Re: Tom's grinning

[Steve Stegmann <stegmann@domain.elided>]

Tom, John,

I've seen some oil fouling.  Oil leaves a black deposit which will be 
coked, thick and cratered like a cinder, or black and wet/greasy.  My 
personal record is 14 quarts of straight 40w in one day on a tractor.  We 
had to clean the plugs every half hour or so.  Anytime you came off full 
throttle it would foul.  It looks like the black char that you find on an 
old cast iron frying pan.  Hard, brittle, thick.

Excess fuel will also leave a black deposit but it will be a black powder. 
Some of it will rub off on your fingers like the deposit in the tailpipe,
(same stuff).  Even if there's a lot of it, it won't be as thick as the
oil deposit which can get 1/16" thick. 

Probably you're going to find some combination of both.  How much oil 
does it burn.  

I wouldn't even look at the valve guides if the compression is good.  If
anything is wrong with the valves, it won't hold compression.  If the 
valve guides leak a major amount, the guides will probably be loose and 
the valves won't hold compression.

Take out all the plugs and put them in proper position on a board and see 
how they all look.  What is the color and consistency of the deposits.  
Both on the metal portion and on the ceramic insulator.

Steve
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Steven A. Stegmann
     _/_/_/    _/      _/_/_/ "No free man shall ever be debarred the use
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   _/        _/ _/   _/        people to retain the right to keep and bear
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 _/    _/ _/    _/ _/    _/    
 _/_/_/  _/     _/ _/_/_/         Thomas Jefferson, June 1776
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