Repair damaged or worn threads. Cylinder bore-honing

Repair damaged or worn threads

CAUTION: Be sure that the tapped holes maintain the original center line.

Fig. 8 Oil Filter Sealing Surface-Typical

1 - SEALING SURFACE

2 - RUBBER GASKET

3 - OIL FILTER

Damaged or worn threads can be repaired. Essentially, this repair consists of:

• Drilling out worn or damaged threads.
• Tapping the hole with a special Heli-Coil Tap, or equivalent.
• Installing an insert into the tapped hole to bring the hole back to its original thread size.

Cylinder bore-honing

Before honing, stuff plenty of clean shop towels under the bores and over the crankshaft to keep abrasive materials from entering the crankshaft area.

(1) Used carefully, the Cylinder Bore Sizing Hone C-823, equipped with 220 grit stones, is the best tool for this job. In addition to deglazing, it will reduce taper and out-of-round, as well as removing light scuffing, scoring and scratches. Usually, a few strokes will clean up a bore and maintain the required limits.

CAUTION: DO NOT use rigid type hones to remove cylinder wall glaze.

(2) Deglazing of the cylinder walls may be done if the cylinder bore is straight and round. Use a cylinder surfacing hone, Honing Tool C-3501, equipped with 280 grit stones (C-3501-3810). about 20-60 strokes, depending on the bore condition, will be sufficient to provide a satisfactory surface. Using honing oil C-3501-3880, or a light honing oil, available from major oil distributors.

CAUTION: DO NOT use engine or transmission oil, mineral spirits, or kerosene.

(3) Honing should be done by moving the hone up and down fast enough to get a crosshatch pattern.

The hone marks should INTERSECT at 50 to 60 for proper seating of rings (Fig. 9).

(4) A controlled hone motor speed between 200 and 300 RPM is necessary to obtain the proper crosshatch angle. The number of up and down strokes per minute can be regulated to get the desired 50 to 60 angle. Faster up and down strokes increase the crosshatch angle.

(5) After honing, it is necessary that the block be cleaned to remove all traces of abrasive. Use a brush to wash parts with a solution of hot water and detergent.

Dry parts thoroughly. Use a clean, white, lintfree cloth to check that the bore is clean. Oil the bores after cleaning to prevent rusting.

The hone marks should INTERSECT at 50 to 60 for proper seating of rings (Fig. 9).

Fig. 9 Cylinder Bore Crosshatch Pattern