The local Alfa mechanic always cracks all the spark plugs one turn out and
starts the car to blow out the carbon. I never do, but I probably change /
check my spark plugs more often than Alfa owners who do not do their own
work. So I probably have less carbon build up.
The theory is to crack the
carbon, but not enough for it to fall on any open valves. Then starting the
engine breaks it out from around the spark plug and blows it out the exhaust.
I would think you could look down the spark plug hole and see if the valves
were open and then blow that cylinder out with an air hose. But a chunk of
carbon could still come to rest on an open valve. Then when you turn the
engine, it smashes and makes a gap that can later allow flame to pass that
area and burn the valve.
By starting the engine, you have intake air or
exhaust passing over the valve as it closes.
Hell, I dunno. I guess that
is why I never bother.
Ciao,
Russ Neely
________________________________
From: Brian Shorey <[email protected]>
To: Shawn Mayer
<[email protected]>; [email protected]
Sent: Sun, January 31,
2010 8:09:58 PM
Subject: Re: [alfa] Spark plug changes
I've never read such a
thing, and I'm not sure I follow the logic. What difference would it make if
you knock off some carbon and blow it out the exhaust ports with your old set
of plugs vs a new set of plugs?
??
bs
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