Catch Can

Hate to be the naysayer of the group but I am of the camp that believes it is not a necessity. Does it catch oil mist blow by yes, but what it also catches is unburnt fuel from the combustion chamber, specifically Cylinders 6 & 8 as well as possibly 1 & 3 .

By design Dodge Hemi Heads are the same part number regardless of whether it is mounted on the left bank or right bank of the engine. The air inlet and oil fill spout on the drivers side of block are the same air outlet on the passenger side of block. Both heads are open to the intake manifold runners of those cylinders only and not cylinders 5/6/2/4. They also open to the valve train at the top of the push rods.

When The injectors open fuel is sent into intake runner at the same time the intake valve opens and gas is sent to the combustion chamber The spark plug ignites the fuel and sends the piston down the cylinder bottom, the cylinder opposite then ignites its own fuel charge but also ignites the 2nd spark plug in the previous cylinder, however the first cylinder has begun to rise allowing unspent gas to exit through intake runner back into the intake.

Having 2 spark plugs for each cylinder 1 plug fires the initial charge the 2nd plug is fired by the 2nd cylinder charge but cannot contain all gas in cylinder before intake valve closes and exhaust valve opens. some goes back into intake and some exits exhaust. Cat 02 sensors

All our intake manifolds are divided into 2 separate compartments, not sure about the Hellcats though. 1 compartment is for the engine air exhaust to PCV valve but this is also the same open intake runner . the 2nd larger compartment is for fresh air intake.

Believe it or not The oil by pass and unspent gases are invisible when heated in the combustion chamber and become solid again when cooled. So even though you have a catch can the gases that have not cooled enough into droplets still travel into throttle body vacuum. Think of Humidity on a hot sunny day in a non air conditioned shop you cannot see it in the air but the cement floor is soaking wet looks like in rained indoors.

The purpose of the PCV is to direct those gases back to intake to be reburnt a second time rather than into atmosphere.

For those lucky Hellcat owners that have the PCV mounted on the valve covers a simple fix if not already done by FCA would be to place a thin metal shield below the PCV valve to redirect oil splash away from being sucked in or up. This was old school tech tips.

The best mod you could do to these cars is relocate your PCV to valve cover provided you have clearance from Valve train. which 5.7 & 6.1 do not and block off the Holes in the head and intake and current PCV locations. or install an electric air pump to vent the engine air like race engines do.
Pricey but are available for our engines. Look at any on line pictures of the 6.1 intake manifold underside with the belly pan removed and the heads intake openings the oblong slots cut into the parts between the above mentioned cylinders and runners and you will see the reason why you think you have a problem. A 2 Sport I think is the name makes a cast aluminum Valve cover with relocated PCV that fits the 5.7 because it is at the rear of the covers where the 6.1 is at the front of intake.
one other point I want to make is if you have a catch can on your car get a lighter and unscrew the can and ignite it before the gases all escape and see if it burns. Oil should not burn at ambient air temps. Oil wells only catch fire because of the gasses not the oil itself.

So in my opinion the catch can is a gimic because it prolongs the exchange of the gases there by allowing them to cool and turn back into liquid state. Move your catch can further away from throttle body and you will increase volume of liquid.

 

Thank You quietpeen I always try to explain my reasoning with factual info and data. I do not want to rain on anyones parade or upset them. But their is no proof provided suporting Catch Cans other than see here is what they prevent. The truth is they create the condition they claim to solve.
Engines with catch cans will still get varnish coated throttle plates. and residual oil deposits in their intake manifolds. The varnish is from Gasoline not oil. The faster an engine can recycle and burn those vapours the cleaner your engine internals ( piston tops ) will be.
Sears sells a very nice water / Air separator for Paint air supply lines, small red and black for about $ 18.00 even has mounting bracket. will do same function as catch can. actually better Micro filter.

