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Can using a non vacuumed oil catch can effect the oil seals?

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Old 10-29-11, 12:14 AM
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Lightbulb Can using a non vacuumed oil catch can effect the oil seals?

Can a hose coming from the oil filler neck going into a water bottle effect the oil seals due to the lack of relieving pressure in the eccentric shaft case? My oil pressure is normal though.

I bought my t2 like this and it made me wonder if the engines pressure is high enough to relieve excess oil pressure in the eccentric shaft case without using the vacuum of the turbo?

The ex owner also gave me a real oil catch can but with only one inlet nozzle and a cap on top. Should I just connect the oil catch can and leave the cap open so it can relieve pressure or is it better to get a 2 way catch can that uses the vacuum of the turbo? I kind of dont want excess oil inside the intercooler cause it will limit the air velocity and reduce the efficiency of the intercooler due to oil excessive oil.

kind of new to turbos so any suggestions will be appreciated thanks!
Old 10-29-11, 09:43 AM
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Originally Posted by LoLsmileyFC
Can a hose coming from the oil filler neck going into a water bottle effect the oil seals due to the lack of relieving pressure in the eccentric shaft case? My oil pressure is normal though.
I don't think you're completely clear on how the oil seals work. Oil sprays out of jets in the eshaft into the back of the rotors to cool them. The oil seals have springs which scrape that oil film off the side housings. The o-rings for the oil seals keep oil from leaking past. The condition of the o-rings and springs are the most important factors.

Check out Kenichi Yamamato's 1981 book on the rotary engine https://docs.google.com/viewer?a=v&p...hOWVm&hl=en_US page 41 of the PDF. It explains the oil seals.

I bought my t2 like this and it made me wonder if the engines pressure is high enough to relieve excess oil pressure in the eccentric shaft case without using the vacuum of the turbo?
The oil pressure regulator relieves the oil pressure. Oil pressure in the forced lubrication system is not really the same thing as crankcase pressure due to combustion blowby gases.

The ex owner also gave me a real oil catch can but with only one inlet nozzle and a cap on top. Should I just connect the oil catch can and leave the cap open so it can relieve pressure or is it better to get a 2 way catch can that uses the vacuum of the turbo? I kind of dont want excess oil inside the intercooler cause it will limit the air velocity and reduce the efficiency of the intercooler due to oil excessive oil.
There are a few ways of doing it... there has been some significant discussion of this in many threads
Old 10-29-11, 01:31 PM
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no.

What you're talking about is the crank case ventilation.
The stock system re-routes this excess pressure into the intake, but it doesn't need a vacuum source to work. It is a force all on its own.

For a while I had the oil filler neck nipple and the nipple at the base of the dipstick just T together and then dump to atmosphere. No oil ever came out and it worked fine... This is how yours is set up now, except there is a bottle under it. In hindsight... I should have put some sort of filter or catch can on mine since any debris sucked in through that hole (or spiders looking for a new house) will go directly into the oil system and can ruin your engine.

Later I just routed it back to the stock location on the intake right before the turbo. If you do this, just be sure you have the stock check valve so no pressure accidentally goes from the intake back into the crank case. VERY LITTLE OIL actually comes out of this vent, plus your engine is supposed to burn oil anyway, It wont hurt anything if there is a little extra oil in your intake. (obviously... because thats how Mazda designed it)
Old 10-30-11, 11:30 AM
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Here are a few threads you can read about "crankcase ventilation" and how to properly vent your crankcase.

https://www.rx7club.com/showthread.p...se+ventilation

https://www.rx7club.com/showthread.p...se+ventilation

https://www.rx7club.com/showthread.p...se+ventilation
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