Why specifically are oil catch can(s) needed

[SVTinAR]

From my own perspective I remember what unfiltered PVC circulation did to the Lightning intercoolers and I started using them for that reason. But, oil can only degrade octane level of the fuel mixture and the oil must be very finely atomized in the PVC return which would affect it the most - otherwise my main question would be why doesn't Ford do a better job of baffling the PVC valve area in the valve covers? But maybe a lack of effective baffling is the issue.

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[64Chevy]

Thanks for posting this. However, this video is a good example of why I am asking the questions. He states that this is a "mandatory modification" for both the 5.0 and 5.2 liter engines. I didn't think there were concerns about low tension oil control piston rings in the 5.0, but I may not be informed. Regardless, he points to the oil in the separator as justification for the mod--not gunked up intake runners, intake valves, etc. So why isn't this an important mod on many other high performance engines (GM V8's come to mind)? If I put one on another car, would it also collect oil?

I do get that the high RPM nature of the Voodoo, especially if you spend a lot of time there, may blow by more oil than other performance motors. I'm not sure that's proven, but is seems logical. But I'd still be interested in seeing evidence that this oil blow by "matters". I'm not shading anyone who installs these--at the worst they are insurance that you might not need--and I'm probably putting in at least a passenger side one. But my life's work has been in science and medicine, and I have seen numerous examples of something the seems logical and good and ends up not being either.

Ford made 'em, so one can also ask did Ford make them because they are needed for everyone, because they do serve a purpose when these cars are tracked hard, or because Ford is ultimately in the business of making money?

 

[Tank]

The purpose, as explained in the FP catalog is to,
“separates oil vapor from the air in the PCV system”.

This helps to maintain a proper air fuel
mixture that isn’t diluted by the vapor.

 

[stanglife]

I'm with you, OP. Hard to prove the benefits other than it makes people feel good..there is a perceived benefit of preventing some of that oil from recirculating through the intake manifold. These engines are not direct-injected, so the intake valves themselves will get washed with fuel, keeping them clean.

I never installed mine, as I was hearing people mention oil consumption issues and I just didn't want to change anything. I've never had a consumption issue, so again, I'm not going to change anything.

One reason that you might use a catch can (or any technology/method that would reduce oil being introduced into the combustion process) is that a significant presence of oil in the combustion chamber will reduce the effective octane level, potentially causing detonation on a high-compression engine, like this. That's actually my #1 reason for considering a catch can, but like I said, my engine isn't ingesting any noticeable amount of oil.

 

[64Chevy]

Thanks to all for weighing in. The decreased octane (especially when there is a lot of blow by at high RPMs and high loads) could be an issue, to be sure. I'm not certain it matters for a once a drive sprint to redline on a freeway on-ramp, but I can see that argument being a good one for the track. Whether that matters on street driven cars isn't clear to me (and likely isn't really known).

 

[galaxy]

I'm with you, OP. Hard to prove the benefits other than it makes people feel good..there is a perceived benefit of preventing some of that oil from recirculating through the intake manifold. These engines are not direct-injected, so the intake valves themselves will get washed with fuel, keeping them clean..

Nailed it (on the DI comment). Except the only thing I'd slightly disagree with is that it's not a perceived benefit. The catch cans actually do accomplish this. Sure there's a debate about the quantifiable benefits of removing that oil mist entering the combustion chamber, but that oil is removed none the less. Benefit? Yes.

I never installed mine, as I was hearing people mention oil consumption issues and I just didn't want to change anything. I've never had a consumption issue, so again, I'm not going to change anything..

There is no way on this planet or any other that an oil catch can causes, adds to, or detracts from an oil consumption issue.

One reason that you might use a catch can (or any technology/method that would reduce oil being introduced into the combustion process) is that a significant presence of oil in the combustion chamber will reduce the effective octane level, potentially causing detonation on a high-compression engine, like this. That's actually my #1 reason for considering a catch can, but like I said, my engine isn't ingesting any noticeable amount of oil.

Nailed it. Funny note Jeff that you made this comment right after your own comment in this same post that a catch can is basically a placebo, LOL ;)

 

[zzrat]

Great read. Many points that get you thinking. Can't help but think while Ford offers FP oil separators as an over the counter add on they must have felt during R&D of the engine that they weren't necessary. We all found out recently that the R's had a little variation internally than the non-R's. Looks as if the odds of the R's being used more so on the track with higher RPM's the oil separators would be another stock item on this version of the 350. The video posted certainly makes you wonder.

