So, what constitutes an upgrade? And is it homage or is it sacrilege? In the grand scheme of things, does it really matter? It’s your car and your own choice. What’s more is that most upgrades, if not all, are completely reversible, but why would you?

In our experience, once upgrades are carried out and the benefits enjoyed, downgrades are rare. That said, a very important consideration to take into account with all upgrades or improvements is, are they really necessary? For example, if your engine is continually overheating, you don’t necessarily need to fit a bigger radiator, you just need to find out why it’s overheating and fix this first.
So why do any of this at all? Well, whilst all of this stuff worked just the way that it should when the cars rolled off the production line back in the day, we have to remember that they were conceived in a different era when, for example, there was much less traffic on the roads. The numbers are simply incomparable to today where the chance of being stuck in mile after mile of heavy traffic is exponentially higher. So, is the ability to dial in a more powerful and, crucially, more controllable electric cooling fan a good idea? Absolutely.
Additionally, upgrades such as these have been designed and engineered with a keen eye to sympathetic and historically respectful fit and function.
This way, they become part of the machine and work in harmony with it as opposed to looking like the Mr. Fusion that appeared rather garishly planted on top of a well-known time-travelling DeLorean.
Our range of superior quality and aesthetically pleasing aluminium radiators, with or without integral modern fan options, aluminium water pumps and coolant header, are a very popular and visually enhancing upgrade. And our cloth-wrapped silicon cooling hoses that closely resemble standard hoses, offer significantly improved integrity as temperatures rise under the bonnet on a warm day in a traffic jam.
Some upgraded parts offer an improved driving experience. Take our Mangoletsi throttle cable conversion, for instance; it’s a precision engineered, well thought out, race-developed twin cable system that reduces free play to zero and drastically reduces lost motion and friction. It contains a fully adjustable pedal and housing and even allows for the placement of the pedal pad to be located just where the driver requires it to be. Throttle response is instant while the cleverly designed and patented adjuster allows the rate of throttle opening to be fine-tuned using just one screw.
The standard, soldered brass carburettor floats are prone to developing holes over time which results in them filling with fuel and sinking to the bottom of the chamber leading to fuel overflow. The StayUp® float is resistant to modern ethanol-based fuels and has a military spec closed cell construction, making it puncture proof.

With the carburettor functionality and throttle performance now optimised, our ITG/Mangoletsi air filter assembly significantly simplifies and declutters the original air intake set up. When correctly set up and tuned with UO needles, it can offer an increase in power output. We achieved an increase of 11.5 BHP or a 5% increase when fitted to our own Series One 4.2.
With most of us having a modern and hopefully reliable daily drive that has long service intervals (some might argue, too long), I suspect that many of us have forgotten things like the need for checking the contact points, lubricating the distributor or cleaning and gapping the spark plugs every 3000 miles. Now I know that there will be folks out there that will argue that this is a therapeutic exercise, it’s part of owning a classic and the system works just fine. This may be true, but modern technology does offer a perfectly packaged, compact alternative to this classic ritual with the 123 Ignition distributor from SNG Barratt.
All moving parts such as the points and centrifugal advance mechanism can now be controlled by the electronics inside. Different advance curves can be applied through a selection of internal pre-sets to optimize the dwell angle throughout the rev range, maximising performance and efficiency.
These settings can be easily adjusted on the distributor itself, or via USB or even a Bluetooth interface depending on the model you choose. If you would prefer to keep the standard points and condenser system, the Lucas “Sport Coil” offers a period correct performance upgrade along with modern silicone plug leads for extra protection against moisture ingress.

Just being produced and used in various forms and many different vehicles from the late 1940’s to the early 1990’s, is tribute indeed to the excellent design and engineering. Admittedly, by the end of production, the design was getting old, but that kind of lifespan is rare in modern times. However, maintained appropriately, these long stroke engines produce excellent torque from very low revs and are also extremely reliable.
As well-engineered and accurately assembled from quality parts as these engines were, they were still built to a price, if William Lyon’s reputation stands under any scrutiny! In other words, they weren’t intended to last forever.
Detailed maintenance intervals, as defined by the factory, were essential to the longevity of the unit. That said, it is probably fair to say that its design life was not meant to exceed mileage much over six digits. In an ideal world, with all required work carried out on schedule, pretty much any component could either be reworked, repaired or replaced, and many well-kept examples can be stripped to find only minimal wear on essential areas such as the bores and crankshaft etc. It’s certainly not rare to see a mild rebore to the first oversize or a crank regrind that offers a fresh lease of life. In some cases, even standard pistons and bearings can be used. However, this isn’t always the case as many worn engines are kept running until something really breaks or the engine overheats, and the cylinder head warps, or the oil pressure gets so low that the engine seizes. Generally, if a cylinder head warps, a machine shop will be able to fix it.
It’s the same after corrosion has taken hold, it can normally be welded and resurfaced. That said, there is only a finite amount of material that can actually be removed, and it is often the case that an oversize gasket will be needed to compensate.
We offer a number of solutions for thicker gaskets in addition to composite materials that offer superior sealing of the combustion chambers and oil and water galleries.
Another common issue is where the steel tappet bucket guides come loose in the aluminium cylinder head and need to be retained by other means to prevent noise and excess wear. Our tappet hold-down kits offer a neat and simple to install solution whereby retaining plates are fitted and held in place with appropriately sized self-tapping setscrews, a job easily carried out at home without the need to employ a mechanic or machine shop. Oil is supplied to the head via a rigid oil feed pipe from the block, which can crack at the banjos over time. A flexible stainless steel braided hose upgrade with swaged fittings and s/s banjos is an ideal and easily installed item.
The hefty crankshaft has a large rope-type oil seal at the rear or flywheel end, and employs a standard rubber lip seal at the front or timing chain end. Often installed incorrectly, without the proper sizing tool (or not soaked in oil first, or even just old and tired), the crank seals, both front and rear, will fail at some point. Leaking oil from the crank rear seal can soak and cause the clutch to fail if the front is leaking too. But hey, if your Jaguar is leaking oil, it’s only marking its territory, right or just helping to keep your garage floor lubricated?


A conversion kit is available to install a rubber lip seal at the rear of the crank and replace the rope seal set up. However, since this requires some simple but nonetheless essential machining, the crankshaft will need to be removed in order to carry this out.
At the timing chain end, the front crank seal can be replaced by an uprated Teflon seal which will offer significantly improved sealing for years to come. The good news about this “Dowty” seal upgrade is that it doesn’t require any machining or, indeed, any specialist tools to install. An ideal time to include this particular improvement would be when doing a timing chain job. Uprated “Iwis” duplex chains with split chamfered rollers offer a superb quality improvement that won’t break the bank either.
If its convenience you seek, a spin-on oil filter conversion has to be near the top of the list in terms of ease of installation and practical advantage. Take the hassle out a filter change with modern filtration technology and no mess on the shop floor.
Finally, why not go for a compact uprated starter motor that requires far less current to crank the engine over?
They offer over 200% more cranking power, are considerably lighter than the beefy heavyweight original units and are easy to replace. So, that’s it and you’ll end up choosing what to do next. You may also choose to do nothing and conclude the engineers back in the day made a pretty good job first time around, but remember they were working with limitations, road conditions have changed significantly and modern technology can be used in perfect harmony to support these beautiful old cars as they continue to age.

Either way, we hope you get the drive you are looking for.