OK, I have a quandry regarding some tuning terminology. When I was quite young and learning about carburetion I was taught the term and use of the phrase “Plug Chop”.
It seems to have different meaning to different people.
Stamatis, Bingo, right on the money, that’s a plug chop right there. Exactly what I was taught a very long time ago by some very smart guys.
Here’s why I asked what I thought was a stupid question in the first place.
The other day a guy came into my shop, told me that he had pounded out some practice laps in very cool conditions. Then he asked me if I would look at his spark plug and tell him what I thought.
It went like this, he hands me the plug and it's had the threaded portion cut off.
I looked at it and the conversation went like this:
Me: WTF did you do to this plug?
Guy: Haven’t you ever head of a plug chop?
Me: Silent and dumbfounded.
Guy: Well what do you think
Me: I think you destroyed a perfectly good spark plug!
Guy: You don’t know what your’e talking about.
After some time I thought maybe this isn’t the only guy that believes that. So I googled the term “Plug Chop”.
Tons of the responses involved, cutting up the plug including step by step instructions with pictures and videos.
Back to being silent and dumbfounded.
I wish I was joking but this is real. Think about this, in the last 4-5 months I’ve had to tell more than one adult male how to just change a spark plug.
It only got worse when I googled “Plug Chop” and found many adhering to this theory, as I said complete with step by step instructions including pictures and videos.
If after every tuning you need to do a “plug chop” it will get very expensive Google says to do it to see if you have tuned it right and you cut it open to see id you have done it right… Idk really know this never heard of it acually
@KartingIsLife is correct, although we all refer to it as shutting down and reading, in reality the term comes from the actual step of sawing off the threaded portion to expose the insulator and read the ring at the base, there is a specific color and depth you are looking for, much more reliable than reading the surface.
That is a technique that was commonly used in the past, especially in non kart applications. Even back in the days when EGT and lambdas were not common, in a kart you’d still have access to better indicators (read piston ceiling, exhaust flange, etc). In other applications like multi-cylinder engines in motorcycles, quads, snowmobiles etc where access to engine vitals is difficult or time consuming, cutting up a cheap spark plug (that you’d buy new just for this specific test) is a quick and reliable way to confirm jetting. Not really meant for today’s $50 mini plugs