[Amc-list] little american stuff

[Tom Jennings <tomj@xxxxxxx>]

Did a bunch of driving today, all ran fine with one and a half
problems. I took it one exit's worth of local freeway, it's a
bit scary with the worn-out front end, so I probably won't be
commuting in it until I get that all fixed.

I can't find the damn timing marks on the front pulley, so I
think the distributor is installed wrong, but I timed it by
hand and it's pretty close.

Brakes are fine now, I haven't stress-tested them yet, but
I suspect 9x2's are not such a good idea on 21st-century LA
freeways.

The gearing and axle is a little odd. 3.77:1 is a big ratio
for the street, and I found myself driving it like a two speed
in town, though I did get the hang of double-clutching and
rev-matching to get to first for climbing a twisty super-steep
one lane hill. Clutch feels fine but I imagine it's at
end-of-life like everything else.

Second has a little scritch in it, so the dogs are probably
worn but eh, I've driven worse, it'll last. This isn't a car
you speed-shift anyhoo.



The half-problem is that the NOS Carter WCD carb which Joe kindly
provided, I just bolted it on without even looking at it (OK,
I *looked* at it so that I bolted it on the right way 'round),
turns out to have a flat spot, right off idle, before the main
circuit picks up, so it bogs dead right when you are taking
off from a stop. Press lightly, bog and will stall; press
further it picks right up. I don't think it's just squirter
adjustment. It's very "sharp" and predictable. Everything else
is close to perfect, choke, idle, power, etc.

Anyone have any 'typical problem' insight into this little
off-idle bog with a WCD? I'm really lazy! :-)



The other 1.0 problem is after running around, then parking
for two hours (engine cold) it dropped a pushrod a few minutes
into driving!!! Didn't bend it, it just fell out. I really had
the valves adjusted right!

The motor was cold, when valve lash will be maximum, and I didn't
rev it beyond 3000, or at worst 3500 I suppose is possible. But
I can't believe Nash would design a motor where pushrods fall
out when cold under any reasonable driving condition. "Cold"
here is 75 today!

The pocket on the rocker (adjuster) is deep, but the tapped
dimple is shallow, and these are loooong rods, and get
rattley-loose when the motor is cold. As it heats up to operating
temp they tighten right up to adjusted spec. (12 though intake
hot, 16 thou exhaust hot).

That really annoys me. It was #3 intake. I can't see how it
happened.  The valves are NOT! tight. I hand-operated every
one on the bench.

I'd like to believe it's a one-time thing, the head was just
installed, torqued and adjusted, first drive out, but I'm fooling
myself. There's got to be some problem in there.  The rocker
shaft is worn, there's excessive oil flow, but it's not THAT bad,
and I know I assembled it right.

I will re-check torque on the rocker shaft, but that seems
like a religous act more than a serious diagnostic. I really
really checked for straightness that one that fell out, it's
as perfect as I can see against my Starett 18" straight edge.

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