From Wikipedia, the free encyclopedia
Jump to: navigation, search
WikiProject Energy (Rated Start-class)
WikiProject icon This article is within the scope of WikiProject Energy, a collaborative effort to improve the coverage of Energy on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
Start-Class article Start  This article has been rated as Start-Class on the project's quality scale.
 ???  This article has not yet received a rating on the project's importance scale.


This article has had Distributor Cap Merged into it. Judgesurreal777 22:42, 4 March 2006 (UTC)

is an ignition cap the same as a distributor CAP?[edit]

is an ignition cap the same as a distributor CAP if not wha'ts the difference?

Karlos Romni 22:32, 14 December 2006 (UTC)

This article still contains several misconceptions: 1).-it says that ...Spark plug wires, which need routine replacement due to wear... This is not exact. Since the 80's, the metallic conductor in the core of the spark plug wires, which is spirally wound to avoid causing electrical interference, made the older "conductor" wires made with silk or other materials coated with graphite or similarly conductive coatings obsolete. The main reason for spark plug wire replacement was the degradation of proper conductivity (or excessive resistance) of that type of conductor. Also older wires had insulation made of older types of plastics, which were prone to hardening and cracking after some years of underhood temperatures; but newer wires came with better plastics or silicone insulation, which now endure the whole life of the vehicle or even more in good condition. But the practice or replacing the ignition cables has been kept as part of the so called "tune-up", which is no longer needed or desirable, but keeps the shops busy with unnecessary replacement most times.

Article also incorrectly points to heat and "vibration" as main causes of distributor cap failure, when in reality it is the heavy pitting of the connection posts and the carbon traces inside cap the main causes of replacement, together with central rotor contact on cap becoming too worn. Vibration does never damage a decent distributor cap, unless the attachment springs or screws fall down, which is not easy in most vehicles. Alfredo M Claussen —Preceding unsigned comment added by (talk) 16:54, 17 June 2010 (UTC)

What spins the rotor?[edit]

Where does the force come from that spins the rotor in the cap?

from the main engine shaft, or a side shaft connected directly to the main shaft via cog-wheels. Ai.unit (talk) 14:23, 15 January 2008 (UTC)

When moist gets into the mechanical distributor[edit]

I suggest adding this paragraph to the article:

Cars that use the mechanical distributor often fail if they run into ponds (like when it rains heavily) and that's because the water that leaks inside the distributor shorts the electric current that should go thru the spark plug, and reroutes it directly to the body of the vehicle (aka earth), and this in turn causes the engine to stop due to the fuel not being ignited in the cylinders. This problem can be fixed by opening the distributor's cap and wiping the cam and the contacts dry with tissue paper or by blowing hot air.

Anybody minds?

Ai.unit (talk) 14:30, 15 January 2008 (UTC)

OK. I added it. Ai.unit (talk) 03:25, 1 March 2008 (UTC)

"Was a wonder in its day."[edit]

"This ignition was developed by Charles Kettering and was a wonder in its day."

What? dosent seem to make sense, and dosent really need to be written there —Preceding unsigned comment added by (talk) 19:25, 19 May 2009 (UTC)

Graphics/Pictures Comments[edit]

  1. There is no photo of a complete distributor.
  • distributor cap, rotor, points are shown individually
  • condensor and plug leads NOT shown
  1. The pictures currently on this page are pretty poor. There is a much better picture of a distributors outside, '"Verdelerkap.jpg", in Wikimedia commons.
  2. There is no photo of the inside of a distributor. Need to show points, 'condensor', centrifugal/vacuum advance mechanism etc.
  3. Drawing or cross-sectio showing the physical relation of parts to each other would make distributor easier to understand.
  4. Photos of contactless 'hall effect' and optical 'points' would be good -- (talk) 13:34, 27 October 2009 (UTC)

Available graphics on commons[edit]

Photo of distributor complete with cap

Photo of point mounting plate removed from dist. nb DUAL points

Photo of distributor on motor, c/w high tension leads

-- (talk) 12:51, 28 October 2009 (UTC)


On a 'Widescreen' there is a huge amount of white space at the bottom of the screen. The pics ( breaker, disrib. cap, rotor button) may look better in a 'gallery' across the bottom of the screen? Distributor however should stay at top, right. -- (talk) 05:43, 30 November 2009 (UTC)

Any resistors in a distributor cap?[edit]

Is there supposed to be 16K ohm resistance from coil contact in distributor cap to rotor contact inside distributor cap in a 1993 Geo Prizm (toyota Corolla)? — Preceding unsigned comment added by (talk) 02:28, 30 November 2013 (UTC)

Spark[edit] (talk) (couldn't remember my login details) The picture shows points and a distributor, with a spark occurring in the distributor. Is this correct? Surely the points have the spark and the distributor should ideally not have a spark? — Preceding undated comment added 14:12, 31 December 2014 (UTC)

The spark is undesirable but it does actually happen. As the rotor approaches the nest terminal (post), a spark jumps ahead in its eagerness to form a circuit. This is one of the major causes of the post wearing down. The spark also introduces a bit of undesired randomness to the ignition timing. These are among the reasons why new cars now have a coil on each cylinder and no distributor.  Stepho  talk  07:16, 2 January 2015 (UTC)

Question regarding diagram[edit]

From what I understand, the distributor will send secondary voltage to the spark plugs in "firing order." The numbers on the output caps read, clockwise, 1, 3, 4, 2. There are no numbers on the spark plugs, but assuming their position indicates their number, then read left to right we have spark plug #1, sparkplug #2, #3, and #4. Assuming that the rotor arm only moves in a clockwise direction, as indicated by the arrow, spark plugs numbers 1 & 3 will be "fired" before spark plug #4, and spark plug #2 will be "fired" last. Is this correct? Is this always the "order" the spark plugs are fired?

If I'm correct, is there a way to indicate this in the text, or to indicate what the spark plug numbers are (or how the numbering is done)? Ileanadu (talk) 15:15, 8 April 2017 (UTC)

There ought to be an article on firing order. For inline four cylinder four stroke engines there are only a couple of orders that make sense - largely depending on the shape of the crankshaft. For engines with more cylinders, there are many more options. Andy Dingley (talk) 16:01, 8 April 2017 (UTC)