Centinel System – Repair Manual – 001-026   Cylinder Block

Inspect the cylinder block for cracks. If any cracks are found, the cylinder block must be replaced.

If upper bore erosion is discovered during block inspection, it must be disregarded. It is not a failure mode and the use of new o-rings on the cylinder liner provides an adequate seal.

If liner ledge pitting is discovered during block inspection, the block can be reused, if no leak is evident in the liner-to-liner ledge (block) interface.

The main bearing bore diameter must be measured with the main bearings removed and the main bearing caps assembled and torqued to the correct specification.

Refer to Procedure 001-006 in Section 1.

Follow this procedure to salvage capscrew holes that are missing a portion of threads or that have cracks extending into the threaded sidewall from the upper counterbore.

Cracks that extend into the capscrew bosses or the coolant cavity below the upper counterbore can not be salvaged using this procedure.

Remove any burrs from the top deck surface of the cylinder block. A 12 inch flat surface mill file is effective for this step. Burr removal is necessary to obtain an accurate fixture location.

NOTE: The thread salvage kit is designed to be used with the cylinder liner removed. If the cylinder liner remains in the block, shims must be installed to both sides of the base, equally, to bridge the liner.

NOTE: On some engines, it will be necessary to use the spacer, Part Number 3376206, between the mounting base and the drilling fixture.

Select two capscrew holes so the failed capscrew hole is positioned approximately in the middle. Install the mounting plate assembly onto the capscrew holes using the appropriate spacers, four plain washers, and the existing cylinder head capscrews.

Use a heavy washer and the 5/8-18 x 3 inch hex head capscrew to attach the drilling fixture to the mounting plate assembly.

For main bearing capscrew thread repair, mounting plate, Part Number 3164014, will not accommodate all engines. In those cases, the repair must be performed by a qualified machine shop.

Slide the locating pin through the appropriate drilling fixture bushing hole until it rests in the failed capscrew hole of the cylinder block.

Center the drilling fixture guide bar and bushing over the failed capscrew hole.

Tighten the three capscrews to secure the fixture assembly.

Remove the locating pin.

Setting the stop collar is required only for repairs using drills.

Drills are used in some kits to allow for quick removal of waste material; however, care must be taken to make certain the depth of the repaired capscrew hole is not increased beyond specification.

The following steps will result in the drill stopping short of the original hole depth. The remaining material is then removed with the reamer.

Place a 0.76 mm [0.030 in] feeler gauge over the hole to be repaired.

Insert the drill through the drill bushing until its tip rests against the feeler gauge.

Place the thread insert to be installed between the drill bushing and the stop collar.

Move the stop collar down until is rests against the insert and tighten the stop collar.

Place the drill through the drill fixture bushing and let it rest over the top of the failed capscrew hole.

Use a drill motor with a clutch and a maximum operating speed of 300 rpm. Use a suitable cutting fluid. Operate the drill motor until the stop collar contacts the drill bushing.

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

Remove the chips with a chip vacuum.

Place the reamer through the drill fixture bushing and let it rest over the top of the failed capscrew hole.

While reaming the hole, it will be necessary to stop frequently to clean the hole with the chip vacuum.

Use a drill motor with a clutch and a maximum operating speed of 300 rpm, a suitable cutting fluid and operate the drill motor until the reamer reaches the bottom of the original capscrew hole.

The reamer will stop cutting when it reaches the bottom of the hole.

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

Remove the chips with a chip vacuum.

Stop the tapping operation frequently to clean the bore with a chip vacuum.

Install a ½ inch square drive socket on the end of the appropriate tap.

When tapping, keep the tap well lubricated.

Install the tap (4), and use a suitable tapping fluid. Hand-tap to the bottom of the failed capscrew hole.

Remove the tap.

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

Remove the chips with a chip vacuum.

Remove the mounting capscrews, spacers, four plain washers, and mounting plate assembly.

Thread the tap in and out of the newly-cut threads several times to verify the thread condition and clean debris from the threads.

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  Some solvents are flammable and toxic. Read the manufacturer’s instructions before using.

Check the capscrew hole for evidence of porosity and cracks.

Clean the threads and flush any debris from the tapped hole using a solvent-degreasing agent.

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

Remove the solvent-degreasing agent from the hole with a chip vacuum.

Place the appropriate jam nut (1) on an appropriate capscrew.

Install the appropriate thread insert (2) onto the cylinder head mounting capscrew until it nears the bottom of the insert.

