Cylinder Bores
IMPORTANT: The cylinder bores are chrome and cannot be rebored or efficiently honed. (Honing of a chrome cylinder is not necessary or recommended.)
d. Steps "b” and "c” may require repeating several times before all the aluminum deposits are gone.
e. Check each cylinder for an out-of-round (”eggshaped”) condition. Using an inside micrometer or telescopic gauge, as shown below, take 4 measurements 1/2" (12.7mm) from top of each cylinder bore 45° from each other. A .006" (0.152mm) or less out-of-round is acceptable. If out-of-round is more than .006", cylinder block and crankcase cover must be replaced.
1. Carefully inspect chrome surfaced cylinder bores for signs of flaking, grooving, scoring or other damage.
IMPORTANT: DO NOT mistake porosity for a damaged cylinder.
f. After cleaning and inspection, cylinder bores should be swabbed several times with light engine oil and a clean cloth.
2. If chrome surfacing is flaking, 0r ifa groove or any other mark penetrates the chrome surfacing to the aluminum portion of cylinder block, cylinder block and crankcase cover must be replaced.
3. To determine ifa groove or any other mark in cylinder wall penetrates chrome surfacing to the aluminum portion of cylinder block, apply a small amount of muratic acid (or toilet bowl cleaner) over the groove or mark. [DO NOT allow the muratic acid (or toilet bowl cleaner) to contact the aluminum portion of cylinder block] If a groove or mark penetrates the chrome surfacing, a "fizzing" action (or "bubbling” action) will appear, thus indicating aluminum is being dissolved.
4. If a piston(s) is scored and has transferred aluminum to cylinder walls, remove the aluminum, clean cylinder walls and inspect cylinders for further damage, as follows:
a. Remove all loose aluminum deposits from cylinder walls with a stiff bristle brush.
b. Apply a small amount of muratic acid (or toilet bowl cleaner) onto the aluminum deposits. [DO NOT allow muratic acid (or toilet bowl cleaner) to contact the aluminum portion of cylinder block] A "fizzing" action will appear, thus indicating that aluminum is being dissolved.
c. Leave the acid on the aluminum deposit for one to 2 minutes, then wash cylinder thoroughly with hot water and detergent.
Measuring Cylinder Bores
4-22 - POWERHEAD
90-43508 884