Well, Paimon, "visual inspection before and after".

Doesn't have to be a teardown.

 

Right, i generalized when i said teardown.

Now on the flipside of playing devils advocate, i know that using water injection as a form of cleaning the motor is very popular among the RX7 guys, mind you we aren't talking a once a year thing, but more of a once every few weeks thing.

 

I can understand your points. But to my understanding the de-carb made note-able changes in overall smoothness, starting, and driveability which is my book is proof enough.

However since there were no witnesses arguing otherwise it'll just be regarded as bullshit and that the other variables trump any consistent change after the cleaning. IE:^^^^

I'd be willing to give water injection a go.

 

I won't argue with you on that, this engine was toast, they were just trying to milk what they could out of the owner since the car was out of warranty.

And I'm not saying you only work on older 13b's but getting water out of Renesis is substantially different (I would think) than on a REW due to the exhaust port differences. Having water sloshing around inside the engine just seems like a horrible idea.

But at the end of the day without proper testing of any of the methods, it's all moot.

 

Correct. The rate that the engine becomes carboned is an unknown as well, and very subjective to the style of driving I imagine. It wouldn't surprise me to find out that water/meth injection is actually preventing carbon from sticking in the first place, rather than just removing it once it's already on there.

My engine has 15,000 miles on it, which should be sufficient for plenty of carbon. Someone that dailies their 8 would have to pull the plugs for regular borescope inspections to figure that out. I don't drive my 8 enough any more to take that on.

 

The issue is, if everyone believed the "i felt a noticable change after doing....." ... we would all have those magnetic fuel line cleaners, grounding kits, and throwing on K&N intake systems on our cars.

Heck i felt a noticable difference in the way my bladder felt after 4 shakes at the urinal as opposed to my usual 3 ...

edit: again, i am not saying you are right / wrong/ etc .... but as an engineer, i question claims without qualitative results

 

And just to prove I indulge on the juice myself, i have been using FP+ in my fuel system for years now as a means to treat carbon buildup. It has some praise from the BITOG forums, and is one of those "this stuff breaks down carbon to graphite using cyclohexanone" effects ....

now does it work? who knows
do i feel it works? i guess, then again, i dont know what it 'not working' feels like
has it harmed anything? not to my knowledge
am i willing to risk it? sure why not ... at the end if it blows up my engine at least i can say 'dont use this ****'

 

if the water was sloshing around it wouldn't run, although realistically it would do a better job at loosening up the carbon.

the water is vaporized nearly as much as the fuel as it enters the engine and as soon as the chamber fires the water is basically broken down into it's basic building blocks and goes out the engine with the exhaust.

can't think of this as a garden hose in an engine with liquid sloshing around with each cycle. the water would foul the ignition and the engine would not run if that was the case. i have gone a bit overboard at times and stalled the engines, but they always fired right back up ready for more.

i do have a 1974 engine i just removed from a rotary pickup that i decarbed several times, though i didn't inspect it before i did the treatments this engine was also completely locked up when i got the truck, unseized the engine and decarbed it with water about 4-5 times. after removing the engine i inspected it and there was only freckles of carbon inside the compression pockets. no, that doesn't mean it worked but i'm quite sure it wasn't that clean after the engine had sat for 25 years prior without being run.

maybe i will try to get some scientific proof sooner than later with my new borescope to rule that it does help or do nothing. if i can remember the next time i do a decarb and feel like pulling the plugs out.

if it does remove carbon i see it as a good thing, i have seen several engines die simply due to carbon buildup and the 13B-MSP runs a tad rich... heh

 

Wow, you mean my grounding kit does not work? Actually, the kit was less useful than the process of cleaning up the grounds, car did run a lot better though, less hunting at idle.

For the before and after guys, anything come out the tail pipe? I ask because back in the day, my grandfather showed me how to pour water down the carb to do basically the same thing. Differences was a piston engine vs rotary. But, when done, there was a pile of black crap under the tail pipe.

For a renesis, without peripheral ports, I cringe at the gallon of water procedure. We used about a cup, poured in a little at a time. That cup of water generated the pile of crap that came out the back. with today's engines, maybe at most a half liter water bottle through the ports (Jet Air Port anyone?, by far the easiest to get to).

So, show me your crap!

 

I would expect that most people that decarb still have their cats, and catch it all. You didn't have a cat on that older carb-equipped vehicle I'm guessing. Though, even without a cat, our massive stock can catches plenty too I'd bet. It would probably be my problem of showing a pile of crap.

