Gen 3 Motor Issues - Piston Soak - Blowby Pressure

Anways... I will go work on doing the piston soak and pcv modifications for now. More updates to come.

 

Fair enough. I will quit being a dick and just say I don't know enough. lol @ChapmanF

 

@rjparker What are your thoughts on the highlighted quotes?

 

So it depends. You only use a pcv check valve if you have a vacuum operated crankcase ventilation system. So like stock. The stock pcv valve does a couple things:
1. it is a check valve. So it is spring loaded shut by default to avoid intake manifold air reversing and going back into the crankcase.
2. It is a spring loaded valve so it slides back and forth to reduce pressure in the crankcase by using the vacuum of the intake manifold or pressure of the crankcase to open.
3. If the conditions are right the valve can also open too much and then seal off flow to avoid drinking too much oil. So a good example would be if you engine braked a prius at 5500 rpm the valve would have enough blow by from the crankcase and suction from the intake vacuum that it would close off. Then the excess pressure just goes out the top breather port.
So then what I am proposing since it seems like the blow by pressure in my 2010 prius' crankcase overwhelms the stock system is just doing a vent atmosphere catch can. So its not a vacuum leak. What you do is plug the oem pcv ports on the intake, and then route your hoses to the catch can instead. In this format of crankcase ventilation there is no vacuum so you don't use a pcv valve hence the straight connectors and going large.

Actually not kidding on the purpose of the pcv system though besides reducing emissions and cleaning the oil by sucking out the contaminents for them to be burned. The main factor being to reduce pressure so you don't blow every seal in the motor, the secondary benefit of the stock style system with vacuum is if you can get a vacuum on the crankcase or any reduction in pressure the pistion is easier to push down since the crankcase pressure isnt fighting the combustion chamber pressure (blow by from rings not being textbook perfect adds to crankcase pressure). So this is why drag racing guys will use vacuum pumps. The pumps can be tuned to evacuate more as rpms rise as they are typically belt drive. So you can pretty much eliminate crankcase pressure if done correctly and/or go too far negative and suck things past the seals into the system lol.

Mendel if you have a pcv system connected after the maf sensor any entry and exit ports need to return into the system as the air has already been metered for combustion. So thats why it would be considered a vacuum leak. If your pcv system is before the maf or outside of the intake it isn't metered and not a vacuuum leak. *It also will have no vacuum as its not connected to a vacuum source from the intake lol

Toyotas ecus are pretty good at adapting AFR and idle though. I think they will go plus or minus 20% on stock ecu inputs and outputs without a piggy back ecu or hard parts actually altering outputs. So say if you change any of the pcv, or intake tract stuff behind the maf, you just need to do a battery disconnect and let the car relearn idle or you will have a wonky idle. All toyotas are like this by the way. Well I say all but the sequoias, ls400s, prius, corollas, and tacomas that i have encountered in my personal time lol.

*Also #3 up top is why high load high rpms lots of on/off throttle inputs will consume a lot of oil in road course track cars. So sometimes people will undo the vacuum layout and go to a vent to atmosphere setup while on track to avoid chugging oil, and then put the system back to vacuum operated when they leave.

 

I meant to quote post 27 instead*

Honestly at this point i am pretty hesistant to buy a new Toyota. Their 4 cylinders since 1998 have been very hit or miss. Thats almost an understatement, but could also be because I hold Toyota to a high standard and expect more. But I also feel that way about all vehicles now. Better to wait until they get into the high mileage and see what problems show and then go find a good model and buy a low mileage example. lol
This is more or less how I ended up with a 1st gen Toyota Sequoia 4wd pre vvti and a VVTi ls400. Both "million mile capable" vehicles per the fun headlines. Both easy vehicles to own, transmission dip sticks, no oil consumption, no blow by, really just no problems at all. Just standard old vehicle problems replacing rubber here and there and standard maintenance (joints, timing belt, fluids, etc). By the way my current sequoia has 298k and consumes almost no oil. Like all vehicles consume oil. I will measure in and out, tilt the drain pan to get every drop, and I'm usually missing maybe 1/4 quart or less. Thats spectacular. Hopefully its not because their is just gas in the oil instead lmao. I doubt it thought it runs like new.
A friend of mine also has a 03-08 corolla and he has maxed the odometer out on it and its still going not consuming any oil just regular maintenance here and there lol

 

Yup I agree. Yeah Mendel it is a valve for a reason. It needs to be open and closed at different times. If you stuck a large straight connector into the oem style vacuum system instead of the valve the oil consumption would increase. Although I don't really agree with the orifice style that gm does so often it also works to a certain degree as well.

