UK Karting - Notice Board (2-Stroke Karting) : Re: Comer Spark Plugs

Notice Board (2-Stroke Karting)

Re: Comer Spark Plugs
Posted by 'itpro' on 27 Oct 2010 @ 15:45

| View Message Thread | Reply to this message |

itproJoined: August 2001
Total Posts: 6
[ View User Profile ]

You may be confused about the meaning of the words Hot and Col Plugs.

The concept is that the 'hottest spot' on a spark plug is the tip of the inner electrode. It is (usualy) surrounded by a ceramic collar which stretches all the up to the top of the plug. This ceramic shound cools the tip of the plug. Again, usually, the more that tip is shrouded, the COOLER it runs. The 'cool'/'hot' refers to the temp of that Electrode.

Thus, the temp of the plug tip is not ALWAYS directly related to the temp of the whole engine (the bit that you measured).

However, having that tip at the 'ideal' temperature CAN (does) alter the perfomance of the engine. An if the tip is too 'cool' it can fail to clear the oil arriving at its 'tip' and may lose you power.... an over-hot tip can lead to the fuel air mixture detonating BEFORE the spark arrives (like in a diesel): this is often called 'pinking' and you can clearly hear it happening. It's when the fuel burns earlier in the cycle than ideal AND.... the sudden uncontrolled ignition of the mixture stresses the top of the piston and also focusses too much heat directly below the plug which can MELT the top of the piston.....

So.... plug temp is CRITICAL to good and safe performance.....

The rule of thumb is usually that you need a 'Hotter' plug in cold damp weather and a 'Cooler' plug in the height of summer. Think of it as needing to warm up the air and disipate the moisture in bad weather; it's not the REAL reason but it makes it easy to remember.

So..... run the hotter plug in wintery conditions and the cooler plug in summer ones.

Please note: this is a ROUGH explanation and crude rule-of-thumb! But it works!

Ian

Message Thread:

Comer Spark Plugs by 'PaulGibson' (27 Oct 2010 @ 15:19)

Re: Comer Spark Plugs by 'itpro' << You are here!

Re: Comer Spark Plugs by 'k44tng' (27 Oct 2010 @ 15:51)

Re: Comer Spark Plugs by 'PaulGibson' (27 Oct 2010 @ 16:24)

Re: Comer Spark Plugs by 'k44tng' (27 Oct 2010 @ 16:49)

Re: Comer Spark Plugs by 'PaulGibson' (28 Oct 2010 @ 10:33)

Re: Comer Spark Plugs by 'MVJ' (27 Oct 2010 @ 16:50)

Re: Comer Spark Plugs by 'John' (27 Oct 2010 @ 17:01)

Post a Reply:

You may post a direct reply to this message which will appear in this thread.
To post a new or unrelated message use This Form. Top of Page
Notice Board Index

[ UK Karting Main Index ]


News	Karts & Karting	Notice Board	Market Place	Companies Directory	Tracks Directory	Events Calendar	Race Results	Photo Gallery	Links