PAXMAN VP185 Seal Service
Seal Service preventative maintenance package carried out for a long standing super yacht client.
Seal Service, basically put, is replacing all of the rubber components within the modern diesel engine and inspecting the components associated with them. In certain applications such as stand-by generators and super yachts, the life expectancy of the rubber components is reached long before the engine reaches its overhaul period, thereby creating the need for a Seal Service.
A Seal Service alleviates those annoying constant breakdowns as the rubber components start to fail causing fuel leaks, coolant leaks, cross contamination of fluids and corrosion damage. We work closely with our clients to build a bespoke program that suits their requirements. We understand that clients have limitations on down time and in certain situations budget limitations. In this project we planned a seal service to be undertaken in three stages thereby spreading the cost and limiting down time.
Stage one was the top end. Exhaust boxes, primary and secondary inter-coolers and exhaust jackets are all serviced and an inspection is carried out to confirm the latest exhaust fixings are in place alleviating any potential deterioration of boost.
Here we can see the beginning of the job. Turbo box lids, turbo cartridges and inter-cooler are being removed and it is at this point the exhaust fixing inspection is carried out to confirm that they are the latest type and correctly secured. Preparation is then carried out for the removal of the turbo boxes.
The turbo boxes are removed to gain access to the secondary inter-coolers. In this instance it was clear that inter-coolers had begun to fail and were in the early stages of complete failure. Pictured are salt deposits building up on the fins within the air side of the cooler and salt build up in the after cooler air trunking. New coolers had to be installed because this evidence of leakage was discovered. This job was carried out just in time, avoiding a potential preventable catastrophic failure.
The secondary inter-coolers and upper exhaust jackets are removed and then cleaned, ready for the installation of the new coolers. With the new coolers in place the upper exhaust jackets are then re-fitted. The turbo cartridges are also stored ready for the rebuild.
All the rubber components removed during this stage of the job have been renewed. The turbo boxes and the overhauled primary inter-cooler are then re-fitted and the engines fully rebuilt. A successful sea trial was then completed and plans were made to carry out stage two the following year.
Stage two was the overhaul of the two main three-stage coolers and the water pumps. The client had mentioned that they were experiencing a slight increase in coolant temperature at full speed which was enough to put the engine into an alarm state. They also mentioned that they had paid particular attention to cleaning the sea water side of the cooler which did not have any effect.
The first job was to remove the two main coolers in preparation for the removal of the water pumps. Once the coolers are removed they are subsequently stripped, cleaned and inspected to identify any potential leakage and replace any damaged components.
During the inspection it was clear that the cooler was in the early stages of failure due to the degradation of the rubber seals as oil could be seen leaking from the lower plates once the cover plates had been removed. The sea water side of the plates luckily showed no sign contamination and were very clean. Unfortunately the fresh water side had developed a problem, a red build up of hard lime scale on the cooler plates had prevented the transfer of heat from the jacket water to the sea water. This in turn was causing the slight rise in coolant temperature. The plates were removed and sent to a specialist cleaning company on site and all new seals were installed.
Both coolers were then rebuilt to the manufacturers specifications and pressure tested across all three sections individually. Once work on the coolers was complete the water pumps were then removed, dismantled and cleaned, ready for inspection.
During the inspection it was clear to see deterioration of the water pump seals. Heavy corrosion had also prevented the successful removal of the seal carrier which had failed during removal. This was then replaced after the inspection had been completed.
The water pumps were overhauled and pressure tested prior to refitting and the coolers were also returned to the vessel and refitted. Once the work was complete another successful sea trial was carried out with all coolant temperatures returned back to normal. The sea trial also revealed that engine performance had also increased, even without the completion of stage three. Once again plans were laid out to carry out stage three the following year during one of the yachts planned maintenance periods.
Stage three of the Seal Service was the removal and inspection of the cylinder heads, pistons, liner seals and fuel galleries, with the replacement of all associated rubber components.
Before any work is carried out the area is prepared and protected with any intakes or outlets sealed to prevent the ingress of foreign object debris. Dismantling then takes place with the removal of cylinder heads, sandwich plates, pistons and liners. Care is also taken to prevent any damage to the crankshaft by sealing all oil-ways and covering any bearing faces with protective material.
The inspection revealed that the cylinder liner seals, although they had not yet leaked, had begun to deteriorate which is a clear indication that the rubber had exceeded its expiry date. The inspection of a removed cylinder head revealed some corrosion which was a little unexpected, but was nothing compared to what was found when examining its corresponding piston and liner. In these powerful modern diesel engines, condensation is a very real problem, the production of water in the inlet manifold occurs regularly and this water must be allowed to escape. This happens by means of condensate valves. These valves need to be maintained rigorously because this condensation (water) has to be ejected from the engine. If one of the valves becomes blocked and water is allowed to remain in the engine it begins to permeate through various inlets and once the engine is shut down starts to contaminate large sections of both sides of the engine.
Once all of the corrosion was removed and a further inspection carried out all the liners and pistons were re-fitted with new seals. The sandwich plates were also overhauled and re-fitted with new seals. The cylinder heads had all corrosion removed and had the injector pockets removed and cleaned before being refitted with new seals. The heads were also cleaned and pressure tested prior to re-fitment. Once all the work was carried out, the engine and surrounding area were returned to the state they were found in with all blanks and covers removed and any contamination cleaned. A third and final sea trial was carried out with the client very pleased to have avoided a couple of major incidents. Both engines are once again serviceable for a further 15 years service.
Throughout this entire project all the special tooling and equipment required to carryout this in-depth service was supplied to site by K.W Engineering Services Ltd.
This extensive service caused no inconvenience to the owner as all works were completed in the off season, and the burden of cost was spread over a three year period.
K.W Engineering Services Ltd apply this level of care and attention to every client, ensuring they receive the most cost-effective service whilst maintaining the safety and reliability of their customers engines.