Jay,
I just found out that there was a service bulletin issued in 1969 about 
rough idle and/or surging on six cylinders. The fix was new intake 
manifold gaskets and a specific intake torque sequence. The bad part about 
this fix is that you need to separate the intake and exhaust manifolds and 
there's a good chance that one of those studs or bolts will break.
The torque sequence starts with the top left bolt behind the carburetor 
and works clockwise outward. After that, it calls for tightening the nuts 
on the intake to exhaust manifold studs (left first, then right) between 
the carburetor and motor and then the outer manifold bolts (the ones that 
are on the bottom) in the same order.
The vibration could be a bunch of things. Once you fix the wheel bearings, 
try over-inflating the tires (add bout 10 psi) and see if it changes or 
goes away. You could also have any of the following out of balance or 
damaged: wheels and tires, drums, driveshaft. Also, worn out u-joints or 
rear wheel bearings can cause vibration.
Matt
At 11:35 AM 11/7/2004 -0500, you wrote:
I finally got around to tightening the intake and exhaust manifolds to 25 
ft/lbs and it did help the vibration problem but not entirely.  I also 
have a synchronous vibration while driving at about 35 mph. If I let up on 
the gas it diminishes slightly . There is a  "flex" fan on the engine, 
seems to be in good condition and the water pump has no play in the shaft. 
I would like to find a 5 blade OEM  fan as i don't like flex fans much. 
The problem with that is it is a small fan because of hose clearance 
problems. You have an American, so you know what I mean. The  35 mph 
bibration may be a wheel bearing going bad. When I got the car back in 
April, I was checking things over and found the LF wheel was NOT tightened 
down properly at the wheel shaft nut. I tightened the nut about a 1/4 turn 
until I had no play in the wheel when held at the top and bottom.  I have 
no idea how many miles the bearing was loose and driven that way. I am 
going to replace the bearings on the front wheels just to be safe.    BTW, 
I had a simliar  35 mph vibration on my 66 AMBO and I never did find out 
what caused it. the only thing i didn' t replace on it was the engine 
mounts. I have replaced the tranny mount on the American.
Jay
----- Original Message ----- From: "Matt Haas" <mhaas@xxxxxxx>
To: <mail@xxxxxxxxxxxx>
Sent: Monday, November 01, 2004 8:54 PM
Subject: Re: engine vibration 232 engine
Jay,
Check the intake manifold bolts. My American did that and tightening the 
bolts solved the problem.
Matt
At 06:12 PM 10/31/2004 -0500, you wrote:
Hey Guys, i have a 66 American with the 232/2bbl engine. I have set the 
timing, set the idle speed at 700 rpm in neutral/ 550 in drive. The 
engine has new plugs and points, doesn't appear to have any vacuum 
leaks.  At the 550 rpm speed the engine has a rapid vibration which is 
quite annoying. The vibration mostly stops when i speed the engine up 
above the idle.  I have replaced the tranny mount which was dissolved 
from tranny fluid getting on it before i got the car. Could the engine 
mounts be so old and stiff that they won't absorb even the slightest 
vibration and transmit it to the frame? I had a 65 American with a 
232/2bbl when it was new in 65 and i don;t remember it being anything 
but smooth idling. The engine runs smoothly as far a vacuum gauge shows, 
no fluctuations due to worn valves or rings. The engine doesn't smoke 
and has 120k miles on the odometer. Someone did put the oil kit from the 
side of the block up into the valve cover as suggested in a service 
bulletin. I know that has nothing to do with the idle. Just mentioning 
it as I hadn't seen this done to many 232 engines.  I didn;t mention it 
but the engine has new plug wires also. Any ideas?
Jay in Central FL.
mhaas@xxxxxxx
Cincinnati, OH
http://www.mattsoldcars.com
1966 Rambler Rebel
1968 Rambler American sedan
===============================================================
According to a February survey of Internet holdouts released by
UCLA's Center for Communication Policy, people cite
not having a computer as the No. 1 reason they won't go online.
mhaas@xxxxxxx
Cincinnati, OH
http://www.mattsoldcars.com
1966 Rambler Rebel
1968 Rambler American sedan
===============================================================
According to a February survey of Internet holdouts released by
UCLA's Center for Communication Policy, people cite
not having a computer as the No. 1 reason they won't go online.