or should I replace it. The grooves aren't real deep, but there are plenty of them, and the "how to rebuild your nissan/datsun ohc engine' book says 'If your fingernail goes bumpety bump, better get a new pump'

I don't know what would be considered excessive wear or how exactly the oil pump does it's job but it does look like your fingernail would go "bumpity-bump" over those ridges.

Due to the importance of the oil pump and that they're reasonably priced, consider getting a new one to eliminate all doubt.

Good luck with your car.

That pump is shot. Replace it and change the oil and filter.

That pump is shot. Replace it and change the oil and filter.

I'd have to agree.

thanks

I'm actually in the middle of a comlete rebuild, so oil and filter change are the least of my worries.

If you are doing a complete rebuild don't even think about using the old oil pump. As has been stated above they are not that expensive to risk the rest of your investment.

thanks

I'm actually in the middle of a comlete rebuild, so oil and filter change are the least of my worries.

I was actually agreeing with the 'shot' part. The oil and filter are a no-brainer.