[Amc-list] Off we go!

[Tom Jennings <tomj@xxxxxxx>]

The Rambler's getting loaded up today for the trek to Black Rock City (aka 
Burning Man). This year we gotta small utility trailer, don't worry, I'm 
watching the weight. Maybe that '55 Nash won't be there and I'll have the 
oldest passenger car there (some 40K people attend).

I put the auxillary fuel tank back on the roof, it's a bit embarrassing, not 
to mention illegal and reduced safety, but it gives me 500 mile range, and 
since this is a Sunday drive out through sparsely populated desert (LP gas 
hard to find Sundays after 5pm!) will be a huge help.


I JUST got the ignition timing straightened out today; put the vacuum advance 
on after having it off to get the mechanical down.

This is a 232, LP only, 9.5:1 or so in front of an M11 BW auto, in a Classic 
wagon, 3.31 axle and 27" tires.

 * 30 degrees (not a typo) mechanical advance in at 2100 or so
* 4 degrees static
* 17 degrees vacuum advance (shimmed down unit)
* manifold vacuum

Sweet setup, as it cranks fast with very little advance (4 static, cranking 
vacuum) but runs cool at idle. No pinging until coolant temp gets towards 
hot.


I've had an increasing problem getting the idle mixture right with this carb 
going on 17 years, a IMPCO CA-125. Very tweaky, had to fiddle PCVs to get it 
right... it's been getting worse, with #1 cyl not contributing much at idle.

Hadn't done a compression check in a few years, so I did one this AM after 20 
highway miles hot; bad news...

Only checked #1, #2, and #4. 1 and 2 were 100 psi and #4 105 psi. In the late 
1990's they were all around 140 - 145. I'll do them all later (in a hurry to 
pack today) but no reason to think the others are wildly good or bad, so it 
sounds like 210K miles and 19 years on this rebuild [about 300K total on 
this '70 motor] is the problem, probably plain old ring wear. Very little oil 
blowby, only slight smog out the filler if I pinch off the PCV. I'll probably 
use a quart of oil this trip, about 1100 miles round trip.

Runs good and smooth on the highway, but I've been unable to get the mileage 
up to past numbers (13 - 14 mpg LPG equiv to 18 - 20 mpg gasoline via BTU 
calc; it's around 11.5 now) no matter what, and the recent massive ignition 
timing improvement and TFI upgrade should have it up there.

Can't complain I guess, and assuming the little American works out, I'll still 
have a backup car for the Hornet. (All AMC here, no "late model" crap, though 
the '70 Hornet has enough plastic for me to consider it 'late model'.) 

Maybe it's all in the head instead, that would be nice, but I suspect it's 
mainly rings. It will be very interesting to tear this thing down since it's 
been LPG-only and Mobil One only since built in '88. (I especially wanna see 
the crank; I was incredibly lucky, the crank journals were so good when I 
rebuilt it that the machinist just crocus-clothed them, he said they were 
perfect, round, and all concentric, so it has 0-under bearings.)

Off we go tomorrow anyways, and will come back very dusty.
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