvements to the manufacturer which have been incorporated in new systems. Martin has that sort of mind which leaves me breathless!
http://uk.linkedin.com/in/mfaulks
I am honoured to supply him with endless cups of tea when he visits us which is always sleeves rolled up getting in close and dirty whether mapping his turbo projects, making electronic gizmos to try or working on our engine dyno installation project.

Peter
Peter Burgess Tuning

Gee Steven you seem to have difficulty following the conversation, don't you? I am talking about the MLCC that comes mounted on a circuit board (not to be potted in an old condenser can) and marketed by the magneto guys, remember?

Max please remember that the ignition condenser or its poly capacitor does not itself generate heat. How many times must I repeat this?

No mil spec is just a different method of rating mil spec items, it says nothing of superior quality, only that the manufacturers of it were desperate for a military contract.
b fisk

b fisk, I have no interest in continuing this discussion with you.
Steven Rechter

For a group of people pretending to have a serious discussion on looking for alternatives to ignition condensers for their road cars, it is quite interesting how you only want to discuss one particular design. It sounds like just another tawdry advert for one product from a particular vendor, with attacks (from the pretenders) aimed at anybody who actually interrupts that advert with real information of interest to the group on the topic. And no, you do not call epoxy and heat shrink on just connections "potting."
b fisk

This is my last post in this thread. I had no desire to post again but I don't like how it's being portrayed by b fisk.

If you would read rather than pontificate and criticize you will see that I mentioned or acknowledge caps do not generate heat however they can heat up. Yet, you still persist. A cool cap is a happy cap and 35 years of working with electronics will not convince me just because someone is persistent.

Sorry to be mean. It's just not relevant nor helpful to people now or in the future who happen on this thread for solutions. The thread wasn't entitled "alternative discussion / methods to distributor condensers'

It was titled what it is and was a public thank you to Peter and hopefully helpful to others to go beyond the recent condenser quality.

As far as pushing something - nothing to push. The only person who actually made them for sale no longer does. So it is strictly DIY.

I fully understand what the term 'potting' is and have had many caps and transformers 'potted'. My reference was to the postings above my summation discussing potting.

Please just leave this thread alone. It is not productive to what the original topic suggested.

I must apologize to all members here from outside the U.S. as sadly it appears conflict is only coming from the U.S. Posters here are quite helpful and knowledgeable, and I personally, appreciate it.
Max71

" I only mentioned heat sink to wick away heat. As stated the caps don't generate heat but can be heated up."

But because they don't heat up, there is no heat to 'wick away'. The opposite effect would occur - i.e. engine bay heat would be transferred into the capacitor more rapidly with a chunk of copper round it than without.

An insulating jacket would make more sense, to slow down the rate at which the capacitor is heated by the engine bay.

But given enough time the capacitor will always become the same temperature as the engine compartment, regardless of what you put round it. That's entropy.

At the end of the day all you can say is that a capacitor mounted in the engine bay - ideally in front of the radiator, won't get as hot as one inside a distributor, which has no air-flow, and is bolted to the engine i.e. probably the hottest part.
paulh4

"But because they don't heat up, there is no heat to 'wick away'. The opposite effect would occur - i.e. engine bay heat would be transferred into the capacitor more rapidly with a chunk of copper round it than without."

Yes, excellent and pertinent point. I should have been more explicit. I would imagine it should run cooler than within the dizzy being in the open cavity between the engine and coil. Again, for the sake of investigation and this thread I'll take random heat checks with mine using a heat gun and report.
Max71

This thread was discussed between 23/03/2017 and 07/04/2017

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