Gen 3 Motor Issues - Piston Soak - Blowby Pressure

Update: Ran the oil for around 300 miles and drained it out. I noticed a bit of e85 froth from the beginning which is expected as you really can't get it all out. But did my best to do some good highway and solid load driving to get it out. No italian tune up bs. Just good hot oil. I also drove around town a bit. The car gets much better gas mileage now. So I've always aimed to get like 51mpg average in the cold winter below 55F ambient temps and struggled to do that (above 55F i can usually get 53-55 average on my tanks as I don't do a ton of interstate). The car now gets much better than that around town from what I see so far. To not get ahead of myself I won't say a number until i run a full tank but its looking good! I'm almost dumbfounded at what i think i see. But soon enough you guys will see what the actual numbers are.
Here is the oil drain of 300 mile oil.
You can see the amount of dislodged carbon that the oil filter caught. So it sounds like i may just keep doing filter swaps and feel it out. The particles are large enough you can almost just clean out the filter lol
I will be going to my parents house next week for Thanksgiving and taking the prius. The interstate there and back is pretty torturous for a Prius so it will be a good test.

Some interesting facts on alcohol fuels:

Under The Influence: Alcohol's Effect On Your Engine Oil

*try and ignore that its engine labs so they are trying to sell you some random racing oil brand btw

 

Looks like it has improved pretty well. The can has been catching a lot of water vapor around town and no oil at all so that has been interesting to see. Here and there you can see the smoke come out of the can when you open the hood to check on it so you know thats where a minute amount of oil consumption goes around town, but around town the can catches no oil and the dipstick has such a small loss its not possible to say if theres a loss or not. Typically I take a photo of my dipstick and then blow it up and measure it with a caliper on a computer screen when i do lol. The trip home since it was raining and the speed limits have been raised now it got put to a good test. Around 520 miles, 75-80mph the whole trip the car consumed what looks to be around 1/5 (22% of dot to dot 1.5L) of a dipstick (i think max grades are around 20% or something). I've heard the dipstick isn't linear in its measurements so i would like to say thats around 0.35quarts of the 1.6qt dot to dot but it may not be. I don't want to add oil to the oil change so i will just do it this way until i drain it around 3000 miles.
It was interesting to note that the can before the trip only contained water, and after the trip there it had some golden oil in it coating the bottom. The two liquids weren't frothed up. So it definitely has some good blowby under loads and higher RPM.
Not gonna lie though it was kinda strange letting the car hold 75-80 on these grades with cruise control as I really felt like i was abusing the car lol. This is the hardest ive really pushed it for sure as I used to let speeds drop down to 60-65 on grades while the truckers are doing 45mph in the slow lanes. So we are going hard on the car to see if this would do it for the average joe who has no idea what abusing a prius means just hammer down.
Total mileage on this oil change is 1100 miles so far.
So if we do use the 0.35qt number thats a consumption of 1qt/3100 miles overall.
If we use just the highway miles as it looks like it didn't consume a measurable amount of oil before the trip thats about 1qt/1500 miles for worst cast scenario with an inaccuracy of some sort.

My previous way of calculation was doing 60-70 on interstate trips measuring the dip stick the same on the same level surface and then adding oil until hit the full dot again got me around half a quart every 400 miles. So
400/.5 = 800mi/qt was my max oil consumption.

Not super sciencey but its still pretty fun to note. Car has more power now just all around as well. Not sure on the amount but it really can maintain good normal speeds no problem now. Even around town when i do pulse and glide at around 2100 rpm i notice my car pulls on traffic better from stop lights at this rpm. Around town in 40-50F it looks like the car is getting a safe 55mpg again like long ago when i first bought the car used. lol

TL/DR:
Around town just catching water vapor and the dip stick isn't moving. Interstate is the big killer. Previous worst: 1qt/800 miles while trying not to blow up my only car at the time. Now the worst: 1qt/1500 miles driving like normal traffic.

*I also ended up not drilling out the upper port. Its still just its tiny little port inside of its massive nipple. Maybe i will do it soon.

*Also, from what I see so far I agree with Chapman. So the car gets sludgy carbon'y ports, valves, fuel injectors from the blowby vapor coating them. But I think since for most of us the oil is the only thing left behind in the intake manifold, and the large amount of water vapor i see in my can, I would almost bet a large sum of money that the cold start knock people experience is largely from the water not the oil as its a lot easier to dry water with a vacuum im not sure its even possible with oil. Besides the fact that the cars are usually so clogged with carbon and sludge that the pinging conditions are already so low it probably doesn't take much. I bet i probably need to clean the fuel injector tips off the car when i do eventually take it back apart as well.