 

Cleaning done overnight and morning and lunch. So not 24 hours. But here are some photos and videos:
*So i drained the oil and removed the oil filter before i started. All of our cleaning fluid will be going into the crankcase and intake and exhaust ports so its easier to remove the oil first.
1. Before Cleaning intake ports:

I actually forgot to snap a photo of this so this is taken from another member but for all intents and purposes it works. The intake ports and valves are basically vanta black.

2. During soak. So I did manually clean these ports with a soft toothbrush and a vacuum. You more or less move the fluid around to get it to soak in better and the carbon more or less just melts off pretty easy. Some is not reachable by toothbrush and is also a bit more baked on as you get closer to the combustion chamber. But it was entertaining to do while waiting for the piston soak.


3. First pour into the cylinders. So I actually was doing them one by one with the compression stroke and then just went ahead and filled them all. So as I'm filling this far cylinder you can see what it looked like on an initial pour.

4. Vacuuming out the ports. Giving it a bit of swirl kinda blast it a bit and helps.

5. Before the overnight soak after the manual cleaning with the vacuum and toothbrush

6. Next day after soak, vacuumed out to check progress. Still a bit wet. In the wet areas you can see the stainless steel a bit better.

7. Next day after i poured some fluid through a couple times this is what i ended up with. Fluid is cleaner and goes through faster.

8. Next day photo


9. catch can hose (upper and lower are both routed to my can as the picture is unclear)


10. Engine bay with can


*before the below I just turned the steering wheel to get the wheel out of the way and got a 19mm socket wrench and used it to hand crank the engine to released the fluid. By hand its still pretty easy and it will hit you in the face so be warned. Cover the cylinders with a rag and use eye protection.

So once i got done with using the liquid i made sure to dry out the what i could, jack the car front back side to side to get it all out the oil drain port. Then i put my new oil in when satisified. With the new oil and filter in I started the car without the spark plugs in and let it "run" for 30 seconds. Even though the car has no spark plugs the car will crank over and think its running if you let it. Pretty impressive. After 30 seconds shut it off and let the car dry out for a couple hours and then came back and put the spark plugs in and fired it up. Car fired up fine and I was afraid of the unknown amount of of fluid in my exhaust so i let it run up to 182F on my inclined driveway. Once that was finished I put my hot air intake back on and went for a drive for an hour. Car seems no different it still just runs well doesn't knock and doesn't have any check engine lights over the p0403. lol
Still has blow by so I'm not good at measuring that one. But I will change the oil soon and then run it for 3000 miles and track oil consumption and see how it does. If it improves I will do our piston soak again for a week straight for maximum effect.
All in though I'm happy for the $5 I spent on the cleaning besides the catch can which was around $60 total.

*I also went ahead and did my intake manifold clean and soak again. Was still pretty good. Didn't document it as everyone knows how to do it.

*I'll have to figure out the quality on my videos. Between google drive, iphone, and prius chat none of the formats love each other.

 

Honestly what i used is pretty hilarious. Its just e85. I bought two gallons and thats what i used. People underestimate how great of a fuel system and carbon cleaner just good ole ethanol is. Nope it is safe on ABS plastic and metal and non caustic. But Mendel you are correct. When we produced plastics we used certain solvents to remove the leftover plastic from those threaded inserts which were from bad batches of parts after we removed them from the parts thermally lol. So if anybody trys a legit top in cleaner careful getting it on things and read its msds for compatibility.
You know thinking about it now it is pretty atrocious how much carbon build up this car had. I bet it had noteable carbon buildup on every inch of the cylinder and rings including the top of the combustion chamber if the intake ports had that much build up. These cars look exactly like Direct Injected Audis when torn apart to clean lol. Which is really a large insult.
I just lubed my caliper guide pins at all 4 corners as well again so again adding another variable to my testing, but I'm in a hurry with lots of things to do.
I will more than likely run the oil for say 60ish miles and then change it and do my monitoring. I'm pretty dang excited to see the results. I bet this car should run great. Or not. Who knows ya know?

 

You would be surprised. I have had motorcycles that had road draft tubes pretty late into last century. Also the pcv vent that goes into the stock airbox on half of them and allows the oil to pool up in the bottom of the airbox and allows the oil to be drained through a drip tube with a cap at the end. lmao. And that setup (not the draft tube) is on my 2000 cb750 that is known to be one of the most reliable motorcycles ever created doing probably 100k+ miles in one of its original forms back when nobody even had odometers with 6 digits lol.

Mostly a fun fact though I'm in agreement with you.