catch can on intake?
 

Anyone put a catch can on the hose from the oil cap area to the intake? My car has blown oil into the intake a couple of times now and it seems this comes up from time to time on others? Or is there a PVC valve in the works?
Olddragger

IMO if you're blowing oil into the intake you have other issues that are the cause.

I just know of too many RX-8s including mine that don't have this problem even with overfilled oil sumps.

"Normal".....
 

It's quite normal. Not good, but "normal".

I put a can on the back of the airbox, it currently has about 20mm of oil in it!

The 2007s that are coming in DO have a PCV valve on them, :eek: and in Europe there is a retro-fit kit available, completely updated vent hoses, moved the intake connection etc.

Coming soon to the US......

S

Can you please give me your source of information regarding the 2007s and the European retrofit kit?

why would some cars have the issue and other's not? Apparently there is something more at play :dunno:

I have had that problem. So far they have said it's normal.....but there is a new baffled oil pan, and the 2006's have a reworked breather system that would blow the oil into the vacuum ports on the lower intake manifold and be burnt..

I think there is a retrofit kit for the breather out there for the problem cars.

Like TeamRX8 I think that there is a problem with this....I think that excess blowby is the cause....we will see

Updated vent system.....
 

One of the threads about it in Europe.....

UK thread...

S

Has anyone actually found out the causes of the oil going back into the intake?

So hold on the catch can and wait for the new vent system--any TSB's coming?
Olddragger

:yesnod: don't flame me but the way i understand it a p.c.v. valve is known to be a positive crankcase valve something the rx8 can't use because of the fact it's a oil burner.and if you do that it would cause it to burn even more.i could be wrong but time will tell.

make that a positive crankcase ventalation valve

I have this happen as well. Seems to corrolate w/ oil overfill, but if Teamrx8 and others run it overfilled with no issues, I don't know what to make of it.

I put a catch can on, but not for oil being blown into the intake. Never had that issue, don't know how so many people could have.

Lots of people, from my searching, experienced the sludge on the dipstick issue, though. All this is caused by is condensation. Since there was no PCV system stock, I added a catch can that goes from the oil filler neck nipple to the can, back to the intake. This has effectively stopped the condensation issue and I haven't had any residue on my oil dipstick since then.

I've never had that issue either :dunno:

I didn't for a long time either, but after about 6 or 7k I started to notice it more. I thought that was kinda odd, maybe it was the weather change that helped cause it. Either way, the catch can made it dry as a bone.

hi guys,i just my understanding on catch cans, to be honest i dont know much about rotarys but i have some knowledge on doing up nissan gtr engines, which i think is similar when it comes to the p.c.v (positive crankcase ventilation valve). The the oil deposits and gases that come out of the pcv is acutally polluted, and isnt very good for it to re circulate back in the engine, so it is re fed back to the intake so it can be totally combusted in the chambers, burnt and sent out thru the exhaust . Now when it comes to catch cans, the advantage of this is that it catches all the shit and prevents it from entering the intake, which is standard on most cars in my understanding . The downside of not having one installed, is that when the fumes enter the intake it isnt clean oxygen, hence it will lower ur fuel octane when the fumes enter ur engine . Having one installed will actually increase your octane level and will help with pinging to a certain extent, also help with combustion as cleaner air enters the chamber which will increase in slightly higher hp gains , and sorry i dont have dyno figures to prove this but i would highly recomend doing so, especially if u install eg canzoomers unit to retune the car i am sure it will help , sorry for all this write up but my 2cents worth as i dont write up much :-) but i sure read alot !
Hope thats easier reading

Welcome to the forum. Try some sentence structure if you really want someone to read your post.

there is no arguement that some of the renasis engines are having blow back issues. Question is why? Dont know?
New models have new type vent systems --dont know if that will be a tsb for the older ones.
So-----anyone know of a good catch can? reasonable price? best way to hook it up?
olddragger

Could I request some pictures here of what the heck you guys are all talking about?!

What does the ventilation hose look like and where does it attach to the intake.
What does the catch can look like?

I'm a bit lost. I had a PCV valve on my Protege 5 with a ventilation hose back into the intake but I disconnected it , plugged the connector at the intake and terminated the valve cover's vent with something that looks like a small air filter. Am I hot, cold, or warm? Yeah yeah yeah... what's a valve cover...

Thanks for the schooling in advance.

Good catch can? Anything really, you can make your own fairly cheaply from Home Depot parts even. But look on ebay, shiney metal ones are abundant for cheap prices. Don't believe the lie that any of those authentic "Greddy" or "HKS" ones are any better than the 5-10 dollar ones on ebay, because they aren't. A catch can is a catch can... all it is for is to collect condensation, or in your case oil, into and nothing more.

And as far as hooking it up, and for some reference pictures for 416to212, I have some pics. I ran a line from the oil filler neck nipple, which USED to go straight into the intake, to the catch can. From there the catch can runs back to the intake. This will "pull" the condensation/oil vapor out of the neck, through the line, and into the can. The large particles of condensation/residue will stay in the can and lingering vapor will go back into the intake to be burned up in the engine.

Here are the pics, you can see my ebay catch can in between the coolant overfill and intake.

http://students.washington.edu/dreww/installed1.jpg

http://students.washington.edu/dreww/installed2.jpg

http://students.washington.edu/dreww/installed3.jpg

This is similar to what I have, but it's a different shape/size.

http://cgi.ebay.com/ebaymotors/OIL-C...QQcmdZViewItem

But really all you have to do is find the one that will work for you depending on where you want to mount it, how you want it to look, etc. I had this left over from my rx7 and just made it work, was fairly simple. They come with a couple brackets usually and from there you just have to find a place to mount it. Oh and the tubing they supply usually sucks, wont fit right, or is ugly so just go out and buy some rubber hose that will fit.

dDuB.

Thank you very much for your pictures. It has cleared up a significant amount of my confusion. However, I have one more question... Why can't we just vent into the atmosphere rather than actually catching it and sending vapours back into the intake? Besides the legal implications is there anything wrong with my suggestion. I did this on my Protege5, I can't see it being a problem in this application.

You could. The reason I even put a catch can on was to get rid of the condensation issue. Cars without a PCV system of some sort can develop condensation in the oil system. This is noticeable by a milky/sludge residue on the oil dipstick. This is what I was experiencing.

By only venting it to the atmosphere will not fix this particular problem. You need a source of vacuum to PULL the condensation OUT of the oil system and deposit it somewhere. That will then pull out all the extra oil vapor/condensation floating around and fix this issue. Venting it won't do anything.

What is the purpose even of venting straight to the atmosphere? I don't understand... If you're going to do that why not just leave it stock? There's no point in venting it straight out when you can just leave it the way it was stock. The only reason, like I said, I changed from stock was because there is NO PCV system present and I wanted a way to get the condensation out of the oil system.

I guess I just don't understand the purpose of venting it rather than leaving it hooked up... Not like it provides any gain.

where exactly on the oil dipstick would the condensed sludge show? i took a look at mine today & it appears to be sludge free... if i'm in the clear for now, would it still be a good idea to do this mod in case of future issues??

Anywhere on it, maybe more near the bottom?

It is much more common in colder times of the year and in colder areas. Being in Miami you might not have to worry ever. Example is I got my car in the spring and all through spring/summer nothing, hit fall/winter and it started showing up. But the catch can fixed it during the colder months and I haven't seen it come back since.