Re: [Amc-list] motor motion

[Frank Swygert <farna@xxxxxxx>]

You need to check the bores PERPENDICULAR to the wrist pin for wear. The 196 usually wears "crosswise" (to the block) near the bottom of the bore due to the side-to-side action of the long stroke. Not really bottom of bore, but where the piston is when the crank is at max sideways pull/push position. I've had a couple that barely had any ridge at all, but needed 0.020" to be right. For some reason 0.040" pistons seem to be common -- I've got two brand new sets, one for an OHV and one for an L-head. Most I've found have been 0.040", most common for most other engines is 0.030". I guess machinists figure since it can be bored 0.080" or more why not get what you can if it needs boring. 

Good call on the heads! I wouldn't use an unknown 196 head without checking it for cracks. Since the spot is on a corner I wouldn't assume a cracked head. Every one I've had that cracked did so around one or more exhaust valves. Which is funny in a way -- they usually blow the head gasket as they are running hot when the head hasn't been retorqued. Most people don't notice anything until there's steam coming out, by which time it most likely has warped a bit and if run hot enough (or it's the 2nd-5th time it's been done) cracked. Could be warped a little, but even that seems strange for a corner. 

---------------
Date: Mon, 12 Jan 2009 18:27:39 -0800
From: Tom Jennings <tomj@xxxxxxx>

All of the bores were 3.185" (parallel with the wrist pin).

So I have two heads to take the local shop for boilout and crack check. 
Won't have any further work done to them now. I wanna stack up parts for 
the engine build and decide exactly what it is I'm gonna build.

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)

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