Motor Noise: Mechanical

Possible Causes

   Poor oil or lack of oil

   Foreign matter in engine, such as loose nut in engine base

   Carbon deposits in combustion chamber

   Incandescent spark plug points or carbon particles

   Play in valve operating mechanism

   Loose connecting rod big end bearings

   Loose cylinder head retention bolts

   Loose flywheel

   Loose writs pin bearings

   Worn main bearings

   Worn timing gears

   Worn cylinder, out of round

   Worn piston, permitting side slap

   High piston

   Tight piston rings

Motor Noise: Other Problems (Knocking)               

Possible Causes

   Too much gasoline mixture

   Carburetor float chamber flooding

   Spark timed too early

   Climbing steep hills in high gear

   Overheating due to defective cooling

Motor Noise: Muffler Explosions

Possible Causes

   Mixture not exploding regularly

   Exhaust valve sticking

   Dirt under exhaust valve seat

   Sticking breaker points

   Ruptured muffler

Motor Noise: Popping or Blowing in Carburetor

Possible Causes

   Not enough gasoline (open needle valve)

   Spark retarded too much

   Weak battery

   Incorrectly timed inlet valves

   Inlet valve not seating

   Defective inlet valve spring

   Dirt under inlet valve seat

   Pitted contact points on timer

Motor Noise: Hissing and Squeaking

Possible Causes

   Poor lubrication (causes squeaking)

   Leaking or ruptured muffler

   Leaking around spark plug

   Leaking cylinder head packing

   Loose joint between motor and exhaust manifold

   Loose valve spring chamber cover

   Broken insulation on spark plug

   Broken piston rings (blowing sound)

   Tight piston rings (scraping sound)

Motor Noise: Grinding Sounds

Possible Causes

   Defective cylinder lubrication

   Worn driving gears

   Worn change speed gearing (not noticed on direct drive)

   Worn timing gear

Starting Problems: Ignition

Possible Causes

   Ignition switch off

   Loose terminal on coil or switch

   Loose battery wire on terminals

  Corroded battery terminals

   Weak storage battery

   Dirty timer points

   Dirt or water in timer casing

   Carbon deposits or oil between plug points

   Burnt or pitted platinum contact points

   Spark plugs points too close together or too far apart

   Ignition timer wrong, spark too late or too early

   Stuck breaker points

   Stuck contact maker lever

   No contact at points

   Poor contacts at timer

   Poor contact at switch

   Broken spark plug insulation

   Broken timer contact spring

   Defective or poor battery ground wire

   Defective induction coil

   Defective park plug (no spark at plugs)

   Defective platinum points in timer

   Defective ignition lock

   Short circuit in battery wire (grounding battery)

   Short circuit or break in primary wires

   Short circuit in ignition wire

   Short circuit in secondary coil

   Short circuit in distributor

Starting Problems: Fuel Supply

Possible Causes

   Tank shut-off closed

   No gasoline in tank

   No gasoline in carburetor float chamber

   Not enough gasoline at jet

    Gasoline old or stale

   Gasoline level too low

   Gasoline level too high (flooding)

   Gas mixture too lean

   Cylinders flooded with gas

   Clogged filter screen

   Clogged filler cap vent

   Clogged fuel supply pipe (dirt or water)

   Choke control stuck

   Dirt in float chamber

   Dirt in sediment bulb (full of dirt)

   Float valve stuck

   Broken choke control

   Bent or stuck float lever

   Leaky float (causes flooding)

   Loose or defective inlet manifold

   Water in carburetor spray nozzle

   Carburetor frozen (winter only)

Starting Problems: Mechanical

Possible Causes

   Broken exhaust valve spring

   Broken crankshaft (rare)

   Broken timing gears (rare)

   Frozen pump impeller (winter only)

   Leaky head gasket

   Piston rings gummed to cylinder

   Seized pistons or dry pistons

   Valve gears out in time

   Valve stuck (rare)

   Water or rust in cylinder

Starting Problems: Starter

Starter Will Not Turn

If the starter will not turn, try the following:

1.Verify that the starter pedal is not sticking and goes all the way down.

2.If the pedal sticks, disconnect the storage battery under the seat

3.See if the starter will engage. If the starter spins, "nurse" the pedal until gear engages. In automatic shift systems, make sure the spring is not broken or pinion is not stuck to the thread on the shaft.

4.Firmly connect the main leads between the battery switch and starter (especially at the battery and starting switch).

5.Start the car using the manual crank and drive to the nearest service station.

