Recently thinking back to when Sun Traffic Signals first started out (as a specialist traffic light hire service) in January 1992, the power source options for customer's traffic lights, was, to say the least, limited. Quite simply, it was a binary choice of either mains power (cable-linked) OR a cable-linked, diesel generator (completely unsilenced). This hardly seems conceivable now in 2013 when we have possibly third or fourth generation battery powered LED traffic lights.
The diesel engine powering the generator of choice at that time was the venerable Petter/Lister-Petter AA1 which was made in Stroud, Gloucestershire. This single cylinder engine in it's 05 build was a 1500rpm, 1.5hp unit which was (relatively) straightforward to keep working for extended periods of time between servicing and basic maintenance (500 hours).
By relatively, I mean for a skilled and knowledgeable engineer! In order to provide reliable service for customers and to keep the need to de-coke (de-carbonise) to a manageable level, the skilled engineer would need to carry out plenty of regular recorded servicing.
A skilled engineer would carry out the de-carbonisation of cylinder head and exhaust system in less than 2 hours.
Over time, the need to de-coke would become more frequent. Given the correct fuel pump timing, an efficient injector, good compression and regular servicing, this deterioration could be slowed very significantly. Eventually though, all moving engine parts would wear, which is where a greater level of skill was needed for a bump testing and the engine rebuild!
Due to the low engine loads, low RPM and the need to start this engine with a starting handle at very low temperatures, the preferred engine oil for those in the know was a 10W. Using other oil would lead to problems not least the inability to start in near-zero temperatures!
Eventually, the need to silence (acoustically enclose) traffic light engines meant the larger Lister-Petter AC1 was introduced mainly because it could be equipped with an electric starter motor. But I will save that engine the subject for a later blog....