<VV> detonation

[djtcz at comcast.net]

----- Original Message ----- 

From: "J R Read" <hmlinc at sbcglobal.net> 
Subject: Re: <VV> Don't let this happen to you 
To: <virtualvairs at corvair.org>, "Matt Nall" <patiomatt at aol.com> 

Matt, 

I've seen holes through the top before from detonation. This is the first 
one I've seen through the side. 

Are you telling me that (hole in the side) this is a common result of 
detonation? 

We blamed it on overheat on the bottom side of the cylinder. 

Later, JR 


=============================================== 
Abnormal combustion can take many forms. Multiple types can coexist or feed each other, and cause a variety of symptoms depending on severity. 


Detonation can be caused by a batch of different things, but it is a phenomenon than occurs in the "end gases" off in the furthest nether regions of the combustion chamber that are last to combust. 
That usually ends up being on the edge of a piston somewhere. Some tuners call the early stages "the eats" because of the material lost from the piston. 


http://www.thor-racing.co.uk/images/piston_detonation.jpg 


When aluminum is being progressively torn from the piston by detonation it is often apparent as speckles or tiny balls on the spark plug. 
This is a relatively mild case, but not to be ignored. 
http://image.carcraft.com/f/9638748/116_0703_07_z+spark_plug_guide+detonation.jpg 


Severe Detonation's shock waves can even break stuff like plug insulators and hypereutectic pistons' ring lands, head gaskets, and crankshafts.