I don't think the tech is correct. A retarded spark may stay retarded for a few tanks for safety. But, your system will not let a car knock for a few tanks before doing something about it. Just my two cents

 

 

This video is very detailed on flaw the RS motors have. There is a flaw in the design with the RS block cracking at the head studs. So I was wondering if we have a good picture of the side profile of the 8AR?

 

Thanks for posting. you should just tell us why the engines were brought in. we're adults and can decide for ourselves whether or not to "panic."

they're just engines.

if anything you'll make people care for their cars better.

did they throw misfire codes possibly related to the caked intake valves?

 

^.....umm you're getting hot... real hot.

 

*panicking intensifies*



jk. So is using seafoam regularly or something to clean the valves something everyone should start doing? Or is it too early to say if there is a different root cause unrelated to fuel?

 

I didn't say anything...

 

I would suggest Seafoam with each oil change, BEFORE THE OIL CHANGE but on the same day or such. This is because of blow by and the fact that the Seafoam is breaking off carbon. The carbon is likely to get into the oil, so why contaminate new oil. This maintenance wouldn't hurt anything, even if you didn't have the carbon build up.

Another (more fun) route would be investing in a water/methanol injection system. Not only have they been proven to clean engine internals very well, they increase power.

 

Thanks for the... ahem.. clarification. lol. I don't know if seafoam will help much in preventing buildup. it might flake some microscopic pieces of carbon off but i think physical removal of the carbon is the only way to properly fix it. BMWs have been getting walnut blasting services for a while.

i'll bet the intake ports of that head are cakey

 

 

I'm guessing a oil catch can won't do anything?
I'm also sure you saw some oil or blow-by in the charge-pipe and intake tubing when you pulled them apart.
I've seen some in mine; cleaned it out and a little worried of it acumulating in the intercooler, since it is the lowest point of the intake system.

This was from 5-7k miles; (blow-by) the result smells like burnt oil, fuel, carbon, & water (probably from condensation) all mixed together.
Normally this stuff would flow from the PCV into the intake through the valves and finally to the cylinder.
Would love to snake in a endoscope to see if a oil catch can does anything to prevent carbon buildup, but I'm only at 25k.

 

^Great input.

I'm currently designing a catch can for our engine. The biggest set back is the head breathes in 5!!! places. All of it is metered air.
I have seen oil lining the charge pipe of an 8AR with 1200 miles. The blow by is real.
I have not thought about the intercooler issue, that is a really good catch you made. I will check if there is any build up in one.

Honestly, a well designed catch can (not an Ebay one) is the best option. Seafoam or B12 will help, as will water/meth injection. But the engine needs a catch can.

 

Glad we agree!
Next oil change I'll be checking the charge pipe for any blow-by/oil to see if the occ prevents this.

The eBay cans (what I have installed) are okayish, I added additional filters to them to maximize the distilling effect and they work pretty good.
Out of the box they do very little to collect.
Mishimoto is currently having a sale on their occs but they are still pricey, just less lol.
https://www.mishimoto.com/automotive...html?limit=all

There's another IS200t user in our subforum that had 3 occs intercepting the blow-by.
Unfortunately his car was recently totaled
He also added a bigger external heat exchanger (intercooler) and a 100% running all the time prius water pump to get mad low intake air temps.

 

I would love to see this. Did he post a thread on it?

You have a catch can linked to all the breathing ports or just the PCV? Or the two on the front pipe? I would love pics.

 

This has been an interesting read. I've done years of my own engine work on previous vehicles before and my initial thoughts are, based on what the OP posted that these are 2 60k mile engines with similar carbon build-up....I don't think we can necessarily say that the fuel is the problem at this point.

I saw one member posted that that isn't a lot of carbon build-up. You cant make blanket statements like that for every engine. For this particular 4 cylinder engine which is a fairly typical design of modern manufacturers today using a small turbo boosted engine, I would say that it definitely is a lot of carbon build-up *for this particular engine*. Some engines are more sensitive to carbon build-up than others, and generally due to the tight tolerances within the block and head for the cylinders, it doesn't take a lot for it to start causing problems like misfires or, god forbid, leading to blockage on the exhaust side which could then lead to temperatures getting hotter in the cylinder and those gases acting like a blow torch.

So what is the real cause? What solutions available? Well, I owned a Corolla from about 10-12 years ago and I actually came across a similar issue. The engine had a little over 100k miles and one night while driving normally suddenly I get a misfire in cylinder #3. I tested the injection coils and they were all fine, spark plugs were ok too but they did need to be replaced. Ultimately I was able to clear up that problem by dumping a bottle of Chevron Techron the next time I filled up with gas.

My thinking is that it's just a small design flaw in this highly compact and powerful 4 cylinder engine. Is there some way to fix this flaw? No not really, perhaps the next engine Toyota designs they might try to better account for this stuff. But for existing owners right here and now, dumping some Techron or Seafoam in the tank every 10,000 miles should work just fine.