Oil Pressure Question

[Nate]

Hello Everyone,
I have rebuilt a 305E and it is on the engine stand, It has a 5 qt. pan. I installed a kit in the oil pump and it appeared to have good flow when I tested it in a pan of oil. I have the pump on the engine, oil pan installed and engine filled to proper level . I have installed a temporary gauge and run the oil pump shaft (clock wise) with a drill. I get good flow at the oil pressure fitting but when I connect the gauge (new mechanical gauge) it will not build pressure. My question:
Is it necessary for the engine to be rotating to build pressure or does it seem that I just have a bad oil pump?

Any help would be appreciated.
Nate
Southeast Kansas

[BarryGMC]

Not knowing anything about this engine, I will hazard a guess. Oil pump pressure relief valve is assembled wrong or missing or maybe stuck open. ?????

[Nate]

Thanks Barry,

It must have been the relief stuck open or air locked, I took the spin on oil filter off and turned the pump with a drill and it pumped out a good flow in a bucket, replaced the filter and it pumped up to 60psi, I guess that I will go with it but watch oil pickup pressure closely after a oil change.

[Foley]

Nate, you mentioned taking off the spin on oil filter. Did you initially change out the cannister oil filter housing to a spin on? If so, where'd you find one? Tks

[Nate]

The engine had the spin on filter when I bought it, the housing has a GMC logo on it and the number 2481665, I do not know if this is a GMC part number or a casting number. I hope this helps you.

[Nate]

I just noticed that Jeannie has a excellent picture album of spin on oil filter housings, very informative, way to go Jeannie!

[Foley]

Yup, there are three albums posted. It's been a big help to be able to look at all those pictures. I was wishing it would say what companies made them. Hoping to find a lead as to where I could purchase one. Thank you Nate for the part number off your housing.

[705jmguy]

hi nate

would like to know where u got the main crank bearings and rod bearing for your rebuilt 305?
thanks Jm





OTE=Nate;50547]Hello Everyone,
I have rebuilt a 305E and it is on the engine stand, It has a 5 qt. pan. I installed a kit in the oil pump and it appeared to have good flow when I tested it in a pan of oil. I have the pump on the engine, oil pan installed and engine filled to proper level . I have installed a temporary gauge and run the oil pump shaft (clock wise) with a drill. I get good flow at the oil pressure fitting but when I connect the gauge (new mechanical gauge) it will not build pressure. My question:
Is it necessary for the engine to be rotating to build pressure or does it seem that I just have a bad oil pump?

Any help would be appreciated.
Nate
Southeast Kansas[/QUOTE]

[Nate]

Hi jm
The main bearings I got from Kanter Auto Products, they are a Michigan Engine Bearing MBS 2521.std. The rod bearings my machinist got from goenginepro.com and they were a Sealed Power brand, part number 2400P I looked on Rockauto web site and they also have the Sealed Power 2400P rod bearings, but do list main bearings for the 305E. The rod bearings were also std.

[705jmguy]

good morning Nate

thank you so much for your prompt reply, and for the info

as you did not need over size, I would assume that your crankshaft measured out as ok?

thanks again JM

[Nate]

Hello jm

Yes the crank was good, the cylinder walls were water damaged due to the engine being vandalized before I purchased the truck, the engine was seized with severe rust and still had water standing in 2 cylinders. It was a test of patience to get the engine disassembled.
I have been told that if you have the crank turned it needs to be heat treated afterwards, I did not pursue this as machining was not needed.