GM LS3 crank wheel gap/TDC relationship
Posted: Tue Dec 09, 2014 11:50 pm
Hello,
I am working on an ignition design for a carbureted LS3, and I'm trying to find the timing relationship between the gap in the crank sensor wheel (the 58x wheel) and the crank position. I saw in a couple of places the statement that the GM 58x gap "starts at 30 deg ATDC of cyl 1", but in looking at the LS3 I have on the stand, that does not seem to be correct. If I turn the crank by hand, the leading edge of the gap (i.e. where the last tooth trailing edge starts) is about 5 BTDC for cyl 3 (the last cylinder in the sequence), or 95 deg BTDC of #1. The gap ends at 80 deg BTDC #1, so it is about 15 deg wide. I can't seem to reconcile this discrepancy. Does anyone know what the gap AT THE SENSOR relationship to TDC #1 is?
Thanks,
Dave T.
I am working on an ignition design for a carbureted LS3, and I'm trying to find the timing relationship between the gap in the crank sensor wheel (the 58x wheel) and the crank position. I saw in a couple of places the statement that the GM 58x gap "starts at 30 deg ATDC of cyl 1", but in looking at the LS3 I have on the stand, that does not seem to be correct. If I turn the crank by hand, the leading edge of the gap (i.e. where the last tooth trailing edge starts) is about 5 BTDC for cyl 3 (the last cylinder in the sequence), or 95 deg BTDC of #1. The gap ends at 80 deg BTDC #1, so it is about 15 deg wide. I can't seem to reconcile this discrepancy. Does anyone know what the gap AT THE SENSOR relationship to TDC #1 is?
Thanks,
Dave T.