I designed and built this Self-Draining Breather Tank / Turbo Oil Separator (more than a simple catch can) and thought I'd share it on Prime. I'm providing a detailed explanation of what, how and why I built this device for those who asked or would like to know.
NOTE: This basic design can also be used in non-turbo cars and serve as a COMPACT SELF-DRAINING CATCH CAN by eliminating the turbo oil inlet tube. In addition to being self-draining, other benefits include: small size and lighter weight which are made possible by its "vertical" configuration and baffle system which is more effective in draining than non-vertical configurations. One if its functions is to not "hold" blow-by oil, but to return it to the engine, thus eliminating the need to have a larger catch can that needs to be emptied.
Disclaimer: I'm just a guy that likes working on my car. I like trying different things. I've done many mods and most of them work. I hope I get "lucky" with this design and that it works as I planned. Although I'm experienced using a torch, this was a learning experience for me to be brazing thin wall stainless.
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I have a '94 with a built motor and custom twin water-cooled ball bearing turbos. The original builder didn't completely finish the job and left lots of room for improvement. I've been constantly making improvements/modifications over the past 5 years.
Ever since I picked up my car from the builder 5+ years ago, the car has burnt a quart of oil every 400 miles. The builder first told me that they suspected the turbo bearings were leaking oil or that the piston rings just needed to be broken in. After eliminating those possible causes, I suspected that the valve seals were leaking or possibly that pressure was building in the tops of the heads.
Aside from that, about 10 months ago my engine ran very low on oil. My turbos drain oil by gravity into a large (2-3 quart) oil accumulator tank that I built. A Tilton pump pumps the oil from the accumulator tank back to the oil pan. I incorporated a 1/4" air vent in the turbo oil accumulator tank to allow air to go into the tank and relieve any vacuum on the turbo bearings caused by the oil pump. The turbo oil pump actually pumps more air than oil since the oil volume discharged out of the turbos is much smaller than the pumps flow rate. What happened 10 months ago, is that the fuse to the oil pump blew, causing the pump to block the return of the turbos' oil to the oil pan. Oil filled the accumulator tank and then escaped to the atmosphere/ground through the bleeder hose.
To prevent this from happening again without my knowledge, I designed and installed an assortment of relays and a warning light and a buzzer to notify me if the oil pump (and the intercooler pump) ever loose power or ground.
That warning system will not address the problem of the accumulator tank vent, dumping into the atmosphere/ground in the event of a pump failure. I realized that if the vent would return to the engine it would prevent oil from being lost in the event of a pump failure. Additionally, under normal operation, it would be drawing air from the engine's crankcase or oil pan instead of the atmosphere. I thought it would be better to recycle the engine's air back into the engine, versus drawing external air through the vent and pumping it into the engine... then having that additional air forced to escape through the PCV valve and go somewhere for disposal. This might reduce some build up of air volume being pumped into the engine and reduce air pressure in the engine and might reduce some oil consumption. I don't like the idea of running the oily vapor into the intake to burn it because I think that oil decreases the threshold for detonation.
I decided to develop and build a multi-function device "tank" that would perform the following:
1. Improve crankcase ventilation with less restriction than a PCV valve will allow.
2. Supply the engine's air to the turbo oil accumulator tank to recycle the engine's air and reduce the volume of air (pressure) that needs to be released through the valve covers (think PCV valve). This is accomplished through the accumulator tank's 1/4" vent hose.
3. Provide a system to accept oil form the turbos and return it to the engine in the event that the turbo oil accumulator pump ever fails, thus blocking the normal passage back to the oil pan.
4. Effectively separate oil and air from the valve covers and the turbo oil pump, and return the oil to the oil pan and allow the air to escape.
5. To be light weight and small in size. Specifically to enable it to have minimal capacity through the use of a design that effectively and quickly returns any oil to the oil pan.
6. To look like Honda designed and built it. (i.e. no visible after market filter breather elements, fits into the engine bay in a natural way, etc...)
7. To be easy to check and service the filter element. No tools needed.
8. To have a filter element that discharges downward to reduce the ingestion of dust and moisture, such as if the engine were to be washed.
