Hi Dave, yes the crank does make 2 full revolutions to one of the cam. My issue is that when the CAM timing mark is positioned towards the crank, the inlet and out let valves should be closed in order to set timing at # 1 piston TDC. I'm have never seen this on a cam where you cant set your timing on number 1 piston TDC and timing marks dot to dot. When you aligned the timing marks on this cam, its actually TDC on number 6 and inlet about to open on number 1, if that makes any sense .To set the timing on #1 piston TDC, you have to rotate the cam 180 deg. Again I have never seen this before.
Hi Tony, I get exactly where you are coming from.
As Dr Terry has informed us, many engines are like this, incl the small block chevy.
Probably explains why many home mechanics, including myself, have swapped over the cam in a Holden red 6, installed the distributor to fire cyl #1, put the rest of the engine back together and then found the engine was backfiring out the carby.
Edited by S pack, 16 August 2018 - 11:24 AM.