Running Bad HELP!

[nailr65]

So this year when the weather got good it was time to fire up the car.  I have a 65 vert. 4 speed. with the 401.  The car started and idled just as expected.  After it warmed up, I took the car for a ride and it ran very rough, (fuel was treated for the down time during the winter).  I thought I was having carburetor issues and took the Carter AFB off for a rebuild (long story here, so I'll fast forward some).  I kind gent from this site was generous enough to donate a carb to get me going again(Carter AFB).  I put that carb on and it idled better but when I put the gas down it ran very rough in the secondaries..  I checked the timing and it tends to run best at 15 ATDC, which is a lot compared to the original specs.  (new plugs, new wires, new cap, Petronix under distributor, new coil, no vacuum leaks.)  I was told the car sounded like it had a different cam in it as if the motor was built up.  I have no idea what the inner workings are in the engine.  Any advice is welcome.  Thank you in advance.

Dave

[red65gs]

Hello,

Has the engine been rebuilt or the distributor been out? If the engine is original, they used a nylon toothed gear for the timing. That gear can wear/break and change timing after some years/miles. If your distributor has been removed (like to install the pertronix), it's possible that the reinstall was off. You may have to check the #1 piston and see if it is fully extended at top of compression stroke when balancer mark is on zero. At that point your rotor should be pointing at the #1 spark plug wire.

[TrunkMonkey]

Stale gas, especially the stuff that has moonshine in it is very bad for nailhead valve stems and can result in sticking valves, bent pushrods and mechanical damage from piston and valves making contact. (from varnishing) And the bad gas can just make an engine run very crappy overall.

And varnish from stale gas gumming up a carb, ethanol swelling rubber seals and o-rings, etc. and corrosion from water being absorbed in the ethanol and concentration after the fuel evaporation.

Even treating fuel, the ethonal gas can still turn to garbage over time.
 
Another thing is the exhaust flapper in the passenger side sticking and causing exhaust restriction and excessive heating on the right bank and/or carb heat soaking.


Since the car has sat, that is the very first thing I would look at. (full inspection of fuel delivery system).

And then looking at things like electrical connections, grounds and such.

If the car was running fine when parked, and started OK, unlikely anything mechanical has failed that would not leave you with a no start or very unhappy engine.

[GS66]

Can you get non-ethanol premium where you live in NY? Makes a huge difference in my cars. You might try a can of Sea Foam in the tank too, might help you burn through the old gas if that turns out to be the problem. Good luck.

[option B9]

  Our Nailhead motors also have a casting plug on the underside of the intake manifold. IF that plug is rusted to a point where it is leaking air the 401 will run very rough because now you have a vacuum leak. This is a very inexpensive part that can cost you a lot of unnecessary repairs.
   The part is called an expansion plug 2" Dorman part # 550028 about $1 each.

   Tony 

[GS66]

You might be able to tell if the plug is leaking by spraying carb cleaner at it while the engine is running.

[nailr65]

I'd like to thank everyone for their input.  This site is such a great tool to help us work through trouble shooting.  Update.  I replaced the plugs and the car runs awesome.  I didn't expect it would be the plugs because they were only a couple years old with very few miles on them.  Running a bit rich I guess.  Thank you all again