9. To be self-draining so that the size could be smaller and the weight will be reduced and so that all engine oil stays actively used in the engine.
10. To not interfere with anything else in the engine bay so that any other service or adjustments are easy as OEM.
I would have liked to use aluminum to construct this unit. I decided that I was not able to fabricate complex, thin and small parts in aluminum that would be as strong as stainless steel.
I chose stainless steel for added strength and thinner tubing walls for better flow.. as well as for ease of fabrication.
Here's the .025" stainless sheet that I started with:
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This is the tank starting to take shape with the 3/8" tube for the oil from the turbos' accumulator tank/oil pump.
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Here's a photo of the "sloping "V" bottom drain" designed for effective oil evacuation.
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Here's a view of the inside of the top of the unit showing the filter element chamber and the filter screen retaining door.
The crankcase filter element used.
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For oil/air separation I designed a double baffle system. Think of it as two funnels in a container, one on top of the other and separating the chamber into 3 chambers. The oil and air are dumped into the bottom chamber. Oil is drained out of the bottom chamber. During spirited driving, the oil sloshes around in the bottom chamber but it is difficult for it to get to the center of the chamber and go up through the small hole in the lower funnel/baffle. If it does, it still has to get through the upper funnel/baffle then up and over to the filter element chamber before it can escape. My baffles use steep slope angles and gravity and inertia (g forces) to keep the oil from escaping to the filter element chamber.
I tested my completed unit by filling it 1/2 full of water and shaking it as violently by hand as I could laterally. No water escaped.
Here are the baffles ready for installation. They are made of .012 stainless steel for light weight and ease of fabrication and brazing.
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This photo shows the lower baffle brazed in place and the upper baffle ready for installation.
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This is looking at the inside of the bottom of the tank with the turbo oil inlet tube on the left and the two larger breather tubes in the center.
This photo shows the filter element chamber with the hinged access door in place but without the filter element.
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Here's a photo with all brazing done.
I originally tried using a Nickel/Silver brazing rod with a melt temp of roughly 1,600 degrees F. The high heat required caused excessive distortion to the .025" stainless steel sheet. I ended using a silver brazing material with a melting temp of approximately 1,350 degrees F.
In this photo you can also see an aluminum mounting bracket that I made for the bottom mount.
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This photo shows the tank painted with Krylon krinkle paint.
The top item is a free-flowing PCV valve replacement.
The Tee on the bottom connects to the rear valve cover breather tube. The smaller 1/4" barb goes to the air vent in the turbo oil accumulator tank.
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Here's a classic shot of.... "car parts on the living room carpet".
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Here's the unit mounted in place in the engine bay.
It is waiting for OEM-type hose clamps to arrive.
This type of tank could be mounted in other locations as well.
My engine already had this vacant location available and I built the tank to fit it for appearance's sake.
Note the "Tee" installed at the far left of the photo that goes to the vent of the oil accumulator tank with temporary clamps. This would not be needed for a non-turbo application.
The tank is mounted with rubber grommets to allow for some movement and to reduce the stresses of vibration and thermal expansion.
One of my main design objectives was to have the unit look like Honda designed it and have it "fit" in the engine bay. I designed it to be at the same height as the injector cover and I painted it to match the valve covers...as I did with the water tank, cross bar, PCV valve replacement and the Methanol tank in the background.
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Here's another view of my engine bay.
It has many "goodies" and modifications that I have added. Most of them are designed to look OEM.
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To complete the installation I'm waiting for the OEM-type hose clamps to arrive.
I also need to replace an AN fitting for the oil pan. That fitting will require the removal of the Harmonic dampener. I have an ATI harmonic dampener on the way and I need to find a tool to change the dampener.
After that, It's ready for a test drive.
I estimate that it took me roughly 60 hours to design, build and install this device. I have not run the motor yet. Hope all goes well. The design is my own, however I did notice that STMPO also used a drain feature on a breather tank that was shown on Prime. I called him a couple of times and emailed pics to him. He was surprisingly helpful even thought I never bought anything from them.
