Automotive Oval Air Filter

I'm so stuffed full of Turkey and ham I can hardly keep my eyes open. But I can still tell those came out great!!!

 

About to carve the bird......I'll be right there with ya shortly

Thanks David. They should clean up like the others. Rain in the forecast for the next two days then snow

Best,
Kelly

 

Sounds like a good time to start hibernation...

 

Wont shut down. With a resistive electric furnace I can melt inside but with lost foam, the pour must be outside. I can just lift the garage door to pour but I need dry pavement to demold......must keep the sand dry for lost foam.

Finished up the last two castings. Still have one more foam pattern to cast. Logo filter lid looks good.



I may have to paint one black and then sand the top surfaces back to bare aluminum to see how that looks.

Best,
Kelly

 

It's a good thought rocco. I have a tray circa 30" x 40". It has 1" sides. It's actually one of the drip pans for my automotive lift and you can see it in the pictures and videos where I stage my ingot trays. You're right though, it would be very useful especially in the Winter time when there is snow and ice to contend with on the concrete. Otherwise, the dry concrete is hard to beat.

Maybe if the pan had sides a foot tall or so it could contain a full flask. I'll still have to shovel it.......300-350lbs for a full flask. Not bad a shovel load at a time but that 30 gal barrel of sand spreads out over a big area or else it takes a long time to cool for reuse. If the sand isn't cooled, it will deform and damage the next pattern. Still even one flask a day in poor weather would be a bonus. Maybe I could c-clamp a couple trays together to accommodate more area but still be manageable and storable.......like on my automotive lift!

Best,
Kelly

 

I poured the last air filter foam pattern yesterday. It went like the others and came out well. I try to learn something with every project and iteration. On this pour, I poured quite a bit cooler than I have been (1375F). The initial hesitation seemed to be shorter but the duration of the pour was the same at about 30 seconds total. There was noticeably less black carbon residue on the surface of the casting. The picture below is exactly as it came out of the sand and water bucket.



Over my last couple projects I’ve been rethinking my typical spruing and gating strategy. Part of this was driven by the desire to cast everything in my molding rig which is essentially a modified 30-gallon drum. In the past, my preference was to sprue at the top and promote a uniform plugged progression of molten metal flow from top to bottom. Much of the typical spruing and gating guidelines (as discussed in the BiFilm thread) for sand casting don’t apply in lost foam because the evaporation and diffusion rate of foam pattern dictates the metal velocity and direction of flow more so than sprue/gate geometry. Top gating in lost foam produces a naturally pressurized system. Top gating would be generally poor practice in conventional empty cavity casting. So the diagram below is what had been my general preference………introduce metal at the top with the hopes for a plugged flow from top to bottom.



I think that’s still is ok for many parts, but the filter and the intake manifold lid have very high surface area to volume ratios so the molten metal loses heat to the mold media rapidly during the pour. The parts also have long travel distances, of 25-30” cup to the very bottom of the part resulting in relatively long pour duration times of 30 seconds or so. All of this creates higher risk of short pours so I’ve typically poured very hot (1550F-1575F!) to reduce the risk of fail…….but, I’d rather not superheat the metal, especially aluminum.

For those interested, the evolution of what I’m about to describe started here on the intake manifold lid, here.

http://forums.thehomefoundry.org/in...tive-intake-manifold-lid.366/page-2#post-7121

….and eventually evolving into this…

http://forums.thehomefoundry.org/in...ive-intake-manifold-lid.366/page-4#post-17977

On this part, the strategy was to simultaneously deliver hot metal to as much of the pattern as possible through a more massive (than the part) runner that contacted the entire length of the pattern. The sprue and runner were made from very low density (~.5-.75lb/ft3) Expanded Polystyrene (EPS). In my mind, I imagined this would cause the runner to fill first per the red arrows, and then feed the part inward per the yellow arrows. If this occurs then the runner stands little chance of freezing because it always has new hot metal running through it and the overall travel length of molten metal looks more like half the width of the part (3”) instead of the length of the part (20”).



So, I should be able to pour much cooler, and apparently I can!

Best,
Kelly

 

K & N obsoleted the filter elements I used for these air filters without a replacement. So I sourced another element that is very close in size but required a slightly larger filter gland. I used to make the patterns on my pin router but here forward they'll be cut on my cnc Router.

I was looking back on this thread. -Come a long way since I started this one.





Best,
Kelly

 

I made another variant of this filter assembly. It’s sort of a knock-on effect from K&N obsoleting the elements I used to use. K&N no longer makes any 1.5” tall filter element. They all start at 2” and go up. That extra ½” in height can cause hood interference in many of the cars that folks run these systems on. Also, though it’s not unusual for stock systems to use a 1.5” tall element, it starts to become a little iffy for allowing air to turn into the boosters for higher performance engines……..so, this iteration is a drop base filter with turning vanes in the lid that addresses those issues.

This filter is absolutely the smallest L x W dimension possible while still being symmetrical about the center of the carb. It’s actually ½” shorter in length than my previous filter and 1” wider. It uses a 2.5” tall element that is dropped 1” so the filter lid is the same height as my previous low profile filters. There is also a 3” tall element that can be interchangeably used with longer stand offs. Problem is, they are both K&N, expensive, with no other alternatives I can find and the SOBs at K&N will probably obsolete them without replacement in the future.

I had to do some minor modeling to create the 3D machining surface for the drop base.



Here are the foam patterns as they came off the CNC Router.



After a little detailing, here it is gated and ready to dip.



……and here is the finished product from the first go.



Assembled....



And new drop base variant with the previous version.



I was going to start a new thread but was looking back to the first ones I made three years ago in this thread. I’ve made quite a few refinements along the way and sort of nice to see the progression.

Best,
Kelly

 

Thanks for the comments fellas. Seems like my favorite casting is always the one I'm currently working on. I have a new intake manifold on the drawing board at the moment.

Best,
Kelly