Chapter 4 Flashcards
Give a brief explanation of why cylinder ridge must be removed before pushing the piston and connecting rod from the cylinder.
The piston rings will catch the ridge, making the piston difficult to remove and possibly damaging the piston and the rings.
List two safety precautions when using a rotary wire brush to remove a carbon ridge from a cylinder.
Wear eye protection.
Make sure that the wire brush is suitable for the speed of the tool turning it.
In preparation for piston and connecting rod removal, the piston to be removed should be positioned at:
BDC
Explain why it is necessary to remove piston cooling from some engines when removing and installing piston and connecting rod assemblies.
To prevent damage to the piston cooling nozzle.
When removing and installing piston rings, a ring expander should be used to:
To prevent piston and ring damage.
List the parts of the piston that should not be bead blasted.
Ring Grooves
Skirt
Piston pin bores
When scraping carbon from the ring grooves of a piston care must be taken to ensure that:
Metal is not removed from the ring groove area.
What tool should be used to measure wear in a keystone piston ring groove?
Ring groove wear gauge
Pistons should be visually inspected for signs of:
Cracks in the crown, skirt and piston pin bores.
Scuffing and scoring on the skirt, ring lands and crown.
Signs of wear or erosion in the ring grooves.
Looseness or debonding of inserts.
The skirt of a piston should be measured at a point midway down the skirt and ______ to the piston pin bores.
90 Degrees
List three problems that will occur with worn piston ring grooves.
Blowby
Oil consumption
Broken piston rings
Calculate the piston clearances with the following measurements.
Piston skirt diameter: 4.9985”
Cylinder bore diameter: 5.0017”
0.0032”
What would be the result of a piston installed with insufficient clearance between the skirt and the cylinder wall?
scuffing/scoring and eventual piston siezure
Piston pins should be measured to determine:
Minimum outside dimension and out of round.
Calculate the piston pin clearance using the following measurements:
Piston pin diameter: 2.4997”
Piston pin bore diameter: 2.5012”
0.0015”
List the method that can be used to check a connecting rod for cracks.
Dye check.
Magnetic particle.
Magnaflux.
List the three measurements that must be made to determine the condition of the large end bore of a connecting rod.
Bore size.
Out of round.
Taper.
A bent connecting rod will cause:
Uneven wear and loading on the connecting rod journal and bearing, piston crown and skirt, piston pin and bores.
Reduced compression ratio.
Unless otherwise specified by the manufacturer, when installing a full floating piston pin, you should install the gap in the snap rings:
Towards the bottom of the piston skirt.
A full floating piston pin that has a slight interference fit at room temperature should be removed or installed by:
Heating the piston in boiling water or an oven.
Briefly explain how to position a piston ring in a cylinder bore to measure end gap.
Push each piston ring squarely into an unworn area of the cylinder bore.
What would be the result of piston rings being installed with insufficient piston ring end gap?
Piston ring would seize up in the bore.
Briefly explain why piston ring end gaps must be staggered before the piston is installed in the cylinder.
To limit the amount of cylinder pressure, combustion gas and oil leakage that can pass by the rings during engine operation.
When installing connecting rod bearing shells in the rod and cap it is important to check the:
Alignment of locating tangs and oil holes.