Shane at Autowave, I anxiously await that ATI harmonic dampener so I can install my last oil fitting and see how this invention of mine works!
NOTE: This basic design can also be used in non-turbo cars and serve as a COMPACT SELF-DRAINING CATCH CAN by eliminating the turbo oil inlet tube. In addition to being self-draining, other benefits include: small size and lighter weight which are made possible by its "vertical" configuration and baffle system which is more effective in draining than non-vertical configurations. One if its functions is to not "hold" blow-by oil, but to return it to the engine, thus eliminating the need to have a larger catch can that needs to be emptied.
Disclaimer: I'm just a guy that likes working on my car. I like trying different things. I've done many mods and most of them work. I hope I get "lucky" with this design and that it works as I planned. Although I'm experienced using a torch, this was a learning experience for me to be brazing thin wall stainless.
I have a '94 with a built motor and custom twin water-cooled ball bearing turbos. The original builder didn't completely finish the job and left lots of room for improvement. I've been constantly making improvements/modifications over the past 5 years.
Ever since I picked up my car from the builder 5+ years ago, the car has burnt a quart of oil every 400 miles. The builder first told me that they suspected the turbo bearings were leaking oil or that the piston rings just needed to be broken in. After eliminating those possible causes, I suspected that the valve seals were leaking or possibly that pressure was building in the tops of the heads.
Aside from that, about 10 months ago my engine ran very low on oil. My turbos drain oil by gravity into a large (2-3 quart) oil accumulator tank that I built. A Tilton pump pumps the oil from the accumulator tank back to the oil pan. I incorporated a 1/4" air vent in the turbo oil accumulator tank to allow air to go into the tank and relieve any vacuum on the turbo bearings caused by the oil pump. The turbo oil pump actually pumps more air than oil since the oil volume discharged out of the turbos is much smaller than the pumps flow rate. What happened 10 months ago, is that the fuse to the oil pump blew, causing the pump to block the return of the turbos' oil to the oil pan. Oil filled the accumulator tank and then escaped to the atmosphere/ground through the bleeder hose.
To prevent this from happening again without my knowledge, I designed and installed an assortment of relays and a warning light and a buzzer to notify me if the oil pump (and the intercooler pump) ever loose power or ground.
That warning system will not address the problem of the accumulator tank vent, dumping into the atmosphere/ground in the event of a pump failure. I realized that if the vent would return to the engine it would prevent oil from being lost in the event of a pump failure. Additionally, under normal operation, it would be drawing air from the engine's crankcase or oil pan instead of the atmosphere. I thought it would be better to recycle the engine's air back into the engine, versus drawing external air through the vent and pumping it into the engine... then having that additional air forced to escape through the PCV valve and go somewhere for disposal. This might reduce some build up of air volume being pumped into the engine and reduce air pressure in the engine and might reduce some oil consumption. I don't like the idea of running the oily vapor into the intake to burn it because I think that oil decreases the threshold for detonation.
I decided to develop and build a multi-function device "tank" that would perform the following:
1. Improve crankcase ventilation with less restriction than a PCV valve will allow.
2. Supply the engine's air to the turbo oil accumulator tank to recycle the engine's air and reduce the volume of air (pressure) that needs to be released through the valve covers (think PCV valve). This is accomplished through the accumulator tank's 1/4" vent hose.
3. Provide a system to accept oil form the turbos and return it to the engine in the event that the turbo oil accumulator pump ever fails, thus blocking the normal passage back to the oil pan.
4. Effectively separate oil and air from the valve covers and the turbo oil pump, and return the oil to the oil pan and allow the air to escape.
5. To be light weight and small in size. Specifically to enable it to have minimal capacity through the use of a design that effectively and quickly returns any oil to the oil pan.
6. To look like Honda designed and built it. (i.e. no visible after market filter breather elements, fits into the engine bay in a natural way, etc...)
7. To be easy to check and service the filter element. No tools needed.
8. To have a filter element that discharges downward to reduce the ingestion of dust and moisture, such as if the engine were to be washed.
