Fitment: DB4, DB5, DB6, DB6 Mk2, DBS

Initially available in 3.7L capacity in the DB4, Tadek Marek’s straight-6 engine is one of the great powerplants of the 1960s. Designed to be able to handle capacity increases in the future, as well as to power Aston Martin’s race cars alongside their road-going grand tourers, the capacity was increased with the introduction of the DB5 to 4.0L by using a larger cylinder bore fitted with larger liners. Aston also produced 2.5L (DBR4) and 3.0L (DBR3) variants of the Tadek Marek 6-cylinder engine, however the road cars would continue to be 4.0L until the introduction of Marek’s famous V8.

For customers wanting a performance increase over the standard 3.7L or 4.0L engine, our 4.2L upgrade offers a notable improvement in power and torque. Achieved by boring out the cylinder liners, the 4.2L engine capacity gives an increase in performance throughout the rev range. As the increase in capacity is achieved by a bore change it is possible to retain many of the original engine components, depending of course on their condition. New pistons will be required however the rest of the engine is theoretically the same. In practice there is nearly always a need to replace other components so as to ensure the engine will be set up for a long usable life.

In terms of carburation, increases to 4.2L in capacity can be carried out with no changes. We have built DB4 engines that retain their twin SU set up (as in our DB4 Bullet engine), while other customers have chosen triple SU (standard on DB5 onwards) or triple Weber (DB4 GT/DB5 Vantage spec) carburation. We’ve found that our 4.2L engine upgrade combined with standard triple SU HD8 carburettors is a very usable and enjoyable powerplant, especially when paired with our lightweight forged crank, and is the most common specification chosen by our Ultimate DB5 clients. Once the capacity upgrade has been carried out, your engine will be thoroughly tested and run-in on our dynamometer; you’ll be provided with a confirmed power and torque figure upon the completion of our testing program.

For the ultimate peace of mind, consider using one of our in-house developed and produced engine blocks. Designed to be stronger, more corrosion resistant and thermally more stable than the original 1960s-produced units, our engine blocks are ideal for big-capacity upgrades. Importantly, no other components need to be changed to allow for the use of one of our blocks, and they are visually indistinguishable once in the engine bay. Click here for more details.

To enquire about any of our enhancements and upgrades, or to discuss a bespoke solution for your car, contact our workshop team at astonworkshop@aston.co.uk or +44 (0) 1207 233 525.