Servicing a V12 E-Type

Since we opened, we have seen a range of Jaguar V12 E-Types enter our workshops. We currently have three Series 3 E-Types in the workshop: one undergoing suspension work with our experienced restoration technician, another receiving repairs in the metal workshop, and the third is in the main workshop for tuning. As Jaguar restoration specialists, we wanted to take this opportunity to highlight some of the common issues that arise with the V12 E-Type. These Jaguars are iconic, but their complexity means they demand expert care, especially now that these vintage vehicles are over 50 years old. From fuelling and cooling challenges to electrical reliability and suspension wear, our team has the knowledge, experience, and in-house facilities to address these issues properly. With decades of experience and a proven track record, we believe we are the best equipped to keep these magnificent Jaguars both reliable and enjoyable to drive.

Engine

A common issue we see at the P&K Thornton workshops is the Series 3 V12 engines overheating. The 5.3 litre V12 engine was fitted in the series 3 Jaguar E-Type to appeal to their biggest export destination – America, who wanted more power, smoother performance and better refinement. Additionally, the Jaguar was made a little longer and wider, with power steering to make it a more comfortable ride. The Jaguar V12 produces a lot of heat, especially with four carburettors sat right above the engine, so the factory cooling system has to work hard to keep the engine temperatures under control.

Carburettor Tuning

The Series 3 V12 uses four Zenith-Stromberg carburettors, compared to the earlier E-Type models, which used SU carburettors. To ensure each carb balance is correct and the Jaguar is fine-tuned, we will place the E-Type on our in-house state-of-the-art rolling road. Our rolling road dyno allows us to make precise adjustments to ensure the mixture is not too rich or lean to maximise performance and reliability.

Ignition System

Overheating is one of the most common issues with the Series 3 E-Type, which is why many Jaguar owners today get upgraded fans or improved radiators to help with cooling. However, another frequent challenge is hot starting. When the engine is hot and is shut off, residual heat in the engine bay can cause fuel vaporisation in the carburettors and fuel lines, which can also affect the ignition system, preventing the E-Type from turning on when it’s hot. Therefore, provisions are needed to help control the heat in the engine bay to ensure reliability. We use the SNG Barratt ignition conversion kit to replace the original Lucas OPUS ignition system. This kit offers a more consistent spark performance and improved hot-start reliability. Additionally, it retains the Jaguars’ original look, so the E-Type’s historic appearance isn't compromised. The kit includes a redesigned distributor, an amplifier, a ballast resistor and an upgraded ignition coil.

Rear Axle and Fuel System

In addition, the Series 3 E-Type can have issues with the rear axle and fuel lines. The Series 3 E-Type carries extra weight and stress due to the larger engine and slightly wider and longer body. Components like bearings, seals, and mounts must be checked or serviced regularly, as they are more likely to wear out over time. Along with issues with the rear axle, the Jaguar Series 3 E-Types can have corroded fuel lines, tanks or unions. This creates safety risks and reliability issues. Therefore, it’s essential to maintain the fuel system to prevent leaks, improve reliability, and ensure the Jaguar is safe to drive. 

Wiring and Electrics

Additionally, because the Jaguar Series 3 E-Type V12 engine generates a lot of heat, this can cause the wiring insulation to crack and melt. This can cause short, intermittent faults or failures. The main areas affected include the engine bay harnesses, ignition wiring and the lighting and fuel pump circuits. Faulty wiring can cause fires, issues with the engine or electrical failures; therefore, it is critical to check for these issues in a service or inspection. Often, wiring and electrical problems that are caused by the engine bay overheating can be repaired by completing a partial or full rewiring. In addition, adding heat shielding and correct routing can prevent repeat problems.

Exhaust System

Exhaust components on the Jaguar V12 engine are tightly packed, making leaks both common and difficult to repair. Some common issues include cracked manifolds or joints, rusted or corroded pipes and leaks around connections. These repairs can be challenging, but with our specialist restoration team at P&K Thornton Restorations, you can be confident that any repairs will be completed to the highest standard. With nearly six decades of experience and hundreds of classic cars in our portfolio, we have the experience to overcome a lot of the challenges that come with restoring and repairing these systems. Addressing exhaust faults is essential not only to prevent fumes from entering the cabin but also to maintain the Jaguar V12’s performance.

Servicing and Inspecting your Jaguar V12 at P&K Thornton

As classic Jaguar specialists, for street, fast road and race use with 57 years of experience, we are well equipped to handle a variety of services and repairs on your Jaguar V12. Our specialist restoration technicians have a vast wealth of knowledge and experience to complete any service or repair to the highest standard. If you are interested in booking any of our services for your V12 E-Type, please contact us with confidence. Call us on 0115 926 2266 or email us at info@thorntonrestorations.com.