(side note, the grounding kits CAN work, but only as much as new ignition "works" in increasing power of a car with shot coils. It can only improve back to where it should be if the existing ground network is deteriorated, but won't improve better than new. Ground points and wires DO deteriorate over time.)

 

Ah, did not think of the cat... Hm.... Hm.... Not sure I want all the stuff in the cat.... Hm... Hm...

And, yes, it is all about getting back to where things should be. The only real exception is that for the grounds, the star washers really help. That is all I really recommend when people ask. On my 04, all the body grounds were painted.

Still thinking about that cat, and trying to decide if the carbon will come out as dust, or flakes. flakes would be bad....

Must have beer.

 

Decarbing with beer now?

 

H20 to me seems to actually help clean the cat at the same time. the cars not only ran better but also smelled cleaner.

the cat is running hotter than it does under normal circumstances and is being attacked by more water vapor than it normally would. throw dirty plates in an oven and you wind up with burnt dirty plates. throw dirty dishes in the dishwasher sprayed with hot water and you get clean plates.

stupid analogy but they always seem to be true for my testing applications. difference here being it isn't liquid H20 that is touching the cat but more or less a vapor, not like you want liquid hitting a hot catalyst anyways.

 

+1, water would be much less likely to harm a catalyst, is cheaper than cheap, and is less likely to remove/harm the oil being injected versus a cleaner which will strip any oil away.

 

i can't believe you guys are arguing about this? water works, if you've even pulled a piston engine apart with a bad head gasket you can spot the cylinders because they are clean!

and its not a garden hose of water, its a small amount over 20-30 minutes, you actually need the water to turn to steam....

weather cleaning the carbon helps or not is a valid question... before i pull the engine in mine, i'm gonna give it a bunch of water, less cleaning later...

 

you completely missed the entire point of the thread. Re-read and come back. The argument isn't so much 'it works/doesn't work' it is 'how well does it work / where is the proof / how often does it need to be done'. I can guarantee you that one 'steam cleaning' isn't going to get your rotors nice and shiny.

 

And what damage is being done if you were to do it often.

 

and H2O is a normal byproduct of combustion anyways, so i can't envision it really being that harmful unless you could get enough into the exhaust on an already to temp cat that it would shock it enough to fracture it.

i haven't had any cats fail shortly after doing the treatment, long term i can't vouch for though most cats being upwards of 100k miles don't have much life left in them anyways.

 

Before pics taken (about 30 pics per rotor using the leading spark plug port), then half a can (6oz) of seafoam run through the front rotor, and about the equivalent amount of distilled water through the rear rotor. Both ingested with the engine running, with throttle manipulation to keep the engine from stalling.

Currently waiting, letting everything cool down so my borescope camera doesn't melt on the housing taking the after pics.

Why did I use so little? Because it's what is typically done, half a can of seafoam per rotor. I suspect to be really effective more is needed, but this will show what the typical usage actually does so we can tell people they need more, or confirm that it is actually enough. After I take those after pics, I will then run the rest of the gallon of distilled water through both rotors about evenly, and will be taking a 3rd set of pics. If there is significant improvement but still a ways to go, I will continue to see how much water is needed. Seafoam is too expensive to burn through like that

 

i know, i actually did it on my car. the engine is still worn out, but i feel better.

 

https://www.rx8club.com/tech-garage-...arbing-241867/

 

Did this today. Ended up stalling the engine when I had both lines in the water at the same time however, it started up after several cranks. Also got P0300 code and noticed milky residue on the dipstick. Hopefully this will dry up after the drive tomorrow.

Noticed an improvement in vaccum.

 

umm.. my brother was a mechanic for years. He showed me how to do it.

It works on piston engines.

Haven't done it on the RX-8.

I bet H2O is much better than sea foam or another cleaner.

Have you read the ingreients on sea foam?

Not good for the seals.

 

I don't like the PCV setup either. I hope they consider the drawbacks and don't use the same type of setup with the new RX-7.

 

Hello everyone, Sorry to revive such an old post, (3 years later), but i was able to read everything and im really thinking about doing this on my rx8. However the real question has not been answered. Does it really work?. Changing spark plugs for nothing would really suck (i live in overseas, and i have to order the spark plugs online, then they are shipped to my courier in miami and then shipped to my country, which means shipping fees are very high) I understand how in a piston engine with a blown headgasket we will find the pistons clean, but i have seen 13b renesis engine with coolant seal blown and when the engine is opened to install new seals there is a lot of carbon build up on the rotors. But we still remain with the original question. Does water decarb really work for the rx8? If there is any updates I would love to see any pictures before and after. Salutes from the Dominican Republic.