OBS Catch Can

[Schurkey]

I've never fully understood the reason behind a catch can. I remember back in the 90's when I had a Mk3 Supra it was a popular "mod". Is it just to collect the oil/vapors without burning it? What is the harm in just burning it?

Folks with excessive blow-by due to worn-out engines, and folks with aftermarket valve covers that don't have oil baffles for the PCV system seem to gravitate to them rather than fixing the REAL problem.

An engine in good condition, with a properly-baffled PCV system in good repair, has NO problem with oil vapors or moisture going through the intake manifold and getting burned in the combustion chambers.

An oil-sucking pig could have problems, but the solution is to fix whatever is causing it to suck oil, rather than filtering/separating the blow-by fumes.

 

[2drXmobb]

Folks with excessive blow-by due to worn-out engines, and folks with aftermarket valve covers that don't have oil baffles for the PCV system seem to gravitate to them rather than fixing the REAL problem.

An engine in good condition, with a properly-baffled PCV system in good repair, has NO problem with oil vapors or moisture going through the intake manifold and getting burned in the combustion chambers.

An oil-sucking pig could have problems, but the solution is to fix whatever is causing it to suck oil, rather than filtering/separating the blow-by fumes.

Your right but I've seen good running engines with soot and carbon build up in the intakes . I know it's from the PVC and the egr. Would it be beneficial for a good running engine to have a catch can? I mean less oil vapors and moisture wouldn't hurt would it?

 

[Vjcamp]

You have 425K miles on a 6.0? I didn't think anything short of a diesel would reach that kind of mileage.

I've never fully understood the reason behind a catch can. I remember back in the 90's when I had a Mk3 Supra it was a popular "mod". Is it just to collect the oil/vapors without burning it? What is the harm in just burning it?

I have 325k on my ‘93 4.3L

 

[GoToGuy]

If you live where there is humidity, the hot cold cycles are going to cause condensation. It's science. If you think that you have excess crankcase moisture, is your PCV system functioning correctly, have you checked it? Installing a catch can, are you then capturing oil vapor that would have stayed and been recovered within the crankcase , PCV system?

 

[Schurkey]

I've seen good running engines with soot and carbon build up in the intakes . I know it's from the PVC and the egr. Would it be beneficial for a good running engine to have a catch can? I mean less oil vapors and moisture wouldn't hurt would it?

There's no point to a catch-can. As you said, engine can have light-to-moderate build-up in the intake and still run good.

The catch-can is simply not needed. And it's not like "typical" drivers would ever remember to empty the thing when it got full. Hell, folks can't check their oil or empty the crumbs out of the toaster on a regular basis.

Let the engine digest (a normal quantity of) those vapors like the engineers intended.

And if there's an abnormal quantity, fix what's wrong instead of putting a band-aid on it.

 

[GoToGuy]

What works for high performance dragster engines or formula one, or dry sump designed by engineers and proof tested, does not necessarily equal your daily street vehicle install.

 

[KansasOBS]

There's no point to a catch-can. As you said, engine can have light-to-moderate build-up in the intake and still run good.

The catch-can is simply not needed. And it's not like "typical" drivers would ever remember to empty the thing when it got full. Hell, folks can't check their oil or empty the crumbs out of the toaster on a regular basis.

Let the engine digest (a normal quantity of) those vapors like the engineers intended.

And if there's an abnormal quantity, fix what's wrong instead of putting a band-aid on it.

I'm not sure intended would be the right word, more like mandated.

Oil through the intake leads to carbon build up, which washes into the oil, and creates added wear, also lowering the miles between oil changes. But sucking it back into the engine appeases the greenies.

Its about like DEF fluid. Saving the environment shipping this stuff all over the country, the production of pallets to ship it on, the production of all the jugs and straws, the production of the cardboard boxes, and the tape and shrink wrap that holds it all together. But hey no black stuff out of the exhaust.

You may be right about people not emptying them, kinda gimmicky to me anyhow. Id just vent to atmosphere with a filter.

BG products used to, and probably still does sell a kit with a nozzle to wash out intake manifolds, they may run fine all nasty, but Ive seen it cause runability issues also.

 

[99xcss4]

pcv is need with out crank case ventilation every gasket and seal will bow I agree with venting the crank case to atmosphere and sending it to the intake but unless you have a road draft tube is there really any other option maybe a vented catch can I do not know it is way above my pay grade

 

[Scooterwrench]

Catch cans are only needed(sometimes mandated)on race engines that run with little manifold vacuum most of the time.
What you need is rings!!!!!

 

[Schurkey]

I'm not sure intended would be the right word, more like mandated.

PCV was invented and used in limited applications before it was mandated in the early-60s.

Oil through the intake leads to carbon build up, which washes into the oil, and creates added wear, also lowering the miles between oil changes.

Yeah, that's why engines today are pretty-much finished by a hundred-thousand miles.

The oil in my Trailblazer gets changed at 26K miles, and still tests good via lab analysis. I do change the filter at 13K, and top-off as needed. But this engine only has 280K miles on it with zero internal repairs beyond spark plugs, so I don't know how it's going to work long-term.

But sucking it back into the engine appeases the greenies...

...Id just vent to atmosphere with a filter.

On a cost/benefit ratio, PCV is the single-most-effective anti-pollution device ever created for automotive engines. Venting a crankcase to atmosphere is not just silly, it's less-effective at removing moisture/acids from the oil.

BG products used to, and probably still does sell a kit with a nozzle to wash out intake manifolds, they may run fine all nasty, but Ive seen it cause runability issues also.

I don't know about BG, but Seafoam has an aerosol product with a huge-long straw and straw-bender to clean intake manifolds. I don't have a great impression of Seafoam products, but I've never seen 'em cause problems and who knows--in some cases they may actually work.

You must be registered for see images attach

www.amazon.com/Sea-Foam-Acting-Engine-Cleaner/dp/B015T5Y8CG/ref=sr_1_5?crid=7BOPT7EBBOUW

xc_hide_links_from_guests_guests_error_hide_media