Albertan

I'm ready to install my harmonic balancer. The oil pump has been spaced 0.125 forward for double chain. I noticed that the ID of the oil pump front cover is almost size on size with my balancer hub. I noticed the same thing with an old 5.3 engine I have as well. I am surprised that there is next to no clearance yet the old 5.3 balancer is not grooved. Is there a reason that the fit is so close? The front cover hole looks like just punched so size should be for clearance.
If it had a reason to be very close you would think it would be machined? Has anyone made the cover hole larger just for safety sake? Or has anyone ever noticed a groove in a balancer hub? Or am I the only one to ever notice this??

S10xGN

iTrader: (11)

No, no, no, and probably.

Albertan

Actually, I did a bit more inspection. Looks like if the oil pump is at its normal position the necked down part of the hub allows for clearance with the front cover. Since the oil pump is 0.125 farther out, the necked down part is now too short. The OD of the hub is about 54mm and the ID of the cover is 54.1mm,
I'm going to have my machine shop add 2mm to the front cover ID so I will have a 1mm gap. Amazing how much trouble moving the oil pump forward 0.125" causes.

S10xGN

iTrader: (11)

Didn't cause me any problems. I check my oil and cut open my filter and never see any evidence of metal from rubbing. Hey, if it feels good, do it.

Albertan

Had it machined to 56mm dia. Now when the hub fits in there is a 0.01gap all around. Probably could have just tapered the hole with inside normal and outside 56 or more. The large portion of the hub starts just before the front edge of the front cover. Just a little insurance.