putting my motor back together i noticed there is a verticle bolt that is like 19mm that is on my water pump. whats it for?

 

oil pump? or water pump? got a pic?

 

oil pump, its a bolt that the head of it is pointed stright twards the hood.

 

I'm pretty sure there is a spring inside. Can't remember if it is a check valve or bypass. I have an old one if needed.

 

thanks, just wondering what it was, i've got a couple of them laying around.

 

If its what I'm thinking of, then it's the oil pressure regulator. The spring applies pressure to a small piston and that's what regulates the oil pressure itself. I've shimmed them in the past on certain engine builds where internal assemblies were altered (simply put).

 

i believe its a "OIL" pressURE relief valve.