Reliability

[David Morris]

Hi All, The latest Jowetteer ( August 2017 ) has a mention on Javelin reliability ( and by inference Jupiters too? ). Having had some 53 years relationship ( bit like a marriage really! ) with the marque, can I add my thoughts? I suggest that any poor reliability can be down to two factors, firstly inherent design problems and secondly problems stemming from running a car that is 70 years old.
Yes, unfortunately let’s face it, there are design problems that we struggle to mitigate. The engine is prone to a sudden loss of oil from the poor design of the oil filter rear timing case body and the flexible oil bypass pipe. I have had both these happen to me on the road and it focuses your attention to the oil pressure gauge! The rear timing case cover design, meeting the crankcase in a vee, really should never have left the drawing board. Yes, we can improve things with modern ‘o’ rings and very careful selection of matching covers, but let’s face it, it was a rubbish design, with securing bolts at the tips of the vee, and ones coming in from the front cover that tend to pull it out of square. The rear position of the radiator means it has to be in perfect condition to avoid overheating and Jowett’s first attempt with designing a water pump was not really successful, with the thing stuck on top of the crankcase on flimsy legs, almost as an afterthought, which I read somewhere was indeed the case? The gearboxes, especially those manufactured by Jowett’s, are not strong and I have experienced one stuck in first gear that was very hard to cure. The propshaft is prone to vibration and the rear Layrub coupling is running at an angle that is beyond the allowable manufacturer's design limits. The front wheel bearings are plain ball races, when others might have used adjustable taper rollers. Having admitted to these inherent problems that were there from new, the cars are addictive, a pleasure to drive and make you smile! I can cheerfully overlook these problems when considering the competition at the time and the wealth of good design points that are present. The gearchange is a delight to use, the steering is positive and the comfortable ride equal, or better, to many moderns. A Javelin or Jupiter ‘on song’ is great!

So, having tried to mitigate the inherent problems, are there things that also affect reliability today? Yes, the cars are often not used enough over the year and will suffer, as will any make of classic car, from stagnation. The petrol tanks get loaded with crud and, unfortunately, water from filling stations, the electrics suffer from corrosion, brakes need use to avoid imbalance and generally the cars need very frequent servicing all round. How many owners apply grease at the recommended 500 mile frequency? The welcome dispensation to avoid having the legal requirement for MoT’s may instil a misguided feeling of ‘let’s repair when it fails’, which could be fatal or result in the government's leniency to us being withdrawn. Having someone else look over your car annually means they might spot something that you missed, assuming that you do actually examine the underneath? The front suspension and steering is robust but needs frequent servicing. Yes, there are lots of things, like the later ball joints and all drop arms to adjust, but I have seen Javelins that have way too much play on swivel pins and steering cones. Have you ever tried correcting the play at the steering wheel by using the eccentric bush in the Javelin steering box?

That owners can successfully drive to rallies from one end of the country to the other is a tribute to their dedication and to the inherent strength of the design, but regular servicing and being aware of what to look for is so important. I think Javelins and Jupiters are special and only the support of our club, the members and the excellent spares organisation will keep them on the road and avoiding breakdowns.

Perhaps members can suggest a list of areas that we need to check frequently, now that we are left to our own devices, unless we fork out voluntarily for the 'test'. I had the bolt that carries the brake and clutch shaft practically fall out on the way to the Crieff Rally, and that just needed a spanner check now and then to avoid a potentially disastrous failure.

Let's keep them safe and running!

David