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Re: educational question re sparks, compression, and power

To: "MG List" <mgs@autox.team.net>
Subject: Re: educational question re sparks, compression, and power
From: Max Heim <mvheim@studiolimage.com>
Date: Mon, 26 Jul 1999 18:41:15 -0700
Paul Hunt had this to say:

>>if the spark plugs are loose, is compression reduced?   I would think so if
>>pressure is lost around the plug.
>
>Unlikely to be significant, I would have thought.
>
Yeah, I was doing a tune up the other day and forgot the plugs were only 
in finger-tight (actually, less than that). I fired it up to set the 
timing and didn't notice any running problems. Only noticed it when I 
pulled the leads to access the distributor hold down bolts. Probably the 
compression leakdown is too slow to make any difference at engine speeds 
(i.e. something like 1/10th of a second at idle).

But then again, my wife's Honda 2-cylinder once blew a plug clean out. 
Cross-threaded in the aluminum head, apparently. So I wouldn't recommend 
running with 'em loose as a regular thing...



--

Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the red one with the silver bootlid.


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