Nissan Repair: extreme loss of oil around rear seal, rear seal, seal surface

Question
My son sent his 280z engine to the machine shop to get it into specs for optimum use. The shop put in the rear seal, Once my son got the engine back; he put it back together per instruction in the manual. When he turned the engine on oil came out in the area of the seal, also water had gotten into the engine and radiator. so he put a second set of gasket, dried out the engine pulled the tranny out, everything looked good and up to specs then bamm oil spilled out again and the second the engine ran but the oil came around the back of the engine? What do you think it is?

Answer
Destiny,

First, make sure the oil gallery plugs have been istalled on the back of the engine since they will pour oil out.  They look like allen plugs and are close to the rear main seal.  Second, you could get a micrometer and measure the seal surface area to make sure it is to specification and has not been turned down.  Too much and it will leak.  Lastly, make sure the rear seal is installed with the lip facing in.  If the spring part faces out the seal will pour oil out.

Forgot to mention that I have seen on more than one engine where the oil pump relief valve was stuck and the pressure was too much, the oil pressure needle is all the way over and off the scale when this happens.