Rotate the jam nut (1) until it contacts the thread insert (2) to lock the insert and jam nut together.

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  Some solvents are flammable and toxic. Read the manufacturer’s instructions before using.

Remove the preservative coating from the circumference of the thread insert. Use a solvent-degreasing agent.

Install the thread insert, jam nut, and capscrew into the newly-tapped hole. Make certain the thread insert threads freely into the hole.

NOTE: For applications with a counterbore, measure the protrusion depth starting at the counterbore face, which is recessed into the hole.

Check for protrusion. Make certain the thread insert protrusion is 0 to 1.0 mm [0 to 0.040 in] above the cylinder block surface.

It is important to make certain the minimum required thread depth is maintained after thread repair.

If the insert protrusion exceeds 1 mm [0.040 in], the cylinder head capscrew can bottom out when tightened.

Record the amount the insert protrudes.

It is necessary to increase the depth of the original capscrew hole.

If the insert protrusion is correct, install the insert.

If the protrusion is not correct, record the measurement and adjust the bore depth.

Prior to increasing the capscrew hole depth, check the following:

1. Make certain the correct thread insert is being used. Two inserts are available, two inserts are identical except for their length.
2. Make certain the insert used is the correct length.
3. Make certain the capscrew hole is threaded all the way to the bottom.
4. Make certain there are no burrs or other damage that would prevent the insert from threading to the bottom of the capscrew hole.

After checking the above listed items, if the thread insert protrusion still exceeds 1.0 mm [0.040 in], the depth of the original capscrew hole must be increased.

NOTE: The thread salvage kit is designed to be used with the cylinder liner removed. If the cylinder liner remains in the block, shims must be installed to both sides of the base, equally, to bridge the liner.

NOTE: On some engines, it will be necessary to use the spacer, Part Number 3376206, between the mounting base and drilling fixture.

Install the mounting plate assembly.

Do not tighten the fasteners.

Slide the drill through the drill bushing and into the threaded hole until it rests at the bottom of the hole.

Tighten all fasteners.

The drill must slide freely in the bushing and threaded hole, indicating that it is centered in the hole.

Do not increase the depth of the original capscrew hole more than 3.0 mm [0.120 in].

Slide the stop collar over the drill bit.

Subtract 0.50 mm [0.020 in] from the insert protrusion.

Select a feeler gauge equivalent to this value.

With the drill resting at the bottom of the hole, insert the feeler gauge between the stop collar and drill bushing.

Tighten the stop collar.

Use a drill motor with a clutch and a maximum operating speed of 300 rpm, a suitable cutting fluid and operate the drill motor until the stop collar contacts the drill bushing.

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

Remove the chips with a chip vacuum.

It is not necessary to ream the hole prior to the second tapping.

Install a ½ inch square drive socket on the end of the appropriate tap.

When tapping, keep the tap well lubricated.

Install the tap (4), and use a suitable tapping fluid. Hand-tap to the bottom of the failed capscrew hole.

Remove the tap.

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  Some solvents are flammable and toxic. Read the manufacturer’s instructions before using.

Check the capscrew hole for evidence of porosity and cracks.

Clean the threads, and flush any debris from the tapped hole using a solvent-degreasing agent.

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

Remove the chips and solvent-degreasing agent from the hole with a chip vacuum.

Install the thread insert on a cylinder head capscrew and lock in place with a jam nut.

Temporarily install the thread insert and check the protrusion. Make certain that the protrusion is 0 to 1 mm [0 to 0.040 in] above the cylinder block surface.

Remove the insert.

Apply a light coat of primer, Part Number 3824715, to the thread insert and the threaded hole. Allow three to five minutes to dry.

Apply four beads of thread locking compound, Part Number 3824038, to the circumference of the thread insert.

Each bead must be 0.8 mm [0.03 in] wide down the entire length of the thread insert and the beads must be 90 degrees apart.

Install the thread insert until it is flush with the cylinder block surface or it bottoms in the hole.

Allow to dry for three hours.

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

Remove the capscrew and jam nut.

If necessary, file or machine the top of the thread insert so it is flush with the cylinder block surface.

Make certain that the inner diameter of the thread insert is free of burrs. Remove any file shavings or debris with the chip vacuum.

For applications where the thread insert is recessed into a counterbore, an end mill or a machine cutter will be necessary to remove the excess length of the insert and restore the alignment of counterbore.