Possible knock damage

[quixotic]

I installed a Boyer electronic ignition, but it gave me some serious knock (and I only ever use premium with zero percent ethanol).  What would be the best way to check for possible damage?

Thanks in advance.

[nhmaf]

Probably no problem if you didn't run it for long in that state.   Sounds like it was much too far advanced.

[Barry]

Pinging, more properly called detonation doesn't usually cause any immediate damage. It normally has to be severe and prolonged to be an issue.

You could take a peak at the piston top through the spark plug hole to see if there is any pitting also look carefully at the spark plug to see if there are any tiny spheres of vaporized aluminium.

The thing that wrecks engines is pre-ignition which is entirely different being triggered by hot spots and not the ignition system. Easy way to distinguish between the 2 phenomena is to remember that pinging occurs some time after the spark has initiated the burn and pre-ignition occurs quite some time before the spark so it has much longer to build pressure while the piston is still on the way up hence the destructive effects.

[Ed Miller]

I think you have detonation and pre-ignition mixed up:

http://klemmvintage.com/camerondeto.htm

[Barry]

I think you have detonation and pre-ignition mixed up:

No, I don't think so. The article goes into much more detail about the damage that detonation can do particularly when it occurs at high revs when it's less easily detected but detonation in airheads at the usual 2500-3000 rpm is very easily noticed and avoided by rolling off the throttle. I get the impression the article is talking about racing so detonation damage is going to be far more severe. I could have panicked Quixotic by saying that severe detonation can cause significant damage but I never heard of that in an airhead. That doesn't mean I got things mixed up as the article makes the same distinction between detonation and pre-ignition as I did. Detonation occurs after the spark and pre-ignition (the title sort of gives it away) occurs before the spark.

"detonation is not the same as preignition. Preignition is lighting of the charge before the spark , by some hot object in the combustion chamber usually the overheated center wire of a spark plug whose heat range was too hot for the application"

"Detonation, by contrast, is self ignition of some of the last parts of the charge to burn  the so-called "end gas" out at the edges of the combustion chamber after the spark has already ignited and mostly burned the charge" 

[livingdeadhead]

ride it, if it runs ok its ok, it it don't , its broke.....then worry

[Ed Miller]

Ah.  I thought the pinging was pre-ignition, not detonation.