positive crankcase ventilation (PCV) system were also early forms of emissions control. The camshaft gear was also made slightly stronger by using steel with nylon teeth instead of being completely made from nylon as on previous ones. Aftermarket steel, aluminium, and alloy gears have been produced as replacements to prevent the gear from stripping its teeth: this is commonly due to overheating causing the nylon to weaken. This is one of the two major weak points of the Essex V-engines, the other being the hexagonal oil pump spindle / shaft which can round off, or even break. The 2.5 L engine was rated at SAE gross or DIN and peak torque was rated at SAE gross or DIN. The 2.5-litre version ended production in 1977 along with the Essex V4 engine. The V6 engine as used in the Ford Capri RS 3100 was essentially a 3.0 L engine bored out by or 60 thousands of an inch from to . It was capable of at 5000 rpm and of torque at 3000 rpm. It featured blue rocker covers in order to distinguish the engine from the usual 3.0 L engine and it also featured hand-polished and ported inlet and exhaust ports. Only 250 RS 3100s were produced for homologation purposes, making original 3.1-litre engines very rare, although modified engines bored +0.60 are common, one of the first 50 engines which was in a RS 3100 that was free for car magazines to review and test in fact had instead of the of the rest of road going RS 3100s, this was achieved with a higher lift camshaft. These figures vary somewhat depending on the source. The Essex V6 also formed the base for the 3.4 L Cosworth GAA born in May 1972 and designed by Mike Hall, also responsible for designing Cosworth's famous DFV Engine. The GAA had the benefit of bores, DOHC aluminium alloy heads, Lucas mechanical fuel injection, a dry sump oiling system and a steel crankshaft and generated at 9,000 rpm and of torque. Mike Hall's intention was to design the cylinder heads so that 3 spark plugs per cylinder could be fitted, but this idea was dropped since there was no appreciable increase in power or torque. The original objective was an engine with a minimum of ; this objective was exceeded, with the engine making in the first test run. This engine was used in