The standard system on many 848, 948, 998 and 1098cc engines is a single chain drive between the crank and cam. This chain will stretch with use and throw out the cam timing causing noticeable power loss.

The ‘S’ and some 1275 models have a much better ‘duplex’ chain, but even these do wear out. The best way to judge wear is to check the chain while you are taking it apart. With the timing cover off, rotate the crank a slight amount back and forth. The camshaft must move the exact distance at the same instance.

Timing scatter induced by the standard set up can reach up to 15-degrees once the single row chain has stretched, which it does after only a few miles. This scatter not only affects the cam timing, but also the ignition and the distributor, since it is driven by the camshaft. Power loss suffered by this phenomenon is substantial.

On road use cars replacing the standard single row (simplex) system with this dual row (duplex) system greatly reduces the problem (for racecars a fully adjustable version is available).

Part number C-AJJ3325EVO includes an ultra-light non-adjustable steel duplex timing gears with lock tab and countersunk screws and a 2H4905EVO limited stretch race quality chain with a retail price of £75.80 inc VAT.

For more details visit 01707 607 700 or visit ENDS.