Hi All,
I've been having some problems getting the 361 motor in my '59 DeSoto
Firesweep Seville started.
BJ Pultanovich came up to help me out today, and now I've got him
totally stumped as well. By all means that we can determine, the engine
SHOULD fire. The problem is it just doesn't.
To give some background, I had replaced the points, plugs, condensor,
cap, coil, and rotor, and was satisfied I'm getting a good spark. The
compression had been pretty low (around 60 PSI on all cylinders, but
after two weeks of soaking in Marvel Mystery Oil, compression jumped to
around 90-110 on all cylinders. To test for bad rings, I dumped about a
quarter quart of ATF down the carb throat, and the compression jumped up
to around 160-180 PSI on the cylinders I checked. The engine is pretty
gooey... so I'm guessing that sludgy rings are causing the low
compression. A test of the #6 cylinder revealed 50 PSI on cranking, but
with all the other plugs in, and with a closed throttle and choke.
The previous owner assured me it had been running fine when parked, and
I have no reason to doubt him. In fact, the last inspection sticker
(Oct. 1973) shows that the car had 48,982 miles when inspected, and the
clock only shows an additional 13 miles at 48,995 now.
A lot of people suggested that the old fuel was bad, and/or carb
problems. Actually, the old fuel was pretty bad (it was pumped when
Nixon was in office) but that's not the problem. The car, at present,
is pumping from a gas can full of fresh clean fuel. The gas tank is not
even on the car. The fuel pump is functioning correctly, and the carb
is getting plenty of fuel. Both carb and pump were just rebuilt. Tried
dribbling gas down the carb throat too. But let's eliminate fuel
completely from the scenario -- by using plenty of ether starting fluid.
Still, the car won't "kick over" and fire.
To remove the exhaust from the equation, I disconnected the muffler.
The heat riser is free, and I have verified that air is coming out of
the open exhaust pretty freely and regularly.
So that leaves two major possibilites, first that there is something
still wrong with the ignition, and second is that the compression is too
low.
We tried replacing points, plugs, condensor, cap, coil (including a
brand new super-coil), and rotor, and even tried replacing the points
cam from a spare distributor. We rearranged the spark plug wires to
every possible combination. When arranged in such a way as that the
timing is advanced by one or two terminals, the car will kick back a bit
on each cylinder. Eight kicks per revolution -- but it's so far
advanced that it stalls the cranking a bit. One would think then, that
the wires are in the correct order, there is a spark with each
cylinder's compression stroke, and the distributor is indeed firing.
There is much blow-by coming out of the valve covers when the engine
kicks in this fashion. Little smokes comes from the exhaust.
Rotating the distributor back to the 'correct' position yields nothing.
You would think it would at least chug a little and help the motor turn
over. That is, unless the power produced by each stroke is
substantially less than the starter's torque in the forward direction.
A few others have suggested towing the vehicle up to around 35 MPH while
in D or 2 range, where the trans will actually turn the engine over....
basically, the old push-start. That's appealing to me, but it would be
a bit difficult in my current scenario. The car is in a garage in a
city neighborhood with narrow streets. It's a long, flat, dead-end
street, but there isn't much wiggle room if the car was to buck or
lurch, so I'm going to have to count that one out in my situation, but
it sounds like a good idea for others who are facing the same problem --
if you live in the country.
Another good-sounding approach was to disconnect the starter cable at
the relay, and hook up another battery in series to give a 24volt crank
for short periods of time. (12 volts to the car, but 24 to the starter
-- connecting the starter relay to - on a second battery and + directly
to the starter cable. If you draw it out, you'll see what I mean) We
tried that too. no luck. It turned over faster, yes, but still would
not fire up.
Now that leaves only the compression as the culprit, by my logic.
Should 90-110 PSI be enough to start the car? Anyone who has been down
the same road, what is the lowest compression you've seen a car start
with?
Connecting a engine-top-grounded spark plug outside the engine, directly
to the coil gave 8 very good blue sparks per rev. Connecting the same
plug to the distributor #1 lead gave one good (but somewhat weaker) blue
spark per rev. Previously, when I had verified this with a timing
light, I was able to see that it was firing at the correct time.
Other notes:
- Continuously checking the plugs revealed no carbon, oil, or wetness.
- We're sure it's not 180-out as we checked for TDC by compression and
verified it to the timing mark. We even verified that the #8 cylinder
was compressing when it should on the cap.
- We bypassed the ballast resistor. We replaced the ballast resistor.
We jumpered the ballast resistor.
- Disassembled the distributor. Breaker plate is free. Shaft is free
with very little play. Weights are free. Vac. advance is working.
- The engine has never been disassembled.
- Connecting the coil directly to the #1 cylinder (thus 8 cranks per
rev) yielded one through-the-carb backfire per rev.
- BJ brought an inferno-on-wheels kerosene heater that had the garage
cranked up to around 85 degrees -- so warm in fact that the engine was
no longer cold to the touch. But it doesn't start at 15, 35, 50, or 70
degrees either.
- Engine rotation on cranking: clockwise. Distributor rotation: counter
clockwise. Firing order 1-8-4-3-6-5-7-2.
So now two of us are completely stumped. Any guesses out there as to
what might still be the problem?
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