Starter Turns, But Motor Will Not Fire

If the motor will not fire, do not continue to "churn" the motor. Instead, check for the following problems:

   Loose battery wire at either terminal

   Air lock in gasoline pipe or tank

   Inlet valve stuck open

   Insufficient lubrication

   Piston seized on account of defective oiling

   Bent or broken camshaft or crankshaft (rare)

   Seized main bearings (rare)

   Flywheel wedge by foreign matter in engine base (rare)

   Sheared key in crankshaft gear operating valve mechanism (rare)

Motor Stopping Problems: Will Not Stop

Possible Causes

   Overheated engine

   Throttle remains open

   Throttle has jarred open

   Spark interrupting switch out of order

   Incandescent carbon deposits fire charge

   Timer casing advanced

   Clutch slipping or released

Motor Stopping Problems: Gradual Stops

Possible Causes

   Loose terminal at battery

   Motor overheating due to defective oiling or cooling

   Clogged fuel supply pipe (partially clogged)

   Clogged air vent in tank filler cap

   Clogged spray nozzle (water or dirt)

   Mixture adjusting needle jarred loose

   Sticking contact points

   Float needle valve stuck

   Valves stuck open

   Broken spark advance rod

   Broken throttle rod

Motor Stopping Problems: Stops Without Warning

Possible Causes

   No gasoline in tank

   Gasoline shut off valve jarred closed

   Air lock in gasoline pipe or tank

   Battery wire loose at either terminal

   Broken primary wire

   Broken timer spring (rare)

   Ignition short circuited by ground in wire

   Clogged gasoline supply pipe

   Clogged spray nozzle (dirt or water)

   Particles of carbon or oil between spark plug points

   Insufficient lubrication

   Pistons seized on account of defective oiling

   Inlet valve stuck open

   Bent or broken camshaft or crankshaft (rare)

   Seized main bearings (rare)

   Flywheel wedge by foreign matter in engine base (rare)

   Sheared key in crankshaft gear operating valve mechanism (rare)

Motor Loses Power: Poor Compression

Possible Causes

   Loose spark plugs

   Sticking contact points

   Broken spark advance rod

   Broken throttle rod

   Defective cylinder head gasket

   Loose head casting on cylinder

   Leaky valves (regrind)

   Warped valve heads

   Piston ring joints in line

   Worn piston rings

   Cracked piston or cylinder head (rare)

Motor Loses Power: Other Causes

Possible Causes

   No water in radiator

   Broken or loose fan belt

   Overheating due to driving with retarded spark

   Overheating due to racing motor on low speed gear

   Overheating due to too rich mixture

   Overheated or dry cylinder

   Oil too light

   Oil carbonized at too low temperature

   Oil feed interrupted

   Choked muffler

   Defective pump

   Exhaust valve lift insufficient

   Carbon deposits

   Tight bearings

Note: All causes contributing to irregular motor action also causes lost power.

Motor Runs Irregularly or Misfires: Mechanical

Possible Causes

   Air leak in inlet piping

   Air leak through inlet valve guides

   Broken cylinder head gasket

   Sticky valve stems

   Weak or broken valve springs

   Carbon deposits in combustion chamber

   Carbon under valve heads

   Worn push rod or guide

   No clearance between valve stem and plungers

Motor Runs Irregularly or Misfires: Fuel Supply

Possible Causes  

   Too much gasoline, carburetor flooded

   Poor gasoline

   Water or dirt in gasoline

   Poor gasoline adjustment

   Not enough gasoline in float chamber

   Carburetor float chamber getting dry

Motor Runs Irregularly or Misfires: Racing Motor

Possible Causes

   Throttle not closing

   Timer stuck in advance position

   Clutch slips (in high speed)

   Control rods broken

   Defective induction pipe joints

   Leaky carburetor flange packing

Motor Runs Irregularly or Misfires: Ignition

Possible Causes

   Weak battery

   Loose wiring or terminals anywhere

   Prematurely grounded primary wire

   Broken wire inside of insulation

   Broken spark plug insulator

   Defective condenser in coil

   Dirty spark plug points (sooted or oily)

   Dirt in battery timer

   Pitted platinum points on timer

   Gummed oil in timer or distributor

   Weal spring, timer bell crank

   Wrong spark gap at plug points

   Poor adjustment of contact points at timer

   Worn points in timer

   Leaking secondary distributor head

Motor Runs Irregularly or Misfires: Will Not Speed Up

Possible Causes

   Throttle stuck closed

   Dragging brakes in hubs

   Driving system parts not in alignment

   Air choke valve in carburetor air pipe stuck closed

   Timer stuck in retard position

   Valves timed late

   Spark timed late

   Not enough oil in engine base

   Bent or sticking valve stem

   Too much plan in valve operating plungers

   Too much space between valve stems and push rods

   Pistons binding in cylinder

   Binding contact bell crank

Back Fire

Possible Causes

   Look for a leak in the exhaust. Often a cracked exhaust 

   manifold causes this

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Model A Ford Troubleshooting Checklists