Good morning ! Having recently acquired an A7 long stroke in big lumps, the engine reported to have been partially rebuilt, I decided to have a look inside anyway as the previous owner couldn't give a guarantee that the sludge trap had been cleaned out. (couldn't remember as the machining had been done 50 years ago) On inspection I found all clear with the crank except that the con rod bolts hadn't been torqued down evenly. And the piston ring gaps too big. The crank had been reground, barrel had been re-bored and a new can shaft fitted. Proceding with caution, on re-assembly I found a selection of timing gears(just over two complete sets) the two camshaft pinion key ways different in relationship to the position of the breather timing peg and the crankshaft pinions timing marks differ by one tooth. Anyway, having played around with the timing gears the best I can come up with (using a dial gauge, set over each tappet and a degree disc on the crank shaft) are as follows:
Left cylinder: Inlet Opening - 18 degrees BTDC
Inlet Closing - 70 degrees ABDC
Ex Opening - 60 degrees BBDC
Ex Closing - 22 degrees ATDC
Right cylinder: Inlet Opening - 18 degrees BTDC
Inlet Closing - 75 degrees ATDC
Ex Opening - 65 degrees BBDC
EX Closing - 25 degrees ATDC
Is there anyone out there who can throw some light on these readings as they don't seem to conform to any of the cams listed in the service sheets. Having asked the previous owner if he was sure it was a long stroke cam that he fitted, he told me that ' they looked the same' and that the old, worn camshaft had been discarded. There are no numbers or markings on the new camshaft. Any help or pointers would be much appreciated. Thankyou in anticipation.