If you think logically about a Paint shop air supply system, how does the air get condensate in the air line ? The Motor Pump Heats the incoming air being forced through the air line to the paint gun The longer the air line the more condensate builds inside the lines, so you need to separate it so it does not mix with the paint and ruin the paint job. Same principle for catch cans. Except now Paint shops are installing dryer systems at the beginning of and after the pump to the air supply system to remove the Condensate. and refiltering the air charge.
Your cars AC system has a dryer bottle for the same reason to protect the pump from condensing air inside of it mixing with the fluid and seizing up. Dryer bottles get very hot during summer months witnessed by the condensate on the outside of the bottles that drip under the car.

Incidentally another OLD SCHOOL tip - if you are concerned about carbon build up in the intake or on piston tops Take you car for a ten minute drive to bring it up to operating temp. Park it in your driveway place a board or heavy Cardboard behind your exhaust tips so it does not fall over, get a mist bottle of tap water remove the intake tube giving you access to throttle body Have a helper press the gas pedal while you spray water into the intake. The cool water will break up the carbon on the pistons and it will shoot out the exhaust but do not allow the engine to die out. when the engine bogs down stop spraying and allow it to rev up again. About 10 ounces of water should be enough to clean them. With Carburetors back in the day we even used rice the starch would pick up a lot of carbon. When done check to see how dirty the cardboard is . and beware you will blow a lot of white smoke out the tails harmless vapor.
Cheap and easy I do not recommend using the Brake booster Vacuum hose as some have done because you will get water inside booster another sealed vacuum pump.
If anyone can prove to me there are benefits of catch cans believe me I would have one. But all you hear is look and see what they catch.

Sounds like the Government create a fictitious problem they claim to solve to take more tax dollars from us. OH NO did I say that !!!!!!

 

Yes I have read some post's and articles about that.
The problem using the Booster Vacuum hose is just that It is a vacuum so any chemical, water, air borne dirt particles Humidity, that may get drawn into the booster will eventually contaminate the diaphragms in the booster and rust will destroy the seal. BAD IDEA. I have seen 50 year old Boosters opened and their is ZERO rust inside them in perfect condition. And I have seen 5 year old boosters totally rusted and diaphragms all full of holes because the vacuum hose was left open.
I have not read up on Sea foam and I know a lot of owners use it as well as other products.
All I can say is take what ever you are using and poor a little into a small aluminum foil pie or tart pan. set it in the sun and when it has dried if it leaves a film it will harm your engine.
Whether it has a petroleum base, soap, detergent, alkaline usually not good.

The Brake boosters in our cars are actually dual diaphragms - remove the vacuum hose from the Booster valve and you have no brakes or very hard pedal, hard to stop. Yet the vacuum continues to function, drawing in whatever it can, re connect the hose and you have a very soft pedal pressure that pushes the vacuum air against the diaphragms which expand when braking. Foreign material inside the booster will be floating around bouncing off the diaphragms continually until they eventually puncture making the booster inop. Think inner tube with a pebble inside and when you sit on that pebble you puncture the inner tube. make sense !!

The Boosters come into the plant with a cap over the booster Valve to prevent anything getting inside them during shipping. That cap is not removed until the vacuum hose is connected to it from the engine.

I personally have used nothing but H2O in all my vehicles to clean out any carbon by spraying it through throttle bodies or slowly pouring it into carbs. and have torn apart a few of these engines and quite frankly have not seen the carbon build up that I have seen on some of the engines posted on some sites, It make me wonder what they are doing.

 

Your quite welcome, I post giving my view point and experience hoping to stir some minds and make them think about what they are actually doing to their cars because I always question what is the purpose of this and research it.
Every vehicle system ( function ) has an intended purpose. If you alter it you have to understand what other damage could it possibly cause and work out the entire system before you start so you know what to expect, No Surprises.
Another issue that comes up all the time is stereo systems and guys hack into wires that cause a whole array of issues.
Our vehicles have 5 open terminal blocks throughout the car to tap into to run new circuits for what ever they want to add, but they still cut into other circuit wiring.
The Police Units have the same wiring we do and with the host or lights, sirens, laptops, Mic, etc etc etc they do not splice into any other circuit wiring. HHH MMMMMMMMM.........
anyway I gotta run. Have a great day !!!

 

Wow, I was expecting some feedback on Catch cans surely someone must have some thoughts or opinions pro / con