Re: [AMC-list] Some Days are Diamonds and...

[Frank Swygert <farna@xxxxxxx>]

I've run mine up to a couple years between re-torques, somewhere around 10-15K (I typically put 7K a year on my little American for 6-7 out of the 14 years I drove it). The L-head doesn't seem to have a problem, especially not once a modern head gasket (anything made from about the mid 70s up). I know people who have them and don't think the head has ever been off, and haven't been re-torqued to their knowledge of many years and 10s of thousands of miles. Could very well be the area under the bolts, or the width of the sealing areas. The L-head block has a lot more of both, though some of the sealing surfaces aren't any bigger around the cylinders. Could be the aluminum intake under the head bolts on the left side too. Aluminum expands and contracts more than iron and steel, and could easily be the culprit. Anyone want to make a steel plate intake and run their 196 2-3 years /over 15K miles and see if the head gasket blows? I didn't think so... ;> 

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Date: Sun, 31 May 2009 15:37:04 -0700
From: tom jennings <tomj@xxxxxxx>

I forgot: I still wonder at the reason for needing to retorque this head.
This time, I used the torque wrench to see how much force was needed to
crack them loose before retorque.

It's hard to tell, due to sticktion etc, but most seemed to need 70 - 80
f/lbs to crack loose (CRACK of sticktion sound) but a couple took a bit less
than 60, without the CRACK sound. All have proper thick, hard washers, oiled
right on assembly, etc.

The bolts and washers on iron were the most consistent; the ones along the
aluminum trough cover felt ever so slightly "funny" typical of aluminum.
Perfectly normal there, just less feelable.

So who knows. I don't thnk the "loose" ones were loose, just that the
head/washer didn't sticktion to the head. Maybe that's the source of the
unknown, unspecified 'must retorque'. The under-head area is small, there
small pattern 5/8" heads.

I just now realized that I should have prick-punched them to see oif they
rotate. I imagine that all head bolts have a twist in them after torquing,
and I just have no idea how bolts behave under these conditions.

I know Frank is right, that once a year is all they need. But I'm doing them
twice, spring and fall, simply because it's a 15 minute job once you have
the valve cover off to tweak the valves. I like to keep my engines at 100%
top state of tune 100% of the time (fends of problems, and gives me slack
when I can't get to fiddle them like during this last quarter of school).

--
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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