9. To be self-draining so that the size could be smaller and the weight will be reduced and so that all engine oil stays actively used in the engine.
10. To not interfere with anything else in the engine bay so that any other service or adjustments are easy as OEM.
I would have liked to use aluminum to construct this unit. I decided that I was not able to fabricate complex, thin and small parts in aluminum that would be as strong as stainless steel.
I chose stainless steel for added strength and thinner tubing walls for better flow.. as well as for ease of fabrication.
Here's the .025" stainless sheet that I started with:
This is the tank starting to take shape with the 3/8" tube for the oil from the turbos' accumulator tank/oil pump.
Here's a photo of the "sloping "V" bottom drain" designed for effective oil evacuation.
Here's a view of the inside of the top of the unit showing the filter element chamber and the filter screen retaining door.
The crankcase filter element used.
For oil/air separation I designed a double baffle system. Think of it as two funnels in a container, one on top of the other and separating the chamber into 3 chambers. The oil and air are dumped into the bottom chamber. Oil is drained out of the bottom chamber. During spirited driving, the oil sloshes around in the bottom chamber but it is difficult for it to get to the center of the chamber and go up through the small hole in the lower funnel/baffle. If it does, it still has to get through the upper funnel/baffle then up and over to the filter element chamber before it can escape. My baffles use steep slope angles and gravity and inertia (g forces) to keep the oil from escaping to the filter element chamber.
I tested my completed unit by filling it 1/2 full of water and shaking it as violently by hand as I could laterally. No water escaped.
Here are the baffles ready for installation. They are made of .012 stainless steel for light weight and ease of fabrication and brazing.
This photo shows the lower baffle brazed in place and the upper baffle ready for installation.
This is looking at the inside of the bottom of the tank with the turbo oil inlet tube on the left and the two larger breather tubes in the center.
This photo shows the filter element chamber with the hinged access door in place but without the filter element.
Here's a photo with all brazing done.
I originally tried using a Nickel/Silver brazing rod with a melt temp of roughly 1,600 degrees F. The high heat required caused excessive distortion to the .025" stainless steel sheet. I ended using a silver brazing material with a melting temp of approximately 1,350 degrees F.
In this photo you can also see an aluminum mounting bracket that I made for the bottom mount.
This photo shows the tank painted with Krylon krinkle paint.
The top item is a free-flowing PCV valve replacement.
The Tee on the bottom connects to the rear valve cover breather tube. The smaller 1/4" barb goes to the air vent in the turbo oil accumulator tank.
Here's a classic shot of.... "car parts on the living room carpet".
Here's the unit mounted in place in the engine bay.
It is waiting for OEM-type hose clamps to arrive.
This type of tank could be mounted in other locations as well.
My engine already had this vacant location available and I built the tank to fit it for appearance's sake.
Note the "Tee" installed at the far left of the photo that goes to the vent of the oil accumulator tank with temporary clamps. This would not be needed for a non-turbo application.
The tank is mounted with rubber grommets to allow for some movement and to reduce the stresses of vibration and thermal expansion.
One of my main design objectives was to have the unit look like Honda designed it and have it "fit" in the engine bay. I designed it to be at the same height as the injector cover and I painted it to match the valve covers...as I did with the water tank, cross bar, PCV valve replacement and the Methanol tank in the background.
Here's another view of my engine bay.
It has many "goodies" and modifications that I have added. Most of them are designed to look OEM.
To complete the installation I'm waiting for the OEM-type hose clamps to arrive.
I also need to replace an AN fitting for the oil pan. That fitting will require the removal of the Harmonic dampener. I have an ATI harmonic dampener on the way and I need to find a tool to change the dampener.
After that, It's ready for a test drive.
I estimate that it took me roughly 60 hours to design, build and install this device. I have not run the motor yet. Hope all goes well. The design is my own, however I did notice that STMPO also used a drain feature on a breather tank that was shown on Prime. I called him a couple of times and emailed pics to him. He was surprisingly helpful even thought I never bought anything from them.
Shane at Autowave, I anxiously await that ATI harmonic dampener so I can install my last oil fitting and see how this invention of mine works!
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