Re: [Amc-list] 196 pistons

[Tom Jennings <tomj@xxxxxxx>]

d stohler wrote:

> so, i was wondering, if i rebuild this engine, whats wrong with going with some more common, easier to get flat top pistons, and shave the head down to close up the chamber, and have small reliefs in the pistons to clear the valves. maybe put in some rods that are easier to get ahold of that can be machined to fit? 

If that would work, a lot of people would be happy.

But it seems like a deep wedgey-double-hump to flatten out. This was 
partly the reason I wanted to saw up one of these heads. Now I really 
want to do that; I wonder if Bruce has one...

The hump in the piston can't be removed; the casting follows the shape, 
it's not simply a lump on top. It's about 1/2" high.

With a flat top piston, the compression would plummet to nothing. It's 
already low. Even if you lopped 1/4" off the head (ouch) I wonder if it 
would make up the difference in compression that lump makes.

The combustion chamber in the head is VERY deep, like 3/4" near the 
plug, down to 3/16" or so at the thin edge of the wedge. There's a shelf 
at the thin end.

Photos of the whole thing are here

http://wps.com/AMC/1963-Rambler-American/Combustion-chamber/

There's only .37" of valve lift! Should be easy enough to avoid whacking 
the piston.
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