Chevrolet Motor Lacks Power and is Sluggish Troubleshoot
Motor Lacks Power and is Sluggish
This is very apparent when ascending a slight grade or in attempting to accelerate the motor suddenly, and may be caused by the following:
As the motive power is obtained by burning or exploding a highly compressed gas mixture, it follows that a certain amount of carbon will be deposited on the valve seats, piston head and combustion chamber.Small particles of burnt carbon will lodge under a valve, especially the exhaust, holding it open. As this exposes the valve seats to the heat generated by the explosion, small pits or burnt spots will in time cause the surface to be so roughened as to prevent the proper seating of the valves. This will cause a leakage of gases, resulting in loss of power and uneven running of the motor. When this occurs, grinding the valves is the only remedy.
To determine which valves need attention, turn the motor over slowly by hand and note whether the same degree of resistance is met with in each cylinder. The ones offering the least resistance are those whose valves leak. Grinding the valves is the only remedy.
Worn or Broken Piston Rings
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This is sometimes difficult to determine in advance, especially if the valves are badly carbonized and need grinding. By removing the cap from the breather tube and holding the ear to the opening you can sometimes hear the gas “blowing” by the rings. Inasmuch as the cylinder head must be removed to make replacement of rings, it is advisable to examine carefully the valves before going further.
Should the rings be worn they should be replaced.
Replacing the piston rings will not always overcome the “blowing by” of gases if the cylinder walls are worn out of round. An examination should be made to determine whether this condition exists as the new piston rings will only touch the high spots in the cylinder, leaving a space between the rings and the cylinder walls.In this event, the only remedy is to ream or regrind the cylinders or replace the cylinder block.
Valve push rods set up too tight, causing the valves to hold open. With the motor hot, test the push rod clearance and adjust accordingly.
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If the piston starts downward on the power stroke before the spark crosses the gap of the spark plug, the compression is reduced and a portion of the effect of the expansion or explosion of the gases on top of the piston is lost.The ignition timing should be checked very carefully to see that the electric current is being delivered to the spark plug at the proper time.
Badly burned spark plug electrodes, which increases the resistance of the plugs, resulting in a weak spark. Replacing the plug is the only remedy.
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The cooling system consists of a large cellular type radiator and a belt-driven centrifugal pump. As the circulating pump is connected to the lower radiator outlet the water is drawn through the radiator before being delivered to the water jackets surrounding the cylinder walls, which insures a proper circulation of cool water at all times,regardless of engine speed.
Should water leak through the stuffing box on the end of the pump, tighten the nut. If this does not stop the leak, unscrew the stuffing box and wrap around the shaft ordinary candle wicking that has been saturated with tallow or graphite grease and tighten the nut again.
Keep the cellular openings clean.Never allow mud to remain in them as it cuts down the radiation and prevents proper cooling. The entire circulating system should be thoroughly flushed out occasionally. This can be done in ordinary cases by disconnecting both the upper and lower hose connections and allowing fresh water to enter the filler neck and flow down through the radiator and out the lower hose. The motor water jackets can be flushed out in the same way.
When hard water has been used, a scale or deposit will be formed which, unless removed, will obstruct the circulation, causing unnecessary heating and frequent refilling. In this case a good way to clean out the scale is to dissolve a half pound of lye in about five gallons of water.
Strain the liquid through a cloth and pour in the radiator. Run the motor for about five minutes, then draw off the solution through the radiator drain cock.Fill the radiator with fresh water and run the motor again for several minutes, then drain off the solution and refill with fresh water.
Never Use a More Powerful Chemical
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Once a week it is a good plan to open the radiator drain cock and let all the water and accumulated dirt run out. If the water is very dirty, flush the radiator with fresh water.
Never and be sure about this put cold water into the radiator while the motor is hot. By “hot” we mean any temperature which is uncomfortable to the hand when held against the cylinder head.
When a motor gets “hot” the cylinder walls and especially the cylinder head around the exhaust ports are thoroughly heated up. The danger of cracking these ports cannot be overestimated, so make it a point, should you stop for water after the motor has been running for some time, to test the temperature of the motor by raising the hood and placing your hand on the cylinder head.
If you can hold it there with comfort, water can be placed in the radiator; if not, wait until you can. It will only take a few minutes for the motor to cool off, and the repair bill saved will more than offset the slight loss of time and inconvenience.
Leaks in any system subject to vibration are likely to occur. It is not a good plan to put corn meal, bran or other substances in a radiator to stop a leak.It clogs up the tubes, thereby decreasing the radiating efficiency. Make a permanent repair with solder.
Chevrolet Motor Lacks Power and is Sluggish Troubleshoot Article Source – This article courtesy should goes to : Chevrolet Repair Guide of 1923 by Chevrolet Motor Company.