Oil pump idler gear placement

[monkeyy337]

I finally got the high volume oil pump gear out of the motor but when I removed the oil pump cover plate the idler gear fell out and I didn't see which way the gear was facing in the pump. There is a small square (I don't know how else to explain it) on one side of the gear flat side surface and I don't know if it should face the engine side (top) or the bottom side (oil filter) direction or if it matters. I also have no idea why the square is machine into the gear or what its function is. The motor is a 231 Buick V6. Thanks for any info.

 

[WarWagon]

That is a position indicator, I always made it face up wards toward the distributor. And is something is off you should be able to tell which side was facing down with the wear shown on that edge of the gear.

 

[monkeyy337]

I've got another question if anyone could help? I know how to measure the end play on the oil pump gears but what keeps the gears from just falling down against the end plate when the motor is running. The only thing I can figure is a film of oil that is on the end plate or is it the way the gears are cut that makes them ride up when the motor is running. It sure is easier working on a Chevy motor but guess thats what makes a Buick unique.

 

[charlief1]

Read this and it should help you some.

How to build a front cover/oil pump - TurboBuicks.com

 

[WarWagon]

The pump gears ride against the filter adaptor on a thin film, so yeah they are riding right on the cover and they leave wear.