Hello,

So i've read quite a lot about those oil catch can tricks that some(if not most) of the guys with IS250 are using, in order to at least partially solve the carbon buildup caused.

Let's talk about it for a minute...
First we need to know what is causing the carbon buildup, and here's what I know.
1. As a result of direct injection system on most modern engines nowadays, the fuel is sprayed directly into the cylinder, instead from the intake valve ports(port. injected engines)
2. As a result of the positive crankcase ventilation system(PCV) which is returning some of the blown by gasses like, oil, burned fumes, and fuel which happened to get past the piston rings and into crankcase, therefore building pressure which needs to be released somewhere, and in this case, into the intake manifold, so that those left overs can be burned again. -for reduced emissions and increased fuel efficiency.

Now after we know all this, what can we do?
Well, there are several things we have to take into a count, but the most important one, is to simply make a regular oil changes, so that we avoid as much contamination in the returned oil from the PCV to the intake, therefore reduce buildup.
One thing I've heard quite a lot on all kind of different forums, blogs, and even youtube videos, is that some people claim revving the engine to about a red line every now and then will help with the carbon buildup, which is NOT true at all, and I'll tell you why.
-The temperature needed for the carbon buildup to dissolve/burn is roughly between 300 and 400 degree celsius, or about 500 to 700 by F.
-Normally, the intake valves are operating at about 200-C or slightly below this point, while the exhaust valves are much hotter, roughly around 800-C which is why we have way less issues with the exhaust valves, and more with the intake ones.
-I order to get the intakes within the temperatures that the carbon buildup will start to dissolve, we will need much more then just 1 or 2 red lines a day, in fact we will have to redline it for so long, we will cause more bad, then good to the engine.
-Installing an "oil catch can" which idea is to capture if not all, then most of the returned burnt fumes, oil, and fuel from the PCV valve so that they will not end up into the intake, therefore contaminating the intake valves with sludge.

Now, this one with the oil catch can has caught my attention and I want to talk about it(as well as the other topics above of course)
Correct me if I'm wrong somewhere, I may be, but that's just me sharing my knowledge from the research that I've done.

Has anyone tried, or already installed an oil catch can and what are the results? Does it really help? -I mean, ot theory it would, but I want to see some real results.
What are your suggestion on the topics mentioned above?
What is your solution?

 

Hi,

Search 'oil catch can' and 'occ' on the 2IS forum, you will see what the members here have done.

 

Short trips and never reaching full operating temp creates far more deposits than the blowby itself...

If a vehicle is making 6 10 minute trips per day, it's rate of accumulation will be exponential compared to a highway car driven 18 miles or more making 2 trips.

Why so different? Each time that cold engine is turned off, open valves allow combustion gasses back into the intake tract along with everything mentioned above to settle in the plenum walls and valves whereby the build-up begins. This includes both sides of the TB due to the PCV system.

FWIW I'll argue otherwise and say that long runs at RPM can and do pull oil film from ports and valves do to higher port velocity. This alone won't prevent buildup of those short trips.

That said, most don't understand that multiple short trips is severe duty and requires shorter oil change intervals but neither Jiffy Lube or the dealer ask these questions so it never happens as no one reads the manual.

 

You don't want to tie both PCVs together into the same catch can going to the LHS valve cover...makes eerie noises and froths the oil real bad. I was running a generic OCC on the LHS valve cover and a PVC union stuffed with a stainless scrubbing pad to increase the surface area for oil/combustion vapors from the RHS cover, but now--because the engine's days as an appliance are just about over--I'm running the factory hoses and routing, with a high concentration of SeaFoam in the oil, as well as sucking a can into the brake booster line every now and then. I'll put the oil catch devices back on when I'm done tinkering and am ready to forget about the car for a few months.

Most folks don't realize that our carbon is a combination of oil vapor and combustion gasses that get past the rings. If I re-ring a short block, I'll be playing with the idea of a gapless 2nd ring and keeping track of the carbon. Mixing a decarbonizing agent like SeaFoam into the oil at the end of a change interval and running the engine very hard before the oil change itself will help break up some of the stuff that sucking it into the intake while idling won't reach...just be conscious of everytime you decarb, you're loading the oil up with gunk. And it should look like you're laying smoke for a major invasion, as the carbon and decarb agent will typically billow white smoke when burned

 

Last oil change I ran seafoam in the crankcase. It was about 300 miles before change. It definitely made a difference. Engine sounded way smoother on idle afterwards. I also shined flash light into the oil cap opening. While definitely lifted some varnish that was on that spot beforehand. I wouldn't recommend if you have severally neglected oil changes.

 

Alright, so does anybody have a back to back to comparison of the valves from the same car, same engine, same mileage, etc. with, and without occ installed after the pcv?
I'm just wondering, because many people talk many different things, but I'm yet to find any solid proof of anything or a proof of concept at all.
On theory it should, and it would help, but that's just theory...

 

I installed it on my 2011 awd is250. Fills up about 1/3 after 3000km...the generic ones off amazon. After a long road trip drive ive noticed its mostly gas or gas vapor..super thin and reeks of it. In mostly city it does collect more oil vapors, less gas content. Idle has smoothed out used to get lumpy cold start idle. that has gone away 90%.

 

Repeating myself but, you need to compare how they are used. Miles is fare less critical than those who drive 3 miles and turn it off.

Those catch cans that fill full of water are from vehicles doing short trips and never reaching operating temperature.

A thanks to those who provide information is never a bad thing either...

 

I do think a catch can does help cutting down carbon build up, at least to a management level. But don't expect wonders. Here are some pictures I took before the catch can and after on my 2006 is250. I also use CRC GDI Intake Valve Cleaner before I change my oil at 8-10k mark. Hope this give you some idea what to expect with a catch can. For me knowing how much is collected in 5k, it is totally worth it to install the catch can.

The before photo was taken around 150K km




This was taking recently around 240K km. Sorry about the crappy photo for the valve shot. I dropped my android photo on the concrete floor just when i was about to take picture with the scope camera. Half of the touch screen stopped working, and I had to use my other iphone to take photo from my cracked android phone.



This is how much the can catches every 5K km.