A failure of the stock STI oil pan pickup has caused many engine failures due to aeration of the oil and oil starvation which destroys engine bearings, among other things if the car is not shut off promptly and not run again until repairs are made. When we saw this issue firsthand, we decided to do something about it. Here’s a failure we witnessed, in the same location as the countless others we’ve seen in pictures online. It’s about 1 CM from where the pickup tube is brazed to the flange.
Over time just from normal engine movement, vibration, and bumps in the road, the stock tube fails. When it fails, think of trying to suck soda through a straw that’s cut. Nothing comes out. No oil gets to your oil pump, oil flow and pressure stop, and carnage ensues. Some are replacing the weak section to try and resolve the issue, but that ignores a major flaw in the factory design. We decided to go a few steps further than that. After making a few different prototypes we settled on a design that we feel is very robust, while remaining affordable.
The factory pickup is essentially a tripod missing a leg. Structurally it’s a very weak design and we feel that’s a main cause of these failures. Some say the brazing process is to blame, but all the connections on the factory unit are brazed, yet they all break in one place. Where do they break? In the red area shown in this modeling image that shows the stress concentrations in the factory design. Blue areas have low stress, while red is high stress. As you can see the high stress is opposite where a third leg would be because the whole assembly after the bend is acting as a lever on that small area shown in red:
We’ve addressed this by by welding a 304 stainless bar which we bend and drill it so it meets up with a factory mounting point and clears the oil pan baffle. It serves as the third leg of the tripod and removes this huge stress concentration that results in pickup failures.
Here is the description I received to accompany the following stress analysis comparison of the OEM and OEM style design vs. a design with a third leg:
“Well, the stress in the area where we are observing failure is certainly a result of the location of the overhung load. Without a third leg to put the load within the ‘base’ of the part we are going to see a much more significant moment applied than if there were a third support. Depending on the orientation of the applied force, the area in question will have to take a significant portion of the load, combined with the short section near the flange that is available to take up that shear, we are seeing an uneven distribution of stress. While the third leg will indeed spread the stress out over a larger area, in my opinion the more significant stress reduction comes from changing the type of applied stress. You can no longer develop a significant moment there and it will be subject to compression mainly, which is a much easier to deal with and loads the stressed sections much more uniformly.”
We also replace the section known to fail with a drastically stronger material. We use a mandrel bent piece of 316 stainless steel tube to replace the weak portion of the stock pickup tube. It gets welded to the middle of the stock pickup tube where it has not been heated by the brazing process. This way we’re welding to the strongest available portion of the tube. In the pictures you can see the gap between the heated area from our welding and the heat affected area from Subaru’s original brazing of the tube to the bathtub. Then it gets welded back to the flange, all in a jig of course. Special filler rod (309L) is used since dissimilar metals are being joined via TIG welding.
As you can see, we’ve gone further than the other modified pickups on the market to make this the best affordable stock fitment unit available. On the factory unmodified unit, and the modded ones we’ve seen, the bathtub is a hanging weight that sways around and back/forth with vehicle movement and bumps, constantly pulling/pushing on the pickup tube. While the stainless tube we weld on is vastly more durable than the stock section it replaces, the third leg takes the strain off the tube so this new strong tube will experience drastically less forces on it that the stock tube. Overkill? Probably, but we didn’t want to take the most minimal approach only to see a failure and add on later.
Our modded pickup is made in a jig and test fit on an 04 STI shortblock with an oil pan to ensure fitment. It bolts to factory mounting points using the factory hardware that’s already there so no modification or additional parts are required as long as you have an 04-07 STI with a stock oil pan.
We feel that our modded stock unit is a huge improvement over stock both in design and construction, all welds are TIG’d by a certified welder, and we can offer a guarantee to repair or replace our pickup if it has a fitment issue or suffers a failure due to poor/inadequate design, materials, or construction. A violent impact, prolonged heavy vibration, or unforeseen circumstances may still damage even this beefcake pickup. Any time you have your pan off, take a look and inspect it for cracks, especially in the remaining portion of the stock pickup tube.
Alternate view:
Closeup of a weld:
As you can see our welds are not ground off to make them appear pretty or to hide imperfections. We’re proud to show them off.
Here the clearance to the pan is tested to ensure proper bathtub placement. While we’re not changing the placement from stock, some people say that once in a while a stock pickup comes from Subaru with the bathtub placed in a significantly different position. Because of this we make sure that when we’re done with our pickups, the bathtub is located properly.
Item includes new OEM o-ring.
This is a direct bolt on part. It uses factory oil pickup mounting locations and hardware that’s already there. How can this extra hole and hardware already be there? Subaru has had a few different stock pickup designs. Some mount to one side of the block and some the other, but all the blocks have both mounting points and the bolts are already there. We just use both holes instead of one. Easy as pie! Here’s an installed shot on our STI mock up block where we test fitment as part of our quality control processes.
The other places that don’t offer the third leg we add are charging more than us and our unit is strong enough that we’ve picked the whole engine up by the bathtub without the unit flexing. The competition is selling for 185 USD for a group buy price up to 250 USD without a group buy.
We did all this work to make a better unit and are only charging 150 USD. No group buy required.
I’d like to thank the engineers that aided in the design of the prototypes and Matt for all his help. I’m very happy with the way this turned out.
