Catch Can

[quietpeen]

Wonder why they put it right into the throttle body on the ram but on the chargers they put it after

 

[JohnnyDollar]

Wonder why they put it right into the throttle body on the ram but on the chargers they put it after

Who knows.

The charger looks like the throttle body faces forward to the air cleaner.
My RAM has the air filter on the left rear of the engine and the air flows from the top, the throttle body faces up.

 

[JohnnyDollar]

I can only guess that gravity pulling the air down, increases the flow and thus increases the power.
lol


I just made myself LOL IRL.

 

[quietpeen]

Lol

 

[3 G Bee]

I wasn't going to say anything because catch cans are not the hill I want to even fight on.

I am no car/engine guru,
but I am old enough to remember owning cars that simply vented the PVC gases out into the atmosphere and oil dripped onto the street.
That is a big no-no these days, so my understanding is that it is piped back into the engine for environmental reasons.

I have one on my 2012 Ram 1500 5.7L pickup, and I may be wrong, but I think it helps two things.
1) on my truck the PCV line goes directly into the throttle body, so it seems to keep the throttle body cleaner.
-perhaps that is just my imagination.

2) My understanding is that introducing a fine mist of oil into the fuel will lower the octane rating.
I have often wondered if this is the reason that my owners manual recommends using 89 octane (midrange) gas vs. regular 87 octane to prevent knock, especially when towing.
I have always run a catch can on this truck, and always used regular and mostly use the truck for towing our boat and have never experienced any knock.


Actually, over on the RAM forum, someone forgot to empty their catch can, it filled up and his truck simply died.
He emptied the can, and was on his way. It did not cause any major disruption. He said it was mostly embarrassing.

My own experience early on was that I was afraid to over-tighten it, the bottom part unscrewed itself, fell off and my CEL came on.
I looked under the hood and found the catch can wedged between the frame and some wiring...
I screwed it back on and was on my way.



This makes it sound like installing a catch can is actually detrimental to the health of the engine, robbing it of vital lubrication.

Part 1
I am not here to fight or argue with anyone and much to old to want to climb any hills, but the evolution of engine emissions and the purpose of preventive technology is the discussion I will attempt to explain and why I believe catch cans not only harm your engine but could potentially put you in harm.
Since you are old enough to remember oil dripping onto roads from car engines you should remember Draft Tubes. This was the first kick at the can. PUN INTENDED.
Draft tubes were metal tubes installed high up on engine blocks / heads and vented back into intake manifolds breathers for the purpose of returning unburnt hydrocarbons preventing smog.
This did not work on all engines and in fact created a problem during WW2 where Tank engines filled with water through the draft tubes when tanks were forging through wetlands

In early 60's the PCV was place in all California vehicles however they also created a problem and the oil that was dripping on the roads was actually caused by inadequate oil supply which cause engines to blow out head intake valve cover gaskets creating the leaks.

By mid to late 60's all US cars were required to have smog protection and PCV became standard equipment which soon spread across the globe. To prevent not only emissions but was claimed it helped engine internal cleanliness and oil lifespan This bears repeating HELP CLEAN INTERNAL ENGINE AND EXTEND OIL LIFESPAN

In order for the PCV to sweep fumes out of the crankcase it must have a source of fresh air / clean air must enter through what was called a crankcase breather which today is ducted to the engine air cleaner or AIR INTAKE.

In older engines you will recall was simply a breather cap on top of the valve cover. This cap was to prevent the oil mist fumes from fouling the carb air filter. however required replacement quite often. do to oil saturation.

Intake vacuum is applied to crankcase via PCV valve, drawing fresh air into crankcase via air breather. This air flow in the crankcase sweeps away sweeps away Combustion by product gases including a large amount of water vapour which includes dissolved chemical combustion by products. This mixture of air and crankcase gases exits often in older engines a simple baffle / screen / or mesh to exclude oil droplets through the PCV and into the intake manifold.

( read that last line again ) A catch can reverses the above trading the droplets after the PCV.

The 2nd function of a PCV which catch can makers do not talk about is to PROTECT the engine in case of a backfire which causes a sudden high pressure pulse in the intake that forces the PCV to close so that the backfire FLAME can't reach the crankcase and ignite flammable fumes and cause damage to engine and possibly YOU

The catch can being installed after the PCV actually creates the hazard and acts like the crankcase , should a backfire flame happen the CATCH CAN will explode
Part 2
whether or not you have a catch can your throttle plate will be exactly the same cleanliness.

Octane rating of the engine is determined during development based on corporate requirements to meet EPA regulations nothing more. Obviously lower octane produces lower power higher octane more power.
The mixture of Unburned gases with fresh gas charge from injectors will actually increase Octane charge not lower it. just as it would if you put octane boost in your gas tank which gets diluted with 25 gallons of fuel.
Part 3
Ram Forum flooded engine owner was lucky, potential damage Fouled plugs, blown plug, blow off valve seat in head, Blow hole in piston top. The longer he cranks the more fuel he is dumping into intake. read back about Backfire ...........
Part 4
Your catch can coming loose dumped into atmosphere probably increased idle speed.
Part 5
Not only robbing lubrication / cooling / and fuel charge. but wasting the fluids the PCV was meant to enhance.

 

[JohnnyDollar]

and this is why you are probably not getting much response.

The pro people like having it, the con people do not.
The lines are drawn.

I have never seen anything published saying they are harmful to the engine,
nor have I read anything from an engineering standpoint really pro or con.

At worst,
I have read that automotive engineers think they are unnecessary, but these seem to be third hand accounts.

ETA:
OTOH,
I have read articles in Car & Driver, MotorWeek and others that seem to think they are useful.

 

[3 G Bee]

I understand but you are missing the engineering effect established many years ago and continues to this day is the fact that the prevention of possible oil droplets entering the air stream is to prevent them from entering the PCV . What the catch can does is collect those same gases after the PCV which is defeating the original engineered solution.

The whole Idea behind the PCV was to contain the oil mist inside the engine not outside of it.

You could have 12 catch cans in series all lined up after the PCV and eventually every one of them will get some deposits it them.

I know of 2 cases where Chrysler has denied warranty due to catch cans and I am sure there are more. just like they deny claims for altered PCM's

All I can say for sure is owners have a choice make it a wise one.

 

[JohnnyDollar]

Seems from what I have read is the "engineered solution" was simply a response to emission requirements.

 

[3 G Bee]

Seems from what I have read is the "engineered solution" was simply a response to emission requirements.

A solution to EPA regulations

 

[3 G Bee]

Seems from what I have read is the "engineered solution" was simply a response to emission requirements.

There is one thing I fail to mention earlier and that is the so called blow by.

Blow by is the burnt gasoline fumes after the spark plug fires forcing the piston down that seeps back through the oil rings to the crank case, most people assume it is in the opposite direction that oil vapours are allowed to come to the top,

The fumes then mix with the crankcase fumes and are returned to the intake VIA the PCV