hi compressions: wasDIY_EFI Digest V1 #258

[John Faubion]

> I have read that the big reason for four valves is to get the spark 
> right in the center.  Flame front has much shorter distance to travel, 
> meaning higher compression without detonation.  You could probably get 
> the same effect with four spark plugs per cyl.   BTW, I believe 

Actually the big reason for multivalve chambers is more area is exposed
around the valve to flow fuel. Two small valves have much more flow
capacity than 1 large valve but is more expensive that manufacture.

> detonation is what happens after spark but the mix explodes before the 
> flame can travel far enough to get the whole mix burning.  Pre-ignition 
> is another phenomenon in which hot parts or diesel effect ignite the 
> mix before spark.
> That's as I understand it.  Comments?

True.

John Faubion
jfaubion at beaches.net