Andrew Mace writes:
> 1964 Spitfire
Is this the white Spit?
> I immediately saw the cracks in the top piston ring, which fell to
> pieces as I finished removing the piston.
Not unusual. Time for at least new rings all around.
> Only one thing was strange: I have yet to find any evidence of the middle
> ring! ... Does anyone have any good ideas as to
> 2. why it would not have been used when the engine was last assembled
I can think of a couple possibilities- but you won't know for sure until you
pull all the pistons.
One obvious answer would be that someone broke one of the rings, but put
it together anyhow. Hey- it works, right?
Another possibility, is a build decision. The second ring is to help hold
compression & reduce blowby. If you carefully size the top ring so that is
seals just right when hot, you won't need it as much. Each ring you
install increases the friction caused by the piston movement, so leaving
out a set of rings could reduce friction, and *possibly* gain some power,
if not offset by compression losses. The problem here, is that gains made
by reducing compression losses are very important to producing power.
I can't beleive how many people run race engines with *NO* air filters.
This is one area that the "vintage way" is the wrong way. The wear in the
cylinders due to any dust sucked in very quickly results in enough power
loss more than surpass any power gained by not sucking through an air
filter. Not to mention what happens if you suck in something bigger, or
get a big load of dust or sand kicked up by another car!
________
/___ _ \ Roger Garnett (Roger-Garnett@cornell.edu)
/| || \ \ Agricultural Economics | The Wayward Sports Car Centre
| |___|| _ | 3 Warren Hall | http://www.wayward.team.net/
| | \ | | | Cornell University |
\| \ |__/ / Ithaca, N.Y. 14853-7801 | (607) 533-7735
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