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DIY Guide: 'Full-Flow' (non-bypass) oil filter housing mod for $1. No spin-on.

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The original Porsche filter housing can be easily modified into a full-flow non-bypass design with two simple washers
(and even be superior to the Spin-on / Napa Gold 1042 combo)

We're all familiar with the spin-on adapter, but I wanted to find a cheaper and better way. At 200$ the investment is considerable for a piece of metal, be it a well-engineered one. I think it has an additional pretty big shortcoming in the tiny oil filter that comes with it. The original Porsche filter media is well over twice the size of the Napa Gold 1042 filter due to its length. In terms of flow-capacity, the larger Porsche filter media is vastly superior. I do own the spin-on adapter and ran it with a Napa Gold 1042 for a few hundred kilometers, and upon inspection I found the filter media to have partially crushed under the pressure (some of the pleats were folded on one side).

Obviously the strain on the tiny filter is pretty big. I haven't been able to find larger non-bypass spin-on filters, so figured I might as well take the Porsche housing apart and see if I could block the valve easily. I'd much rather use the original size filter for flow-capacity considerations, AND have a non-bypass situation to protect my engine in case of debris. Luckily, it's very easy and very cheap to have both, which I will show with this short guide.

Disclaimer: if you already have a spin-on adapter, don't worry because it works fine and nobody reported any major problems with it AFAIK. This guide is aimed at people who haven't gotten the adapter yet and/or don't want to shell out 200$ for one.

First let's see this valve. It's located at the bottom of your filter housing, and pulls right off with a long pair of pliers.


The device is very simple, a metal valve that slides into the plastic housing, and is held shut with a spring. The valve has two legs crimped around the spring. If the oil pressure > spring resistance, the valve opens (top-right). To avoid this, the spring has to be disabled somehow. I simply added washers to fill the space until the spring was fully compressed and thus the valve was unable to open. Illustrated here by compressing the spring:


I ended up using two of these washers, I'll measure the exact dimensions, but they were about 2 mm thick each. The prongs of the valve slide through the center and and hold the spring down tightly. It can be tricky to push down the spring all the way and at the same time get the prongs through properly. Getting the prongs of the valve through the hole of the washer sure is a tight fit. I had to squeeze them together first, then use one of those 'reverse pliers' or whatever they're called to push the prongs outwards. Some bending maybe required, and some fiddling, but it shouldn't be too difficult.


For added peace of mind, I cut a screw to size and inserted that in the middle so that the prongs of the valve can never slide off of the washer:


Pop the valve back in the bottom of your filter housing, and you're done.

IMHO this setup is slightly superior to the spin-on adaptor since it allows the use of the larger filter media with much higher flow capacity. But mostly it's just much cheaper for the DIY minded folks here :)

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Clever! Thanks for posting. 

I'm curious whether the original Porsche filter cartridge will show signs of collapsed pleats too when the time of your next  oil change has come.

Please report on that if you don't mind. 

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Moving to synthetic media in the filter affords a significant increase in flow capability. So, Fram Ultra, Royal Purple, Purolator BOSS, Amsoil EaO, Napa Platinum, & Wix XP provide full synthetic glass-fiber media that will greatly out flow the std cellulose media of the Napa Gold, Mobil-1, Bosch Distance Plus, Puro PureOne, K&N, etc. Just FYI.

Great thread on this mod, btw.

As a data point, I'm currently running a Bosch D+ on my LN screw on adapter and can report back on the condition of the media if you want (it's your thread).

Sent from my iPhone using Tapatalk

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