LJ78 PCV to Catch Can to Atmosphere? (1 Viewer)

[Jonesey]

I realize this has been discussed in various threads over the years and I'm sure it likely has a thread of its own somewhere. Because I'm not finding exactly what I'm looking for, I'm starting this.

I have done various mods to my '91 LJ78 that have been discussed at length on here: EGR delete, air-air intercooler (kept my A/C, 3" core mounted a bit low in front of condenser, routed aluminum intercooler pipe through hole cut into fender well), 2.5" exhaust turbo-back, catch can going from PCV.

For PCV: I was routing to catch can then back into intake hose, but was still noticing oil blow-by / build up around throttle body, plunger that used to be hooked up to EGR system...was dripping oil all down passenger side of engine, onto starter, down to frame rail. In attempt to rule out turbo seals, I have now vented from PCV to catch can to atmosphere - spitting out just above frame rail. I do see oil dripping from hose vented to atmosphere, even with catch can still installed - meaning, catch can is not catching everything.

Note: I did put a silicone vacuum cap over the intake port that PCV vent hose used to go to - I SHOULD cap that off, correct?

My main question: any ill effects of venting to atmosphere for a prolonged period of time? Looking to hear from those of you who have vented to atmosphere for years...and if you have any lessons learned from that. No issues / damage to engine because air is now circulating a different way / no longer through intake? Thoughts on keeping catch can even though I'm venting to atmosphere? Is it OK to keep this? I don't mind emptying it from time to time. I do top my oil up every week or two as I'm losing some in this vent-to-atmosphere scenario.

If this cuts down on oily throttle body/engine and is 100% safe, I'm all for keeping it this way.

Thanks for reading and look forward to input.

 

[Houser]

If you have deleted your egr you really dont need to worry about getting oil in your intake. With no soot entering your intake there is nothing for the oil to sludge up.
If oil is getting into the intake with the crank case vented to the air its most likely coming from the turbo. Those ct-20s are kinda bad that way. It took me 3 tries to get one that
Didn't blow oil. Also, a dirty air filter will make the turbo blow oil. The extra vacuum
Makes the seal leak.

 

[JuanJ]

Hello,

Atmosphere ventilation may not be legal in some places, emissions wise. Crankcase ventilation to the intake duct exists for a reason.

Make sure your ventilation piping is either capped or routed to the air intake. Crankcase ventilation does not produce as much intake sludge as EGR does.







Juan

 

[GTSSportCoupe]

The oil mist will build-up in the intercooler over time, so you need to either use good catch can or vent to atmosphere.

I've heard that venting to intake is good, as the vacuum draws stuff from the crank case and reduces pressure on oil seals etc.

I just do atmosphere like the old diesels.

 

[Jonesey]

Thank you all for your input.

@GTSSportCoupe That's what I was getting at, wondering if venting to atmosphere might have a negative impact on oil seals or turbo seals because of change in vacuum... but you've been venting to atmosphere for quite some time, correct?

Have you noticed any oil seal or turbo issues since routing to atmosphere? I'm currently going to catch can (a Mishimoto one) and then to atmosphere from the can. I do like that things are cleaner intake side, but just wondering if I should be anticipating other issues with turbo or other oil seals when doing this long term.

 

[GTSSportCoupe]

Thank you all for your input.

@GTSSportCoupe That's what I was getting at, wondering if venting to atmosphere might have a negative impact on oil seals or turbo seals because of change in vacuum... but you've been venting to atmosphere for quite some time, correct?

Have you noticed any oil seal or turbo issues since routing to atmosphere? I'm currently going to catch can (a Mishimoto one) and then to atmosphere from the can. I do like that things are cleaner intake side, but just wondering if I should be anticipating other issues with turbo or other oil seals when doing this long term.

I've been venting for 10 years and no problems from what I can tell. Note the later 2L/3L valve covers are improved and blow less mist. I bought a brand new one and it seemed to improve things.

 

[Houser]

I was using a catch can but changed to this simpler method to reduce clutter. In this photo you can see the dark area in the vent hose. The oil only climbs a few inches up the hose then drains back into the valve cover. Also I installed a drain petcock on the bottom of the intercooler to drain off any oil that might collect. I checked after about 2000 Kms and so far no oil has collected.

 

[GTSSportCoupe]

I was using a catch can but changed to this simpler method to reduce clutter. In this photo you can see the dark area in the vent hose. The oil only climbs a few inches up the hose then drains back into the valve cover. Also I installed a drain petcock on the bottom of the intercooler to drain off any oil that might collect. I checked after about 2000 Kms and so far no oil has collected.

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View attachment 3399182

That's really excellent. Thanks for the pictures. I really like the work you do and your contributions here. I run my breather hose up high for same reason, but maybe will also try back to intake and a intercooler drain.

 

[Jonesey]

This is great you guys, yes, thanks Houser for sharing the photos. I'm going to make some adjustments, as well. Putting in that high loop is brilliant. I initially just did a catch can and routed back to intake after installing intercooler, thinking I was protecting intercooler with catch can, but then noticed things were still quite oily around throttle body. Considering catch can doesn't catch all and I ran that way for a couple months, I likely have some oil in intercooler now. Drain idea is great - thanks. I'll post some photos of my air-air intercooler setup in a new thread sometime soon.

Houser - our LJ78's share the same color combo, that's cool. My paint is flaking/peeling on hood, but is overall in OK shape for being what I think to be original...I kind of like the rough-around-the-edges look.

 

[Houser]

Yea the hood on mine looks like it has had a paint over. It probably had some sun damage that needed fixing before it went to auction. Most of the really nice looking land cruisers that are shipped to the states have had a paint over.

 

[Houser]

If your still getting a lot of oil leaking from your intake manifold gasket you might need a new gasket. The factory gasket is just a thin metal foil and the surfaces need to be perfect for it to seal. Its ok to use RTV.
I use the grey stuff it sets fast.