2017 supplement doesn’t mention catch can

[MHW100]

I notice that Ford didn’t mention in the 2017 owners supplement anything about Track Apps and using a catch can on track days. This section is in the 2019 manual.

Are they saying that you should not be using a catch can pre 2019?

Are they saying that you should not use a catch can on the street at all?

I read somewhere that it could be harmful for seals etc in these high compression NA engines to be running a catch can and only are beneficial in boosted applications. I realize there’s debate about whether they are truly beneficial at all but I don’t want to damage the engine either.

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[galaxy]

No clue where you got any of that info. There’s no debate. Catch can good. Boost has nothing to do with it. No, I do not know why it’s not in the pre ‘19, but that is not the message they are tying to deliver.

 

[MHW100]

Not so sure about that. The few Ford engineers I’ve met a few years said they weren’t necessary and no evidence they possessed through testing convinced them they were beneficial. I believe they were engine guys if I remember correctly.

I note that they are on the 500 and I found that 2019 citation which peaked my curiosity suggesting that there might actually be some evidence specific to 5.2 testing. Unfortunately I lost contact with them or I’d ask them directly.

 

[mavisky]

Catch Cans aren't rally smog friendly in most forms and that's why they aren't on the car from the factory. Ford was able to make it work on the GT500 by having it dump back into the valve cover, but even then they weren't installed on the factory floor and had to be dealer installed.

 

[luc]

I have passenger and driver side ford catch cans on my , track only, 17 pp1
Both collect oil…. Therefore this oil is not regurgitated by the engine through the intake manifod
So obviously they are beneficial

 

[NightmareMoon]

I have passenger and driver side ford catch cans on my , track only, 17 pp1
Both collect oil…. Therefore this oil is not regurgitated by the engine through the intake manifod
So obviously they are beneficial

Well the valve covers on the GT are not the same as the ones on the GT350. The 15-17 valve covers (at least the divers side cover) will definitely accumulate oil and push some through the PCV lines under the right track circumstances, and we know that more common on the passenger side.

The GT350 valve covers don't seem to be as problematic, but since Ford sells them for both sides, that tells you something.

 

[Jaymar]

I kind of' feel like catch cans are the vitamins of the automotive world. There may be a few isolated incidents where somebody needs one to help a particular situation but somebody will always want to sell you one that makes everything magically better than life without it and it's a miracle that we managed to survive all those years without them.

 

[luc]

Well the valve covers on the GT are not the same as the ones on the GT350. The 15-17 valve covers (at least the divers side cover) will definitely accumulate oil and push some through the PCV lines under the right track circumstances, and we know that more common on the passenger side.

The GT350 valve covers don't seem to be as problematic, but since Ford sells them for both sides, that tells you something.

I have gt500 aluminum valve covers on mine
Much better baffling with 1 way silicone drain valves but still get some oil in both cans

 

[Hack]

I notice that Ford didn’t mention in the 2017 owners supplement anything about Track Apps and using a catch can on track days. This section is in the 2019 manual.

Are they saying that you should not be using a catch can pre 2019?

My assumption is that they just hadn't considered adding it to the owner's supplement originally and then they decided to add it. Probably they like having the small additional revenue stream from selling a few catch cans.

Are they saying that you should not use a catch can on the street at all?

I read somewhere that it could be harmful for seals etc in these high compression NA engines to be running a catch can and only are beneficial in boosted applications. I realize there’s debate about whether they are truly beneficial at all but I don’t want to damage the engine either.

So, going back to what a catch can does. It merely condenses some of the oil vapor coming from inside the engine block and prevents that oil vapor from re-entering the engine and going through the intake.

Most people think this is good for the engine because oil vapors can cause detonation. They can also condense on valves and cause carbon build up inside or outside the cylinder. Oil vapors can contaminate and reduce the life of your catalytic converters if they don't burn completely in the cylinder.

The oil vapors generally come from the oil being stirred up by the oil pump, crankshaft and other internal components that fling oil around. Vapors can also come from imperfect piston ring seal (blowby).

The catch can is placed into the PCV system. I suppose if the catch can restricts the flow of the gasses from the block it could cause some materials to push through seals. However, this would happen even more so on a boosted application where there's more of a tendency for combustion by-products to get past the piston rings. And typically there isn't a high flow rate of combustion by products or vapors from a healthy engine, so I doubt that restriction is much of an issue normally.

I guess personally just knowing what a catch can does and from seeing what engines look like when they have miles on them - I would by far prefer to run a catch can versus not having one. Even if it doesn't seem to catch very much I think it's better for any gasoline engine to have fewer contaminants coming through the cylinders. The Voodoo is better than a lot of more modern engines because it has port injection only, which cleans the valves better than a direct injection engine would. But still, I don't want oil in the combustion chambers.

 

[JAJ]

@Hack pretty much nailed it. When it's running, the engine produces a cloud of tiny oil droplets inside the crankcase from all the oil flying around in there. The higher the RPM, the more oil droplets.

A catch can is designed to capture and redirect oil droplets that get into the PCV system. If they get into the intake tract, chemicals in the oil formulation that aren't flammable will form deposits inside the cylinders on the valves and piston tops and they can also poison the cat converter. For a daily driver, it doesn't matter much, but for track use, this isn't a good situation.

As for why Ford doesn't install catch cans from the factory, my opinion is that they realize that most customers won't benefit from them, and they also don't want to put (or more realistically, "hide") instructions in the Owner's Manual about having to drain the catch cans regularly. No upside and lots of downside from Ford's point of view. So, catch cans are an option that attentive owners can buy, install and maintain.

Going back to the OP's question, there's no downside to running a catch can on an NA engine. Heck, Ford works hard with baffling inside the valve covers to keep oil out of the PCV system, and all a catch can does is improve the performance of that oil-blocking system.

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