Message text written by Allen Nugent
>If in doubt, you should measure the clearance of your pistons at TDC, and
>the valves. You can do using the old head gasket - just don't give it
quite
>as much torque as normal. Oil the tops of the pistons and bottoms of the
>valves, and put plasticene on top of the pistons (under the valves). Turn
>the engine over once by hand, take off the head, and carefully peel off
the
>plasticene and measure the thicknesses. This will tell you how much you
can
>skim off the head and how much extra valve lift you can run (if you're
>considering a cam grind). At this point, you can also calculate your
>compression ratio (after measuring the volume of the combustion chambers).
<
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Allen, that sounds like a good method to do the measurement. I'd just
have to find the stock spec of valve-piston clearance. Do you have
any idea what that should be?
I like the plasticene idea. That reminds me of a (fanciful) story
about Thomas Edison in his later years. As you probably remember,
he was mostly self-educated. He was interviewing a new employee.
This was a new engineering grad. He asked the engineer to tell him
the interior volume of one of this lightbulbs. The engnieer made
all sorts of measurements, appoximations of wall thickness, etc, and
presented his answer the next day after an all-night project. Edison
looked at the multi-page dissertation, said that it looked good. He then
took the bulb, broke off the vacuum seal tip while under water, and
let water get sucked in. He then took it out, dried it off and decanted
the
water and measured it, and decided that the engineer was off only
by 15%.
I will try to measure the head thickness around the edge hear and there.
If that seems to give screwy results I might try the plasticene
Where does one get uprated springs? I have seen only those for sale
at the big 3, and these appear to be stock.
-Tony
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