What does 'pinging' sound like?

[cyclecat]

I recently had someone tell me this 'pinging' that everyone talks about is a sound similar to the sound a spark plug makes if you make it spark while not in the engine. Now I know what that little sparking noise is, but what I can't figure out is this - if that is pinging then how do you hear that over all the racket a Nomad engine makes? Awfully small sound to be heard over the lifter noise.

[redjay]

You can hear pinging over the noise of the engine at almost any road speed. Too high a gear and too much throttle will bring it on. Too much throttle in the correct gear also brings it on sometimes. Its hard to describe the noise but usually there is no mistaking it. A few marbles in a tin can shaken vigorously ?

[macmac]

Ever hear a late 70's Toyota run on after the engine was shut off before. This was common on a lot of other cars as well. After a drive somewhere with the engine at full warm, upon shut down, the engine infact would run several beats backwards, and clatter, spit and pop as it did. Needless to say no engine should run backwards.

This is called 'Post Ignition'.

The sounds for 'Pre Ignition' are similar, but the damage is worse, since the engine is attempting to run both forwards and backwards at the same time!

The cause is a too overly lean air to fuel mix detonates the fuel before the spark plug fires. This is something like the way a diesel engine runs, but is just all wrong for a internal combustion gasoline burning engine, that times the spark with a system to fire plugs on time.

As close to any idea I can muster to duplicate this sound with no engine is to fill a can with pebbles and shake it hard.

Usually the conditions to set this up for real are lugging the engine, running the rpm to low for a sudden demand to accelerate. This can happen in most any gear, at most any spped, and is worse in higher gears when a sudden action is called for like passing another vehical, or attempting to ride up a hill where you were already lugging the engine, don't shift down a gear maybe 2, and still run the engine a bit too slow to really go up the hill.

This sound can be there and not be audible to the human ear, and when it is the conditions are extreme. Metals erode where there are sharp square coners, like the edges of pistions, edges of compression rings, and the edges of valve faces. The end result is bits of these parts turning into rough cutting grit, which exasperates the damage.

The damage becomes visable on all the parts mentioned, and in some cases the heat is so hot it will burn a hole thru the center top of a pistion. In the case of burning valves the grinding bits will be caught on the valve seats and face of valves which allow blue hot flames to sear and gas cut both the vlalve face and the seats, removing steel, and causing the valve to loose any abilty to seal, so no more holding compression.

[flightdoc]

I think it's similar to the sound of the old diesels under heavy acceleration from the stop.

[cactusjack]

Originally Posted by flightdoc

I think it's similar to the sound of the old diesels under heavy acceleration from the stop.

Good analogy.

I'd describe it as a "chatter behind the clatter". Clatter being the normal engine operating noises, and the chatter being the pinging.

[bobzinger]

wooden balls knocking around in a plastic bucket.

[cyclecat]

Seriously? You guys are serious? The noise is that bad? I guess that's why I have no clue what pinging is, I've never heard it.

[cactusjack]

When I hear it, it send chills up my spine.

[flightdoc]

cyclecat, I can't imagine you've never heard it before. You probably just didn't know what you were hearing.

vin

[cyclecat]

Never heard anything like that on either of our Nomads and I ride both. Every couple of months I take Brian's for a ride just to hear if there are any new or strange noises, he has only 20% of his hearing and has had since he was 8, so he can't hear the weird noises in the engine.

Vin - we went for a 400 mile ride yesterday, I checked the forum for replies along the way, and then was listening for this particular noise. Nothing, nada, our Nomads do not do that even under acceleration. I'm sure after riding one Nomad off and on for for 9 years, and one steadily for 7 years, if they pinged, I would have heard it by now. Maybe it's got to do with the altitude here, the fact that we run nothing but premium gas and really good oil, and have done so since the Nomads were new.

I can honestly say I have never heard a noise anything like that on either Nomad.

[macmac]

Alt creates less air, and while the bike should adjust for less air, it will tend to ne a richer fuel mix over all. This explains a lot.

About what is you alt?

[cyclecat]

At home, we are at 3156 feet and the highest point we hit was 4700 feet according to the GPS.

[AlabamaNomadRider]

I'm with you CycleCat as mine has never pinged. I live at an altitude of 1500 feet which isn't all that high but higher than sea level. I have 9500 miles on the Nomad and it has never pinged. I do know what it would sound like also. I have had cars that pinged but when I put in a higher octane gas the pinging went away. One reason I run at least 89 octane in the Nomad at all times. Did run a tank of 87 octane and got the worse gas mileage I have gotten. Switched back to 89 on the next fillup.

[nomadbehappy]

I havent heard the pinging sound (at least I dont think so), but when I shut it off I hear what I would describe as a "ticking" sound, is this the pinging?

[snarleybill08]

the standard description for pinging is like the sound of pieces of glass being crushed. it is caused because the flame front travels to fast and causes explosive impact on the metal parts. the metallic sound you here is the hot gasses hitting the piston and cyl. head surface with a hammer like force. higher octane fuel has an additive that slows the burn rate down. preignition is usually caused by a hot spot in the combustion chamber like carbon or an overheated electrode on the plug, that causes the mixture to ignite to early. it usually sounds like a deeper metalic rattle. either one can cause damage to the engine. or can combine to cause damage.