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Arcing points

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Mikep328:
I have no personal experience but I have read and talked to folks that rather than buying new OEM-type/size condensers (now called capacitors), they have purchased known good quality capacitors from the various electronic suppliers.    They are reported to work well/have a long life.  As far as the spec, I seem to recall reading or hearing something like .22uF/1000V AND due to size/fitment that they had to be mounted externally, NOT on the points plate but I wouldn't trust my memory re any of that! 

McCabe-Thiele (Ted):
I've seen car distributors in the past with capacitors mounted on the outside of the casings rather than inside next to the points.

This link shows the 0.22 Micro Farad value.
 https://www.jalopyjournal.com/forum/threads/points-ignition-condenser-question.1237753/

Some interesting comments on this post about the same issues.

https://www.britbike.com/forums/ubbthreads.php/topics/746022/re-what-the-purpose-of-a-condenser-in-the-ing-sys

McCabe-Thiele (Ted):
Interesting arguments on this site about the wiring illustration being wrong before it decends into a slanging match!

https://classicmechanic.blogspot.com/2011/03/ignition.html

Bryanj:
In THEORY it should not matter where on the points lt lead they are fitted and if you fitted an extra in parallel the total capacitance increases so should be better, i tried it on the 500 i sold Ted with 2 rover v8 ones at the coils and the bike did not like it so i disconnected them but as Ted noticed it was too much of a fiddle to remove them!

K2-K6:

--- Quote from: Bryanj on March 23, 2024, 09:27:05 PM ---In THEORY it should not matter where on the points lt lead they are fitted and if you fitted an extra in parallel the total capacitance increases so should be better, i tried it on the 500 i sold Ted with 2 rover v8 ones at the coils and the bike did not like it so i disconnected them but as Ted noticed it was too much of a fiddle to remove them!

--- End quote ---

Interesting practical test Bryan. My hypothesis on this is that the performance of the condenser in these system is related to the characteristic fuel burn time, which has largely stayed the same in petrol (refining, octane rating, combustion conditions etc) such that a condenser within this type of triggered HT delivered system needs to have that in defined range to positively benefit combustion.

There's quite a lot of research available (some really good from GM in R&D of Northstar V8) that discuss in this area. Also interesting is Honda CVCC combustion process from their 70s car engine program, itself a precursor to current F1 pre-chamber combustion of extremely lean mixture burning.

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