I was just informed of a way to clean carbon out of the combustion chamber but it sounds kinda dangerous to me. The deal is you squirt a gallon of water into a vacuum line while the car is running at 3500 RPM. I idea is that the water will hit the rotor, turn to steam, and clean off the carbon. It sounds kinda weird to me because I know if you get water in your intake on a piston engine, it can bend your valves and such. Has anyone done this and was it successful?

 

Search?

 

lots people have done it, some swear by it. but you don't really "Squirt it" in there, you more or less let it get sucked in by vaccume. I think the biggest risk you take is fouling out your plugs cause its not going to CAUSE detonation, but if you get too much in there, its gonna dog out the motor.

Water injection is becomming very popular among the High boost turbo crown as a way to decrease the chance ofm detonation and let you lean out the mix a bit to gain more power. The idea is that the water evaporated on contact witht he cylinder walls cooling them and thereby stopping multi-point combustion inside the combustion chamber (detonation) and to an extent it will also in the hot air air charge to cool the charge and make it denser.

This theory is very sound.. its been around at least since WWII when it was used in fighter aircraft equipped with superchargers to accomplish the same purpose. The Germans also injected Methanol with the mater mix on the ME109 to create more power at the same time.

Now, as far as its usefullness of cleaning the carbon off the rotors.... I dunno. I'd like to see an engine torn apart raight after this procedure to see if it actually works.

 

Yes, this is all true. You can't really hyrdolock a rotary...all teh seals are springloaded so excess pressure would just force around them, at worst you'd just lose compression for a few seconds until the water was cleared.

Water will NOT foul plugs or 02 sensors, btw...as soon as it burns completely away (a few seconds) it's back to normal.

 

"IF" the vac line for the boost pressure sensor only routes to the front rotor, as I've read on this forum a couple of times, I can vouch that the "steam cleaning" doesn't do much for our engines- I broke her down for a rebuild not long after I sucked a gallon of distilled water through that hose, and both rotors were still caked up pretty good with some hard-*** carbon...If it worked, I should have seen one rotor "cleaner" than the other...

 

That carbon took 15-20 years to get installed, 10 minutes is not going to undo all of that. IT would take many treatments done close together (every week, for instance) to make an impact. IT is also very useful on an engine that has been rebuilt, to KEEP it clean from day one, possibly in conjunction with premix.

 

Exactly why my rebuild has been running premix exclusively- to keep it clean...That carbon all over everything was a PITA to get off during the rebuild.

Also, since gas & premix obviously make it past the oil control rings during the compression stroke, and build up in the oil during normal operation, you've got to assume that some of the water injected also makes its way past said rings- who the heck wants water (of ANY quantity) in their lubrication system?

 

where can you get a good water injection kit?

 

some people also had good results with using carb cleaner instead of water. It sounds more effective to me, but i have yet to try it.

 

We can't know for sure, but my guess is that the majority of the gas contamination in oil occurs from combustion GASES that are forced around (think thousands of psi) and not raw fuel getting into the oil. The only time I've seen gas with raw fuel contamination is on severe flooding problems where there was actually gas puddled up...heck, one time I bought a "blown" turbo II that would flood so badly it lost all compression after being shut down for just a couple of seconds. IT also smoked quite a bit. I went ahead and disassembled it for rebuild, and found so much gas in the oil that the rings couldn't keep it from draining into the combustion chamber once the engine shut down. Lesson learned.

I think we're confusing a lot of newbs here. Time to clarify. What we're discussing here is water injection during idle/no load situations (in the driveway) as a means of maintenance, to clean the internals...not for any other purpose. Water injection, as it is commonly discussed, is used under heavy load situations on modified (boosted) applications of all types for detonation control, as water actually lowers combustion chamber temperatures greatly. The water injection method as a means of maintanance (carbon control) is useful only to rotaries, and is not widely accepted even among rotary owners.

For a bit of info, check out my writeup. FYI, I use this on all of my own rotary cars and never have issues with carbon buildup...of course I usually run premix, and change oil at or less than 2000 miles.

http://www.rotaryresurrection.com/ro...injection.html

This was a very big debate when the idea was brought up a year or 2 ago. I have personally never tried it, and probably would not. In my mind, I would rather run 20 gallons of water through my engine in a single day than 1 can of carb cleaner. That stuff is quite harsh, and also leaves behind residue. I'd be far more worried about wear to apex seals and rotorhousings than I would carbon buildup at that point. At least you know that the water will NEVER hurt your engine...harsh chemicals, you do not know how they will react to soft metals and heat/combustion.

 

if you want to see a water injection setup check out this video. it's about 25~26 megabytes but is one of the coolest rx-7 vids i've ever seen on the internet.
http://www.idahorotary.com/rxtasy5.wmv it's long but he shows off his engine and tells a little about his setup.

also might want to ask this guy "RXTASY1" how he did it so you can get some ideas yourself.

 

We are talking about the water cleaning. not injecting water for performance.

 

Whoa took you 4 years and 8 days to come up with that reply!!!!

Edit: it's ok least you have shown us you can search!