Inside The Wal-Mart Super Tech ST-7317 Oil Filter

I've not cut apart any other of the Wal-Mart line of filters other than the ST-7317. The main reason for this choice of filters is because this is the correct filter for many of the later VT shadow's, including the 97-2005 1100 Spirit.

The USA made ST-7317 is manufactured by "Champion" which is a main stream filter manufacture.

I hope you find the below information helpful in your next purchase of an oil filter.

Part One,

The whole filter, NEW UN-Cut!

Now with the end cut off, the USA 7317 has a heavy steel base that
seems to be VERY well attached.


Here is the inside filtering media with metal end caps. I've read reports that mentioned these filters having uneven pleats in the filtering media. This shown in this picture I don't see this as a problem. These filters also use the synthetic enhanced filtering media.


This picture shows how well the metal end-cap is attached to the filtering media. I could not pry the caps off without tearing the media just above the bonding glue. (Looked like some kind of epoxy, it is some pretty tuff stuff.)


Now the filter is torn down a little more. In this picture is the spring beneath the pressure relief valve. You can see this spring in a new filter by looking through the large center hole in the base of the filter. The pressure relief valve is made of metal with a round rubber sealing disk/pad at the top.


This picture is the top end of the filter's end cap. The black center is the black rubber pad that the pressure relief valve uses for a seal to the media's end cap. If something happens to the filter media that will not allow oil to pass through it (cloggs up), then the pressure will start to build inside the filter housing. This will apply pressure to the pressure relief valve pushing it away from the media’s metal end cap. This would allow unfiltered oil to flow by the relief valve and back into the engine. The thinking here is that dirty oil is far better than no oil!. I see no reason for this system not to work! The valve is where it's supposed to be!


Here are all the parts of the filter and the order that they go. The pressure relief valve is still mounted inside the media’s end cap although you can't see it in the picture. It's not at all like the hard plastic valve used in the Fram filters.

 
Part Two,

The Wally World Filter Part Two
I wasn't planning on going this far with the oil filter but after I got into it I decided to go on with the project. Just keep in mind that these pictures were taken after the filter was pretty much destroyed but I felt that I could use the parts for illustration. So, I used some tape to help hold some things together for the next two chapters.

This picture is of the filter base and the anti-backflow valve which doubles as a seal for the neck of the filter's in-cap. The alignment is correct. When the seal is in place its outer lip completely surrounds the smaller oil inlet holes.


This picture shows the metal suspension spring and its position on the filter's in-cap. This is the end with the pressure relief valve. The arms of the leaf spring rest in the very top of the filter's outer shell.

Part three,

Wally World Oil Filter 'The Final Chapter'.
This picture is of the entire Pressure Relief Valve 'Assembly" broken down'.
The end cap is the end that would be in the top end of the filter.


Some filter companies (Fram) uses a hard plastic pressure relief valve as a seal to the end cap and others use metal. These types of seals can let unfiltered oil flow by them. The rubber type seal used in the 7317 filter provides better sealing. This picture shows the flexing of the rubber seal in the Super Tech’s ST-7317 filter. I see nothing about the pressure relief valve in the (USA) 7317 filter that could keep it from working! The rubber disk should seal well to the metal end cap.


This picture is of the internal filter’s end-cap and a cut in half seal. This is the end of the filter that mates to the base plate. The seal doubles as a seal and an anti-backflow valve. The other half of the seal will be shown later as part of the base plate. I said that this seal doubles as a seal and a anti-backflow valve; however, its a seal between the unfiltered incoming oil and the filtered outgoing oil.  

Here is the picture of the base plate with a cut away view of the seal. If you look close you can see the outside of the seal's lip covering the filter’s oil inlet holes. That outer lip is the seal’s anti-backflow section. The incoming oil lifts/pushes the lip of the anti-backflow valve off the metal base plate to inner the filter. When oil isn't flowing into the filter the lip of the seal keeps the oil in the filter from flowing back out of the filter. The anti-backflow valve is rubber and seals against metal, both on the media’s end cap and the filter’s base plate. The center part of the seal is what seals the incoming oil from the outgoing oil. All the seal surfaces are rubber to metal. Other companies use rubber to paperboard or metal to metal. Most reports I’ve read seem to prefer the rubber to metal and none of them like the paper board end-caps that are used in some filters.( Fram)

There is a web site that shows a Super Tech filter that was destroyed in the process of removing it. They claimed it was due to the filter having a cheap light weight metal outer housing. The outer can is a little lightweight but it’s steel or at lest an alloy with steel in it. A magnet sticks very well to it. Destroying a filter taking it off from an engine is not uncommon and is usually caused by not oiling the filters gasket and by over tightening it as most of us know.

Yes, it's probably true that Wal-Mart could change the supplier of their oil filters at any time, so you might want to take it out of the box and look at the bottom of it to see if its different than what you've been using or its different than the below picture then it's made by someone else or somewhere else. Also look at the top of the filter for "Product Of USA"


I don't know if I could call the  "Product Of USA" ST-7317 the best filter made, but it’s looks to be a pretty good one and for $2.07 it's on my best buy for a filter list.

MarkC