Fortunately, some more very good parts were employed during the previous build, including Carrillo connecting rods fitted with ARP Custom Age 625 bolts and a Moldex billet crankshaft. To ensure a bulletproof bottom end, we fitted the block with ARP main studs to accommodate special main cap supports made of billet steel.

Front and Rear of the Crank

Like so many other British engines, the A-series rear main seal features a scroll on the crankshaft. The idea is that stray oil will be pulled into a drain cavity in the bearing cap. Alas, it doesn’t always work so well, giving A-series engines a reputation for seepage.

The folks at Moss Motors have developed a kit that adds a conventional rubber seal to the equation. A seal housing simply bolts to the block, and it can be retrofitted to an assembled engine to provide extra protection from oil leaks.



An oft-overlooked but important component is the harmonic balancer. Our OEM-type damper had a decaying elastomer, so for the sake of safety we replaced it with a BHJ billet-steel unit. The new damper–the one shown in front of the old piece–is fully SFI 18.1 certified, meaning it won’t come apart during competition use. The BHJ piece is also machined with degree marks, which helps in tuning.

Coming on the Cam

We also wanted to replace the camshaft. David Vizard’s 500-plus-page tome “Tuning the A-Series Engine” explains the scatter camshafts designed and developed by A-series guru David Anton of APT Performance.

The A-series engine features Siamese ports, meaning some of the cylinder ports are shared–specifically, this four-cylinder engine features three exhaust ports and just two intake ports. The theory behind Anton’s scatter camshafts is that there are performance gains to be had by varying valve lift, duration and lobe spacing from cylinder to cylinder. The big downside to such a complex camshaft? It’s not a cheap, easy proposition.