Dorman 6LDT Engine Overhaul

Solution

The following components have been measured and inspected;

• Crankcase
• Pistons
• Conn Rods
• Liners (3 were found to be oval and have been rejected)
• Camshaft
• Crankshaft (measured and crack tested)

The crankcase has been cleaned in preparation for rebuild.

All engine components following dismantle were sent for chemical cleaning. Upon return, some items required bead blasting before a visual inspection could be conducted to review any potential areas of concern of damage. None was evident.

In addition the following has been conducted:-

• Inlet and exhaust valves have been cleaned and polished.
• Exhaust pipes have been bead blasted and painted (figure 1).
• Cleaning and painting of quantity three cylinder liners to increase anti corrosion properties (figure 2).
• Bead blasted and painted cam follower carriers (figure 3).
• Stripped and inspected turbo
• Crack detected connecting rods and timing gears (figure 4).

Some heavily corroded bolts and studs sheared when removing engine components. These required machining and re-tapping (Figure 5). These included:-

• Cylinder heads
• Exhaust manifolds
• Turbo housing

Quantity two e bores are partially corroded and will require re-machining or suitable repair under taken.

Plan for next week:-

• Bore repair
• Fit liners
• Pressure test crankshaft
• Check end float to confirm within manufacturers tolerances
• Fit pistons

We have repaired the damaged e bore highlighted last week using Belzona (figures 1-5). It was not necessary to repair the second e bore.

We have drilled out broken and damaged studs and repaired the threads on the Turbocharger (figure 6)

Drilled out the corroded and seized bolts on the exhaust elbow (figure 7)

Drilled out broken and damaged studs and repaired the threads on the exhaust manifold (figures 8 & 9)

Cylinder head valves and valve seats have been cut, cleaned, lapped (figure 10) and vacuum tested (figure 11) to insure correct sealing.

The liners required cleaning and painting and are now ready for fitting.

The crankcase has been re-cleaned following the e bore repairs.

Pistons have been fitted to connecting rods.

The liners have been fitted and the crankcase pressure tested to 60psi for 1 hour. No leaks have been identified.

The crankshaft has been fitted.

It was not possible to check the end float of the crankshaft to confirm within manufacturers tolerances as the tab washers were damaged and require replacing. These are expected to arrive today so this activity can be completed.

We have re-fitted x2 injector tubes and core plugs on both cylinder heads and we have pressure tested to 60 psi for one hour and there were no issues of note.

The oil cooler has been disassembled, cleaned and is being rebuilt. New seals will be fitted. One of the valves will require lapping before assembly to guarantee a complete seal.

Plan for next week:-

• Check the end float of crankshaft to confirm within manufacturers tolerances
• Fit camshaft
• Fit piston and connecting rod assemblies
• Overhaul oil cooler
• Fit timing gears
• Fit cylinder heads
• Fit rocker gear

The damper and water pump will be replaced.