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JW Aspin Engine Archive

8.6L 6 cylinder engine in Northern Ireland

The photo shows the single decker bus that ran on the Ballymena to Ballymoney. This engine was one of the most reliable and complete of Frank Aspin's creations, due in part to the use of liquid cooled rotors.
Eventually the rotor coating started to breakdown and the engine was taken out of service. It should have been an easy job to replace just one of the rotors, as the design allowed the rotor housing to be unscrewed and the rotor assembly complete taken out, to be replaced by a replacement assembly already shimmed. For whatever reason, perhaps that the engine was different and not sufficiently better to overcome the additional instruction to the mechanics, the refurbished engine did not resume service.

Click to enlarge
The engine then did many years as a [standby] generator for the Aspin factory, and was then bought as an engine to be used in a single decker refurbishment project. When this project was abandoned, and after the engine had lain in a hedge for 10 yerars, the engine was to be scrapped, and not wanting to see such an engine go that way and having seen my Aspin website, it was offered to me for scrap value provided that I go and collect it. So, this is the engine that I acquired in 2002.
Transporting the engine was a challenge for me, as it weighed at least half a tonne. A deal was struck, he would help with the lifting gear and some expertise, I wanted the barrel and head not the standard diesel bottom end, his mate wanted the good crank and shells for a fire engine that he was rebuilding. I would give the crank and matching bigend shells in exchange for a hoist and some help.
See here, during disassembly, the photos show clearly the pipework to feed cooling oil to the inside of the rotors. You can also see clearly the top of the rotor field replaceable unit, the rotor housing to be extracted and replaced in case of rotor failure.
Some of the pistons were stuck in the bore, I used an engine hoist to pull them out. They did come out eventually without additional damage. See the burn marks on this rotor.