Havengore has twin Gardner 8L3 engines. During her re-fit in April 2006 it was found that the engines needed significant work. The port engine required immediate attention while the starboard engine was in better condition.

All of the work has been undertaken by Ray and Michael Harrison of Gardner Marine Diesels. The work undertaken by Gardner Marine Diesels is described below:

Port Engine:

The port engine was completely stripped down, leaving only the top and bottom crankcase and crankshaft. The dismantled parts were then removed from the engine room via the small exit hatch using a chain lifting system. Main components to be removed were:

• All 8 pistons
• All 8 conrods
• Fuel pump assembly
• 4 cylinder blocks (2 cylinders per block)
• 8 cylinder liners
• All 8 cylinder heads

The above items were transported back to our workshop for cleaning and assessment. The following was found:

• Large score marks were found on number 7 piston and liner and also smaller score marks were found on numerous other piston/liner combinations. These score marks denote a piston seizure, due to overheating of the cylinders.
• Considerable sediment and cylinder block erosion was found in the cylinder blocks. In this sediment, a nut was found from the ram type water pump.
• On removal and dismantle of the water pump, its internals were found to be in pieces, and as a result it would not have been pumping any water around the engine.
• All wet liners were steam cleaned and sandblasted, and were found to be worn.
• The cylinder heads were pressure tested and the valves were tested. It was found that the valves were not seating correctly and required attention.
• The bulkhead-mounted heat exchanger was removed from Havengore and dismantled. A substantial amount of sediment was found internally.

After the above assessment, the following work was carried out:

• All 8 pistons were replaced. New L3 pistons were not available at that time, so new later type L3B pistons were used and machined to the tolerances required by the L3. 8 new pistons ring sets were also used.
• Each cylinder block was thoroughly cleaned and had 0.020” machined off each of its liner registers, to remove any pitting.
• Copper shims of 0.020” thickness were cut to replace the material machined off each cylinder block.
• New L3 wet liners were sourced and purchased, then honed. Each individual liner was lapped into the top of each respective cylinder block to attain the correct seating and therefore water tightness.
• The internals of the ram type water pump that was found to be in pieces was sandblasted and re-assembled using new valves.
• Each of the 8 cylinder heads were dismantled and cleaned. The valves and valve seats were reground and then lapped together again and again until an airtight seal was formed. All inlet and exhaust valve guides were found to be worn, so all were replaced. The heads were tested again.
• The fuel pump damper was reconnected in our workshop, and then realigned.
• All items were finally cleaned before they were transported back on board Havengore.

Before the engine could be reassembled, the top of the crankcase face had to be totally clean. The finding of a thick gasket that had been placed between the crankcase and cylinder blocks hampered this procedure. Due to this surface being a face-to-face joint, the gasket had to be scraped off and the face cleaned with cleaning solution.

The engine was then reassembled using the new/cleaned parts. The piston to cylinder head clearance was checked on all cylinders, and the engine reassembly was completed.

Due to the poor state of repair that the original Gilkes sea water pump was in, and the general bulky nature of the cooling system, it was decided to install a new Bowman heat exchanger/header tank unit, new Jabsco sea water pump and replace the piping. This involved slightly altering the water injection pipe into the exhaust.

Starboard Engine:

The starboard engine was found to be in better condition than the port engine therefore little was done to this engine but a major overhaul is planned for January 2007 during the next re-fit.

The cooling system was all replaced with the new system as used on the port engine.

Both Engines:

• New custom built tachometers were fitted in the wheelhouse for both engines, running off small chain driven generators.
• Remote engine stops were installed as per MCA requirements, as were injector pipe shields.