B5.9G, B5.9LPG – Troubleshooting and Repair Manual – 001-026   Cylinder Block

Diagnosis of cylinder block cooling and lubrication malfunctions has been discussed in those respective sections. The potential problems with the cylinder, the camshaft bore, and the crankshaft main journals have also been discussed in this section.

Malfunctions of the cylinder block, such as leaks, tappet bore wear, and so forth, require a visual or dimensional inspection to isolate the problem.

The cylinder bores are machined directly into the cylinder block during production. The size and condition of the cylinder bore are critical to engine performance and life. During repair, be sure to inspect the cylinder bore carefully. It will also be necessary to deglaze the cylinder walls before reassembly. A 30-degree crosshatch pattern is needed to seat the new piston rings.

The cylinder bores can be bored in a machine shop and fitted with an oversize service piston. The cylinder bore can also be bored to accept a service sleeve and standard pistons. Refer to the B Series Alternative Repair Manual, Bulletin 3666109, for boring procedures.

NOTE: The head surface of the block is also critical to sealing the cylinders. Inspect the surface carefully during repair before assembly. The cylinder head deck can be resurfaced in a machine shop and a thicker surface cylinder head gasket installed to keep the piston-to-head clearance the same.

After machining, the cylinder block is stamped at the upper rear right corner surface of the cylinder block as follows:

WARNING  Coolant is toxic. Keep away from children and pets. If not reused, dispose of in accordance with local environmental regulations.

WARNING  Do not remove the pressure cap from a hot engine. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Heated coolant spray or steam can cause personal injury.

Cylinder Bore Deglaze

Drain the coolant. Refer to Procedure 008-018.

Remove the cylinder head. Refer to Procedure 002-004.

WARNING  To reduce the possibility of personal injury, avoid direct contact of hot oil with your skin.

Drain the lubricating oil. Refer to Procedure 007-025.

Remove the lubricating oil pan and gasket. Refer to Procedure 007-025.

Remove the piston and connecting rod assemblies. Refer to Procedure 001-054.

Use a strong solution of hot water and laundry detergent to clean the cylinder bores.

WARNING  Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.

CAUTION  Clean the cylinder bores immediately after deglazing, or premature wear of the bores and rings can result.

NOTE: When cleaning the cylinder bore, perform a cylindrical motion, not a vertical one, to make sure no leak paths are made.

Rinse the cylinder bores until the detergent is removed.

Dry the cylinder block with compressed air.

WARNING  When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.

WARNING  Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.

NOTE: Be sure to remove the tape covering the tappet and lubricating oil holes after the cleaning process is complete.

Check the cylinder bore cleanliness by wiping with a white, lint-free, lightly oiled cloth. If grit residue is still present, repeat the cleaning process until all residue is removed.

Wash the cylinder bores with solvent.

Dry the cylinder block with compressed air.

NOTE: Be sure to remove the covering from the piston cooling nozzles.

Remove the protective tape and cloth, and clean the crankshaft journals.

WARNING  When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.

Use a solvent and a brush to clean any residue that possibly has splashed on the camshaft.

Inspect the camshaft lobes and tappet faces for signs of wear or damage. Refer to Procedure 001-008.

Measure the cylinder bore diameter at 25.4 mm [1 in] and 170.7 mm [6.7 in] from the top of the cylinder block.

Bore inner diameter max – 102.116 mm [4.0203 in]

Bore out of round – 0.035 mm [0.0014 in]

Bore taper – 0.076 mm [0.003 in]

NOTE: Do not proceed with in-chassis overhaul if the cylinder bores are worn beyond specifications.

Deglazing gives the cylinder bore the correct surface finish required to seat the rings.

NOTE: New piston rings possibly will not seat in glazed cylinder bores.

Wrap the connecting rod journals with a clean cloth.

Cover the cloth with waterproof tape.

Place a clean shop towel around the top main bearing saddle to deflect water and residue from the piston cooling nozzles.

Also, cover the lubricating holes and tappet holes in the top of the cylinder block with waterproof tape.

A correctly deglazed surface will have a crosshatched appearance with the lines at 15- to 25-degree angles with the top of the cylinder block.

Use a drill, a fine grit flex-hone, and a mixture of equal parts of mineral spirits and SAE 10W-30 engine lubricating oil to deglaze the cylinder bores.

The crosshatch angle is a function of drill speed and speed of hone’s vertical movement.

This illustration shows the result of the drill speed moving too slow or the vertical stroke too fast.

This illustration shows the result of the drill speed moving too fast or the vertical stroke too slow.

NOTE: Vertical strokes must be smooth, continuous passes along the full length of the cylinder bore.

Inspect the cylinder bore after 10 strokes.

Install the piston and connecting rod assemblies. Refer to Procedure 001-054.

Install the lubricating oil pan and gasket. Refer to Procedure 007-025.

Install the cylinder head. Refer to Procedure 002-004.

Fill the engine with clean gas engine lubricating oil. Refer to Section 7 for the correct lubricating oil specification.

Fill the engine with coolant. Refer to Procedure 008-018.

Operate the engine to normal operating temperature, and check for leaks.