Packard Forum Index » V-8 (1955-56)

Hello Everyone,
A while back I noticed my lines to and from the oil filter canister are reversed. The supply line runs from the cylinder head to the bottom of the canister and the return line runs from the top of the canister to the fitting next to the oil filler tube. This current set up means the oil filter is filtering the oil from the inside out. Probably not very efficient. My real concern about this setup is that when you shut down the engine and the oil drains back into the engine it back flushes the filter back into the engine. Not good. I am going to bend some new lines to get the oil flowing in the right direction. One of the 90 degree fittings on the filter housing has a restriction built in. Is this restriction necessary or was it someone's attempt to create more back pressure and stop the oil starvation Packard was dealing with or is it to reduce the pressure in the filter canister? As you can see, this restriction really cuts down on the amount of oil flowing into the filter.

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Some restriction is necessary but since the V8 filter oil is supplied from a different spot than on inline 8s it is not as critical. On V8 filters I believe the restriction is in the center pipe. On some there is a small outlet hole -- maybe 3/32" in diameter -- approx 2" from the top of the pipe. On others there are two or three very small holes spaced down the length of pipe. Those should be the only restrictions necessary. If the restriction in the fitting is larger than the holes in the pipe then it won't hurt to leave it.

On the inline 8s the restriction is more critical because the oil supply is taken to the filter before it reaches the valve lifters. On those engines, without the restriction the hydraulic lifters can be starved for oil if too much goes to the filter whereas on a V8, the filter supply is taken from a point after the lifters get their supply.

The early inline 8s had the restriction in the fitting so perhaps someone had an extra fitting or read one of the early bulletins and decided to make a restriction in that car. Perhaps the car had noisy lifters from one of the oil pump issues and that restriction was an effort to control a different problem.

Thanks for that information Howard. Something I forgot to mention was that I performed an oil pressure test with and with out the restricted fitting and there was no change in pressure. I took the reading by removing the oil pressure sending unit and installed a gauge. Both readings were 48 at idle and 60 at high RPM. I have the Oldsmobile oil pump installed. I think I will bend some new lines and remove the restrictive fitting. If I blow the gaskets on the filter housing I will put the restricted fitting back in. Thank you again. Brian