Fitment of an uprated cam drive system is essential when building a performance oriented engine. Timing scatter induced by the standard set up can reach up to 15degrees 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, the distributor being driven by the camshaft. Power loss suffered by this phenomenon is substantial. Replacing the standard single row (simplex) system with a dual row (duplex) system greatly reduces the problem, use of a toothed belt system all but eliminates it. The belt system vastly reduces valve train noise and also helps damp out some of the odd harmonics generated by the 3 main bearing 'A' series engine. It is also extremely important to time any cam in to it's required setting to obtain maximum performance, especially with performance cams. The 'dot to dot' method can, because of manufacturing tolerances, be out by as much as 15degrees. Anything above 2degrees out and power suffers-most noticeably in small bore engines. In race engines you probably lose 1 hp for every degree the cam is out, more when over 6degrees! Technical Note:
CONTENTS:-
PART NUMBER DESCRIPTION QUANTITY
C-AEG578 Camshaft sprocket, lightened 1
AEA695 Crankshaft sprocket 1
2H4905 Timing chain 1
AEA687 Screw - countersunk 2
The front plate will have to be countersunk as shown ‘X’ to take the screws AEA687, which replace the existing hexagon-headed screws, which would foul on the timing chain. Check for clearance on chain all round and align gears as per Workshop Manual.
When using ‘A’ plus timing covers there is a small round pressing at the bottom which needs making flat to allow timing chain clearance.
Ensure that the crankshaft oil thrower 12A1148 is correctly fitted with the letter F. Facing you or on very early engines the lip faces outwards.
Fitment of an uprated cam drive system is essential when building a performance oriented engine. Timing scatter induced by the standard set up can reach up to 15degrees 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, the distributor being driven by the camshaft. Power loss suffered by this phenomenon is substantial. Replacing the standard single row (simplex) system with a dual row (duplex) system greatly reduces the problem, use of a toothed belt system all but eliminates it. The belt system vastly reduces valve train noise and also helps damp out some of the odd harmonics generated by the 3 main bearing 'A' series engine. It is also extremely important to time any cam in to it's required setting to obtain maximum performance, especially with performance cams. The 'dot to dot' method can, because of manufacturing tolerances, be out by as much as 15degrees. Anything above 2degrees out and power suffers-most noticeably in small bore engines. In race engines you probably lose 1 hp for every degree the cam is out, more when over 6degrees! Technical Note:
CONTENTS:-
PART NUMBER DESCRIPTION QUANTITY
C-AEG578 Camshaft sprocket, lightened 1
AEA695 Crankshaft sprocket 1
2H4905 Timing chain 1
AEA687 Screw - countersunk 2
The front plate will have to be countersunk as shown ‘X’ to take the screws AEA687, which replace the existing hexagon-headed screws, which would foul on the timing chain. Check for clearance on chain all round and align gears as per Workshop Manual.
When using ‘A’ plus timing covers there is a small round pressing at the bottom which needs making flat to allow timing chain clearance.
Ensure that the crankshaft oil thrower 12A1148 is correctly fitted with the letter F. Facing you or on very early engines the lip faces outwards.
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