Catch can test, plastic or aluminium?

Submitted: Tuesday, Dec 25, 2018 at 09:50
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Reply By: Rangiephil - Tuesday, Dec 25, 2018 at 10:28

Tuesday, Dec 25, 2018 at 10:28
Seeing the smaller Provent 100 and clones are only designed for throughputs of 100Litres per minute, it seems crass to test them up to 200litres per minute. See the Mann filter site for confirmation.
I have a cheap clone with stainless filter which trades off efficiency for low impedence. To say that it "failed " at 180Litres per minute is actually success as it is obviously designed for 100 litres per minute.

I maybe will change my filter to get better efficiency to a cotton one for a Flashlube style one. Wesfil do one for a reasonable price and it looks like it fits.

Regards Philip A

AnswerID: 622812

Follow Up By: IvanTheTerrible - Tuesday, Dec 25, 2018 at 10:43

Tuesday, Dec 25, 2018 at 10:43
How bad would your engine have to be if you expect 200 LPM of blow by? I dont run a filter or EGR plate and after 150,000 I stuck a camera in the inlet and it's relatively clear.
FollowupID: 895840

Follow Up By: RMD - Tuesday, Dec 25, 2018 at 11:33

Tuesday, Dec 25, 2018 at 11:33
If towing the EGR is likely to be mostly closed or fully closed, depending on load. Therefore there will be far less heat or no heat or EGR gas to convert any oil mist to sticky goo in the inlet. Distance isn’t necessarily a big factor.
FollowupID: 895841

Follow Up By: Les - PK Ranger - Tuesday, Dec 25, 2018 at 11:52

Tuesday, Dec 25, 2018 at 11:52
True RMD, my electronic device to eliminate EGR ops has an led indicator.
It shines green when powering on, eg uphill, under load, etc, and glows amber when cruising, downhill, etc, to indictate when the EGR would normally be open.

Even up slight hills under very low load it still glows amber, and my estimate is the amber is lit probably 90% of the time hwy driving, slightly less city driving.
Having this indicator light function does open your eyes to how often the EGR is working in various driving modes.
FollowupID: 895843

Follow Up By: 9900Eagle - Tuesday, Dec 25, 2018 at 12:01

Tuesday, Dec 25, 2018 at 12:01

a small BT6 cummins will have 85 L/m new at 2800 rpm and a worn one will be 170 L/h at the same revs.
FollowupID: 895844

Follow Up By: RMD - Tuesday, Dec 25, 2018 at 12:15

Tuesday, Dec 25, 2018 at 12:15
The amount of blowby will vary markedly with oils of different ring sealing ability. Usually oil which seals better doesn’t mist as much and doesn’t turn to goo as easily under EGR gas heat, all equaling cleaner intake and engine internals.
A catch can located at the front of bay will run much cooler than one back in the engine bay where it is heated. Cool condenses airborne anything much better.
FollowupID: 895845

Follow Up By: Ron N - Wednesday, Dec 26, 2018 at 15:39

Wednesday, Dec 26, 2018 at 15:39
One of the important things to remember, as regards the newer and tighter emission-control engines, produced in the years from around the early 2000's onwards, is that all these newer engines are designed to reduce exhaust emissions, by pumping the more undesirable by-products of combustion, down past the rings, and into the oil.

For this reason, the newer engine oils produced since around 2000, have a much higher detergent content, to handle the higher levels of contaminants pushed down into the oil.

In addition, many of the newer engine designs utilise "low-friction" rings, which have both a reduced "inherent" and "applied" pressure on cylinder walls.
Finally, newer engines are utilising high-tech coatings on ring faces and cylinder bores to again reduce friction.

All of these newer engine designs assist in increasing blowby, which is dealt with by the PCV systems designed into these newer engines.
In the same design vein, oil consumption is quite often higher with the newer engines.

There seems to be a certain amount of misunderstanding in many vehicle owners minds, between the PCV system of an engine, and the EGR system. Both of these are separate systems.

The PCV system is designed simply to recirculate crankcase blowby back into the intake manifold, and thereby burn the noxious fumes from the blowby - rather than letting it go straight into the atmosphere as the older engines did, with their Open Crankcase Ventilation system.

The EGR system is designed to recirculate a portion of the burnt exhaust gases back into the intake to lower combustion temperatures and thereby reduce Nitrous Oxide emissions.

