2f pcv valve purposely blocked (1 Viewer)

[cbthompson14]

Have a 78 with the 2f. I think it’s been Desmogged as I’ve been looking at some of the vacuum hoses. One thing I noticed is the Pcv valve hose is cut and has a bolt plugging it. The intake manifold where I think the original hose should already has a hose routed which appears to go to the desmoggimg system (holding the hose in the last picture) Any clues why this hooked up this way?

 

[hobbes]

Where does the other end of the hard line go? Charcoal canister?

Have you run the engine much?

Seems like the PCV valve is still there in the factory location. You can jiggle it to see if it still works (p/n 12204-51012). Be careful pulling it out. The rubber grommet gets brittle and can pieces can easily fall into the engine. If the grommet is brittle, it should be carefully removed and replaced with new OEM (90480-18180).

Only reason I can think to block one is to temporarily mask the amount of blow-by. The crank pressure needs to go someplace.

 

[cbthompson14]

Where does the other end of the hard line go? Charcoal canister?

Have you run the engine much?

Seems like the PCV valve is still there in the factory location. You can jiggle it to see if it still works (p/n 12204-51012). Be careful pulling it out. The rubber grommet gets brittle and can pieces can easily fall into the engine. If the grommet is brittle, it should be carefully removed and replaced with new OEM (90480-18180).

Only reason I can think to block one is to temporarily mask the amount of blow-by. The crank pressure needs to go someplace.

The hardline does go to the charcoal canister from what I can tell which doesn’t match some of the drawings I’ve seen. But the line looks like it might be factory?

I’m helping my dad out with this. He’s had it about a year and hasn’t noticed any problems really with the engine. I noticed it as we were looking at coolant lines to add back in the rear heater. I know the carb has been replaced but still not sure why the pcv like would be blocked off. Should I replace the valve and just the line open, as in remove the bolt from the line ?

 

[hobbes]

Pull the valve out and jiggle it. If you hear a noise the valve is ok. You can run the truck without connecting the line to anything. Maybe put a small filter on the end. See how much smoke come out the tube. That will indicate how much ring blow-by the truck has. Maybe they were worried about fouling the plugs with excess oil going into the intake…

You either want to route the PCV correctly or have it vent to the atmosphere. If it’s plugged, the excess crank pressure will find other ways out of the engine and cause oil leaks.

It does look like someone connected the EVAP line to where the PCV should go, but I’m not positive. Someone will be along and know for sure. The EVAP line should go through a VSV, which probably broke long ago.

TOYOTA LAND CRUISER 40 55FJ40LV-KCJA - TOOL-ENGINE-FUEL - VENTILATION HOSE | Japan Parts EU

TOYOTA LAND CRUISER 40 55FJ40LV-KCJA , VENTILATION HOSE

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[65swb45]

Do some searches on how to properly reconnect this and do it sooner than later. Tell your dad that he is a lucky man.
I have a very vivid memory to this day of breaking the curfew after the Rodney King riots to visit a client in the barrio who had blown up his engine after a barrio ‘desmog.’ The PCV was capped, and the resulting pressure blew the rear main seal out of his engine on the freeway. Ran it out of oil before he could get off the highway.

 

[cbthompson14]

Currently we’ve put a filter on the end, and we have ordered a new grommet and pcv valve to install. I’m still confused why then like from the charcoal canister is going to the intake manifold spot. I have found that the erg has an open spot where vacuum hose should hook up on the port pointing towards the firewall and wonder if that is where the line should be routed instead. Current temp fix is the picture now.

 

[65swb45]

What research led you to that result? Did you pull the old valve to see if the ball rattles?

 

[B y r o n]

In general PCV hoses generally are routed to the air cleaner housing. This allows the blow by to be filtered before being burned. Sort of the same for the charcoal canister, it gets routed to where fuel vapor can be burned instead of just venting to the atmosphere.

 

[pb4ugo]

Most positve crankcase ventilation(pcv) systems I've seen are routed to manifold vacuum and the valve regulates the gases according to manifold vacuum. It's air intake to the crankcase is routed thru the air cleaner or has a separate filter so it has filtered air going into the engine.

 

[Malleus]

Currently we’ve put a filter on the end, and we have ordered a new grommet and pcv valve to install. I’m still confused why then like from the charcoal canister is going to the intake manifold spot. I have found that the erg has an open spot where vacuum hose should hook up on the port pointing towards the firewall and wonder if that is where the line should be routed instead. Current temp fix is the picture now.

View attachment 3297237

If I was going to do this, I'd do what the 80 guys are doing. The idea that you can filter the overpressure air from the valve train with the air filter may have been a holdover from the old wet filters, but there's a better way. If you separate the oil from the overpressure air completely, it never gets into the intake. The PCV exhaust needs to be filtered before it goes into the intake, or else you're contaminating the fuel/air mixture with oil, and that won't burn. The 2F doesn't have the same problem with this that the 1FZ-FE does, obviously, but the result is still the same: oil in the fuel/air stream.

 

[pb4ugo]

Generally the line from the charcoal canister is run to the air cleaner or a carb vent so the gas fumes are sucked into the carb. There's usually no liquid present. If you have a lot of blowby or liquid oil from the PCV @Malleus idea sounds good. You have to remember to drain the catch can. I've also seen folks with a lot of blowby run the pcv hose out the back of the vehicle and let it vent/smoke. Blowby is usually from bad rings.

 

[middlecalf]

… but there's a better way. If you separate the oil from the overpressure air completely, it never gets into the intake. The PCV exhaust needs to be filtered before it goes into the intake, or else you're contaminating the fuel/air mixture with oil, and that won't burn.

I put one of these in my F135. Definitely works (collects oil in blowby). Some debate as to legality for places with emissions mafia.

Choose Your Catch Can

www.eliteengineeringusa.com

 

[cbthompson14]

Most positve crankcase ventilation(pcv) systems I've seen are routed to manifold vacuum and the valve regulates the gases according to manifold vacuum. It's air intake to the crankcase is routed thru the air cleaner or has a separate filter so it has filtered air going into the engine.

I think this is how the 2f is done from the factory.