100,000 Miles Spark Plug

[HTSS_TR]

How do you calculate the number of sparks a plug will do in 100,000 miles in a 4-cyl engine. Assume that average speed over that mileage is 30 MPH at 2,500 RPM.

To go that distance at 30 MPH it takes: (100,000 x 60)/30 = 200,000 minutes

Total RPM: 200,000 x 2500 = 500,000,000 RPM

One spark per RPM so the total sparks is 500 millions.

Imagine that a plug does 500 millions sparks over its lifetime for less than $10-15 each.

Something likes park plug is so trivial nobody pay attention, but looking at the detail how it works is really open my mind.

 

[simple_gifts]

One spark per revolution? not.

I did once calculate the number of revolutions my !echo! probably has done. Quite a testimony to a 225 lb contraption.

 

[Joseph_S37]

based on what I know, i believe each plug will only have 1/4 of the 500 million sparks each.

SOmeone correct me if I'm wrong, I just took a quick look at it.

But never the less, that number of sparks is still quite impressive, and for the cost of plugs, it basically costs almost nothing per mile.

 

[Rick in PA]

Yup, back when I was young I had a regular trip I had to make that was 100 miles. Your mind wanders (wonders?) on such a trip. Anyway I worked through a mental calculation on how many time the breaker points in the distributor opened and closed. It was a surprisingly big number. I just recalculated it, V8 (4 sparks per revolution), ~3000 RPM, 120 minutes = ~1.5 million, yes million, make and breaks. No wonder we have electronic ignition.

Materials can make a tremendous difference in some of these applications.

 

[gathermewool]

one spark, every other revolution in a four-stroke, coil-on-plug engine. The RPM is revolutions per minute. So, on a piece of paper do the rail-road method until the units cancel out to just sparks.

 

[Rick in PA]

I get about 150 million.

Assuming at 60 MPH the motor is turning 3000 RPM.
One spark every second revolution for a 4-cycle.
Every minute the engine turns 3000 times, any given spark plug fires 1500 times and the car travels 1 mile.
1500 sparks/mile X 100,000 miles = 150,000,000 sparks
(The miles cancel out in the equation, thank you Prof. Buzzard, he was always on us to keep our units straight).

Nice little mental exercise.

 

[tommygunn]

All those million sparks are nothing once the engine is fully warmed up.

It's the first few thousand sparks per trip that wears them down!

And Some 100k plugs can be had for as little as $6!

 

[GhostFlame]

Sometimes inquiring minds have to know!

How about a brake job for say $200 per axle. And in 20000 miles how many time do those things safely stop 3 to 4 thousand lbs. For fractions of pennies per stop. My head is starting to hurt.

 

[Nick1994]

Originally Posted By: tommygunn


And Some 100k plugs can be had for as little as $6!
I assume the expensive spark plugs he's talking about his Lexus, my Camry used similar (if not the same) plugs that are double platinum or something. Not cheap.