Re: [Amc-list] 195.6 Photo Page
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Re: [Amc-list] 195.6 Photo Page

Yep, typical 196 block! You missed one important pic though, the crankshaft flange! Since you mention it, and few have seen it, I hope you go back out and take/add a pic of it. 

You have the start of a good 196 OHV page, just needs a few specs and a mention about how to maintain that cylinder head. I'll write something up on that if you like. 

There's only one visible difference in later (mid 63-65) blocks. That's the extra hole roughly above the front oil tap into the main oil gallery (the bulge on the oil pump side that runs the length of the block through the pump) in the flat of the block -- it taps into the first cam bearing journal. The only other difference I know of is internal -- the diameter of the cam bearings changed in model year 1961, and the bearing itself changed in mid year 63 to accommodate the new head oiling. 

The parts book says the bearing diameter changed beginning with L-head engine code 20830 and OHV code 20908. When no engine type/size letter is given the code reads the same, just omitting the letter. In the cases above 2 is 1960, 9 is September, and 08 is the eighth day (of Sept.; 30 is of course the 30th -- AMC started building 61 models in late July/early August of 1960, so some early 61s will have the old style). I believe the diameter change was due to a design change necessary for the aluminum engine since it coincides with that engine's introduction, but I have no proof. The same cam bearings are used for all three L-head engines though. 

The change in the bearing in 63 was simply adding an oil hole to align with the head oiling line in the block. The cam bearings changed for all 61-65 models, if the hole isn't needed it does no harm as the block blocks it off. If 61-63 bearings without the hole are used it's a simple matter to drill the hole before inserting the cam. I'd install the bearing then drill the hole, and dress up the inside edge with a fine round file or fine sand paper/emery cloth. 

It's possible that 63-65 196 engines were cast slightly thinner than older ones, at least the cylinder walls. I have no idea if they were or not, I've never compared the weight of early and late blocks. I do know that thin wall casting techniques appeared around that time though. For the most part manufacturers stayed with the older cores and techniques until an engine design was replaced, but Chevy altered their small block cores to take advantage of the new casting techniques by thinning the cylinder walls (and other areas?). AMC may have done the same with the 196 and GEN-1 V-8, I can't say for sure. I'd check before doing any drastic overbores (more than 0.060"). Early 287 blocks can supposedly be bored out to 327 size (0.250"!!), but I wouldn't try it with a 64-66 version without checking wall thickness first. I know for a fact that pre 63 196 blocks can be bored up to 0.125", but finding pistons is another story! I once knew a fellow who bored an L-head that far (it was
  actually 0.123" or 0.133", or some odd number like that), but it uses flat-top pistons. I don't recall what pistons he used, but I'm pretty sure they weren't custom, that's why the odd bore. 

Date: Thu, 13 Nov 2008 14:30:49 -0800
From: Tom Jennings <tomj@xxxxxxx>

Joe Fulton wrote:

> > Tom,
> > 
> > Put a picture of the 1958 block up on the web or send me one.  I'd like to compare it to several engines I have around here, which are all 1963 through 1965 blocks I think.

Here 'tis. Scroll down past the crap text to see the photos. Not 
labelled yet, it's all a placeholder page.

Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
(free download available!)

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