So my 79 cutlass came with a 455 olds engine cam pistons etc built for performance

it came with a oil filter relocation kit that had the Mobil 1 301 oil filter

I have used this oil filter before on my various Land Rover discovery disco 2 I have had in the past on advise from forum members

Anyway it’s hard to find the Mobil 1 301 filters here in Canada now for some reason

so I began researching the next best thing
come to see that Mobil 1 301 has interval bypass of 30 psi

my car runs 50-60 psi when cold oil pressure and 20-50 driving around

does this mean that my oil is not getting filtered most of the time ?

What are you running for oil filters on these 455 engines with upgrades ???

 

I see the wix 51258 is a popular choice. No bypass

 

The bypass pressure number means how high the filter pressure drops needs to be before the bypass opens.

For instance, if your gauge pressure were 60 psi and the oil filter bypass were open, that means the oil pump would be putting out 90 psi.

 

1. Like Gary said the bypass only opens if there is a large restriction in the filter. It is not rated by actual only pressure.
2. I have used AC Delco filters for almost 50 years and have never had a problem with them. To be honest with you any of the name brand filters are fine.
3. Make sure you use the correct filter. A lot of the remote filters use a Ford filter. As long as you get a filter that crosses to the Mobil1 filter number it should be fine.

 

The filters mesh material needs to match the oil. Synthetic oil needs a synthetic filter.

 

51049 is more popular since it is a larger filter.

 

Is this a thing? Intuitively, it makes sense but I've never heard it before.

 

Where in the world did you see that ?

 

The 301 filter is a Ford filter so make sure whatever brand you get is for a Ford. If you get one for a 1985 Ford F250 with a 5.8L engine it should be correct.

 

The wix 51515 crosses to the Mobil 301

might try that

 

the 51258 does have a bypass. all filters have internal bypasses except some race filters like the Fram Dedicated race filters

 

[QUOTE=79cut;1656170]....it came with a oil filter relocation kit that had the Mobil 1 301 oil filter..../QUOTE]

How about a look at your relocation kit. If your set up uses a spin-on adapter in place of the original filter then the bypass valve in the factory 90° adapter housing or even the diesel filter adapter is still in play. If it has a block with female fittings in place of the factory adapter then yes, internal filter bypass is primary. This wasn't mentioned but is relevant. Good luck ~

 

[QUOTE=coldwar;1656469]thanks. I’ll have a look