 

[galaxy]

Great read. Many points that get you thinking. Can't help but think while Ford offers FP oil separators as an over the counter add on they must have felt during R&D of the engine that they weren't necessary. We all found out recently that the R's had a little variation internally than the non-R's. Looks as if the odds of the R's being used more so on the track with higher RPM's the oil separators would be another stock item on this version of the 350. The video posted certainly makes you wonder.

I'm sure one of the factors that goes into the decision is the service involved. What are the ramifications of never ever emptying that thing? I don't know, just offering up the thought, but I'd bet money it was a factor. Would bet the rest of the money the EPA is another huge factor in the decision.

 

[HoosierDaddy]

Don't forget LSPI. Search will find reputable studies showing oil is a major cause. Oil standards were updated to minimize the impact which is NOT stressed in marketing which tells you it wasn't done to increase sales/market share.

 

[64Chevy]

Don't forget LSPI. Search will find reputable studies showing oil is a major cause. Oil standards were updated to minimize the impact which is NOT stressed in marketing which tells you it wasn't done to increase sales/market share.

That's interesting. This is a completely unsupported thought, but it does make you wonder if LSPI events are one of the things hurting the Voodoo's rings? This, coupled with the octane decrease, could be a thing.

Which then raises another question. Presumably the biggest risk of both of the above is due to finest droplets in the oil mist. From other reading oil catch cans are variably effective, and one of the variables I read about was the can itself being as cool as possible. So this would be both engine bay (or outside the engine bay) location and material of the container itself (so does the plastic of the Ford Performance units cool better than the billet aluminum of other units)?

 

[stanglife]

Nailed it (on the DI comment). Except the only thing I'd slightly disagree with is that it's not a perceived benefit. The catch cans actually do accomplish this. Sure there's a debate about the quantifiable benefits of removing that oil mist entering the combustion chamber, but that oil is removed none the less. Benefit? Yes.



There is no way on this planet or any other that an oil catch can causes, adds to, or detracts from an oil consumption issue.



Nailed it. Funny note Jeff that you made this comment right after your own comment in this same post that a catch can is basically a placebo, LOL ;)

I didn't say that it's a placebo. What I was getting at is there isn't any actual testing available that proves it to be a benefit on this particular car. With the lack of actual facts, it's as likely that it could cause an issue as it is to resolve an issue (that no one knows exists). You can not say with 100% certainty something that you do not have actual testing on - you're just programmed to believe it. My comment about effective octane was dependent on a measurable amount of oil entering the combustion chamber and as I noted (in the same statement) - if that's not happening for me, it's (installing the can) not a consideration. I think you might have read what you wanted to read there ;)

 

[stanglife]

I'm sure one of the factors that goes into the decision is the service involved. What are the ramifications of never ever emptying that thing? I don't know, just offering up the thought, but I'd bet money it was a factor. Would bet the rest of the money the EPA is another huge factor in the decision.

True - just something else for people to ignore and cause issues down the line. Also realize that Ford Performance is in business to turn a profit - you cant ignore the possibility that the suggestion to install one might have come from someone without an engineering degree.

And just to be clear, I'm not saying they are worthless. I'm saying the same thing I say in a lot of debates like this - we do not have the information to prove it one way or another). I haven't heard of any holes on pistons or any reports of detonation from tuners who surely would have seen it on the dyno - but that's just one aspect of this. People really want to put the simplest explanation rule to use but commonly it's the simplest explanation "that they understand" that they are applying to a problem..when the best solution could be to do nothing...we just don't know at this point.

 

[64Chevy]

I think what some folks do is confuse "it works" with "its needed". Clearly the catch cans collect oil, so they work. The problem is empiric evidence that they are needed.

 

[stanglife]

I think what some folks do is confuse "it works" with "its needed". Clearly the catch cans collect oil, so they work. The problem is empiric evidence that they are needed.

Agree. I'll take it a step further. Do we know how much they would catch if they were not there ;) That is, how much oil mist actually flows through that line without the catch can present? Does the existence of the device as a void between points A and B actually increase or decrease the amount of oil vapor flow?

 

[64Chevy]

Agree. I'll take it a step further. Do we know how much they would catch if they were not there ;) That is, how much oil mist actually flows through that line without the catch can present? Does the existence of the device as a void between points A and B actually increase or decrease the amount of oil vapor flow?

And to pile on, what percent of the oil vapor are they "catching". I used to fit respirators for plutonium environments--it is hard as hell to get a good fit. So when you are in the hardware store and see masks/respirators advertising how effective they are, that is a statement about how well the filter works in a lab, not how well it works on your face. And the stuff the masks miss are the smallest particles around the edges/seals, which are the most dangerous. Could be a similar situation with catch cans.

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