The EGR valve bleeds a small amount of burnt exhaust gas into the intake as directed by the ECU.
EGR valves do get clogged with carbon deposits - but these EGR carbon and oily deposits do not all come from crankcase blowby containing oil droplets - these deposits come from residual combustion by-products ejected from the combustion chamber.

These combustion by-products normally come from the increased amount of oil coming up past the low-friction rings, and from the conditions under which the fuel is being burnt.
I personally don't believe crankcase blowby injected into the intake manifold by the PCV system, contributes greatly to the level of combustion by-products.

If you're a lead-foot and tow a lot, or travel constantly at high speeds, your level of undesirable combustion by-products is going to be higher than someone regularly tootling around the city at 60 or 70kmh.

Additionally, if your engine is well-worn, the amount of combustion by-products (and crankcase blowby) is substantially increased, as compared to a new engine.

The PCV systems on todays engines normally contain a built-in oil separator that ensures excess amounts of blowby oil don't enter the intake manifold.

There probably is some minor benefit to be gained from installing a good brand of catch can - but that benefit is primarily catching the more undesirable engine-damaging and polluting by-products in the blowby stream - which are generally produced by excessive amounts of cold running, short trips, and poor maintenance.

Crankcase oil dilution by unburnt fuel, still remains as a far bigger potential engine destroyer, than a few mils of crankcase oil going into the intake manifold monthly.

The bottom line is - I have yet to see, verifiable, independent and thorough testing, done on catch can benefits, utilising two identical vehicles operating in similar conditions, over an extended period.

Cheers, Ron.
FollowupID: 895858

Follow Up By: RMD - Wednesday, Dec 26, 2018 at 17:07

Wednesday, Dec 26, 2018 at 17:07
I am not sold on some of what you mentioned because:
I do not believe for a minute than modern engines are designed to, as you claim, " by pumping the more undesirable by-products of combustion, down past the rings, and into the oil".
There is nothing different to make it "pump" any more than any other engine, escape past rings under pressure. It doesn't pump anyway, it is a gas loss stream of burnt gasses and particulates.
Back in the 70"s Mobil Delvac had a, high as ever, concentration of detergent additive, Far higher than any other brand. Where I worked always used Mobil Delvac in everything, worn engines were clean inside, unlike with some other oils. Nothing new since 2000.

It isn't just the ring pressure on the walls which determines sealing, it is the the performance of the dynamic sliding seal which performs or doesn't perform the sealing, combined with a well performing oil. Some popular oils are rubbish.

Only a very small degree of combustion by product results from engine oil moving up past ring and trapped above the piston, burnt fuel, YES definitely. Many oils are LOW ASH content for a few reasons. Once instance you say there is significant amounts of stuff coming down and then significant amount of oil going up to produce combustion by products. Hang on, you can't have it both ways to both extremes. Has that engine got any rings? If significant amounts of oil were being used the oil would require checking daily, not every 5000 or so. Even significant amount of PCV flow gets burnt and only a small percentage of that and fuel burn gets to the inlet.
My Isuzu oil is far cleaner at 10,000km pre CRD and Turbo engines possibly can be, so there is far cleaner blowby from better burn for the oil to be relatively clean at 10,000km.
Using a full synthetic, the oil is far cleaner at 16,000km than normal oil is at 10,000km. So oil sealing of rings definitely does have some bearing on the whole issue.
Apart from cold running where water can build up, most of what goes out the pcv line is gas with some oil mist. Much of ANY blowby particulates are trapped into the oil, drained out at service change. It is constantly reconstituted into the oil.
Modern Diesels burn and run far far cleaner than pre turbo, pre CRDengines and so the perceived problem is far less anyway. If they didn't have hot EGR flow no one would be worrying at all. Cool the EGR more would make a BIG difference.

Unless there is an engine, ie, seal/inj pump fault, crankcase dilution from diesel is almost unheard of with a CRD engine. They are made to clean burn. 10,000 times less than pre CRD.

Why do you want to see, verified, independent, thorough testing? Most vehicles will perform well and run to well over 100,000km, many far more distance before any consideration of intake is needed. With some devices fitted, far longer, proven fact.
FollowupID: 895862

Follow Up By: axle - Tuesday, Jan 01, 2019 at 09:50

Tuesday, Jan 01, 2019 at 09:50
Well explained RMD, it does open up a area of which is the best oil to use in a modern crd engine though!...….

HNY Axle.
FollowupID: 896002

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