Home Built Oil/Air Separator (1st Prototype)

After looking at several solutions to the oil in the intercooler pipes, I decided to try several different solutions. I looked for several different types of containers and then decided to try a one quart paint can. After looking at all of the possible locations, I decided that on the firewall, next to the valve cover on the drivers side, I could get it to fit.

The first step was to reverse the vent on the valve cover. It now points toward the firewall. I removed both metal clamps on the hose between the valve cover and air intake. This allowed the hose to be pivoted on the air intake. Next was to assemble the components that would be needed. I used a one quart paint can, some sponge material, three different types of scotch brite pads, 3/4" heater hose, miscellaneous 3/4" plastic hose connectors, several 3/4" hose clamps, and one large hose clamp. I also fabricated a mount out of a fire extinguisher mount.

Next I fabricated the can. I cut holes in the top and the bottom, for the PVC connectors. On the bottom of the can, I used a 3/4" thread to female pipe connector, to get have about an inch about the bottom of the can. I screwed this connector into an elbow on the outside of the can, after using silicon sealant around the connection. I did a similar connection on the lid of the can, but cut the flange off so that the connector did not protrude into the can. I cut a couple of small squares of the scotch brite course pad to put next to the connector in the bottom of the can. I proceeded to cut the course, medium and fine pads to match the inside of the can. I also cut the sponge to fit snugly in the can.

This is the can, internal components, and lid assembly after 1200 miles.

This is the can, internal components, and lid assembly after 1200 miles. Here is a picture of the inside of the can showing the small spacer pads (one in the can, the other on the box), the connector and the oil trapped after only 1200 miles!

Unfortunately, it did not catch all of the oil. There was still some in both of the intercooler pipes. As you can see, the sponge seemed to collect the oil mainly toward the center. I modified the sponge this time by cutting it in half, moving the medium pad in between the sponge sections, and added another 3/4' sponge with a hole in the center to match the exhaust vent. I guess the first time the sponge moved up and was against the outlet opening. The sponge with the hole will act like a spacer. I then did a test fit to align the lid and the elbows before closing the can. I did not use anything extra to hold the paint can lid in place. (BTW, I have hit 27#s of boost several times !) I am also testing several different types of sponges, but I have not installed them as of the date of this article. I have some test sponges in oil and others in diesel fuel, to see if they deteriorate. 

This is the first installation. Notice the hose from the valve cover goes to the bottom of the assembly. If for some reason the oil gets over the depth of the bottom fitting, it will drain back into the valve cover. (Not ideal, but OK until the final design is made.) This is also using the stock intake port for the blow-by gasses. I am going to take a few measurements just to see how much that port draws verses moving the port to the intake box, before the air filter. Since I use a oiled-foam filter (Amsoil), I feel that this will also help keep any oil that the filter did not catch from reaching the turbo.

Already, I have planned to make several changes. I want to make a mount that will use the last two valve cover bolts to hold a frame to hold the can assembly. This will remove the assembly from the firewall, and eliminate a source of noise from the passenger compartment it will also allow the engine vibration to help separate the oil from the filter elements. Another option might be to integrate a small tube gravity drain back into the valve cover from this same location. This would eliminate any removal or need for a drainage container. There are two other changes that I will make on the next prototype. One will definitely be the sponge material. The other will be the location of the intake hose. I will make the hose come in from the side, aiming along the side of the can. This will allow the intake gases to go in a circle and hopefully this centrifugal force will help separate more oil from the air.

As a side note, most of the mileage was highway mileage, with a boost consistently from 4 to 8 #s. I have also hit 27#s of boost on several occasions. Stock engines will not have quite as much oil since the boost will be lower across the board. I also cleaned this out while replacing two bent pushrods and a broken rocker. That incident might have also contributed to the excess amount of oil.