 

Update: I am a bit over 3000 miles now. After the initial level drop, which after smelling my open air catch can was pretty much just e85, it looks like the oil consumption has stabilized. I was going to change it at 3000 miles but it has consumed so little between all of my holiday and work trips on the interstate and normal driving it looks like it makes more sense to change it at 5k.
I will do my oil change and take the intake manifold off at 5k miles.

 

Update: Oil change
6,265 miles on the oil change
18oz of oil consumed
So this brings the car to a quart of oil consumed every 11,137 miles.
So 1qt/11,000 miles
Car runs great and has done a lot of interstate trips at high rpms through the mountains. I get about 2/3 of a quart of liquid in the catch can over the course of the oil change. Liquid is more or less just yellow water and no oil really.
I haven't got a chance to take off the manifold and inspect it yet, but the car is probably consuming less oil now than it did when i bought it almost 7 years ago!
Also, engine bay is clean, no oil anywhere. You do get a bit of smells from the catch can when the car is warmed up and you pull up to stop signs and recirculation is turned off.

 

Yup I am unsealed no vacuum assist on my modification. Wanted to see if it would reduce oil consumption and gunk any further.
Hey mendel, how many oz of oil does your prius use on an oil change with it being so low? At 90ish thousand miles mine was at almost 2 quarts every 10k miles.

 

Record the oil in and oil out to the oz. All engines burn oil. Some just a lot less.

 

Impressive. I typically just use a single quart bottle with the oz divisions on them to go more in depth over a quart or a liter, but it does look like you are pretty close to zero!
Yeah i capped off my intake and intake manifold. Intake is completely sealed off from the pcv system. The PCV system is just two hoses to the catch can without vacuum assist from the intake manifold. The can can be seen in post #36. I just swapped the pcv valve out with a pretty close to 5/8" straight barb connector and routed both 5/8" hoses to the catch can with a filter on top. The car doesn't really suck in through the pcv system without the manifold providing the suction, its just positive pressure or neutral now.

 

Yup I was thinking about that as I typed it. Bill I have about 5 vehicles without catalytic converters as well. You get used to it bud.

 

Bro you are from Kansas. Don't come at me with that dumb redneck crap. You guys pretty much have the same stereotypes as the south. lol
Four came without catalytic converters since they were pre emissions, some are also motorcycles and offroad vehicles. One I did remove the catalytic converters and installed longtube headers with no cats and a tune for e85 and hopefully a supercharger soon enough! Its a ton of fun!
Most of the polution stuff is just fine actually. The ls400 and sequoia's pcv system in the og layout and their catalytic converters work perfectly! Just a cleaning here and there on some things and some replacement hoses and they are good to go! They really aren't known to burn oil really at all and they don't have egr systems outside of whatever they do with the valves.
I find the low tension piston ring cars with long oil intervals to be the ones that have all of the issues and need all the help they can get now.
Even Toyota agrees EGR is a more unreliable solution than they would like to have on their cars and they are going to not using it on the newer powerplants they are producing, instead opting for larger catalytic converters.
On a mustang with longtubes without cats, tuned before and after (so no gains from leaning it out on the tune up top considered), the cat delete only is about 16whp and the longtubes with no cats is worth about 22whp. With a good tune with a wideband o2 sensor they don't smell any different either which is kinda wild. I've heard some folks in areas with sniffer non visual inspections, e85 tuned cars without cats will pass emissions.
If i was cutting the cats off an old carbureted car that couldn't adjust like the new fuel injected obd2 cars i could see the sniff complaint or buying a god awful insanely rich conservative tune from a "tuner" off facebook (some 20 year old with a laptop and a couple tuning credits from hptuners lol) i could see the sniff complaint as well.

Anyways folks, moisture is still being removed from the engine. The main benefit of the pcv system outside of emissions is the vacuum pulled on the crankcase at low throttle input is used to provide a mpg boost. I will take the small mpg hit. I still get low 50s in the winter and 55-60mpg in the summer without vacuum pcv and without EGR.
Sniffer wise the engine bay is wide open and draft tubes are pretty ineffective and messy. The sides of the engine bay are vented as well as all of the air that goes around the engine in all directions, so we are fine on fumes! I've had my non car folk friends ride in the car its not noticeable to anybody outside of me and honestly we have recirc-auto climate pressed 99% of the time.













Synopsis of the thread for all who are reading in the future:

Oil consumption kills these cars slowly over time! Reduce it as much as possible!

Try the piston soak! Stick to overnight intervals though, e85 is really bad on silicone and rubber if you left it in for say a week. It really seems to melt the large majority of the carbon and sludge away in the first couple moments of cleaning anyways and leaving it in overnight got me great results!

When cleaning pay attention to trying to get the e85 in contact with:
intake ports
exhaust ports
pistons and rings
upper compression chamber ceiling
valve seats
and clean those INJECTOR TIPS!

Like the folks who say a 2 stroke can eat a fiber read when it breaks no problem, stick to soft bristle brushes, no metal bristles!