De-carboning with water...

[AndrewMac]

I was talking to one of my favorite old crusty mechanic friends. I related to him an incident that happened to me several years ago when one of my Saabs had a head gasket go. I realized it and shut down before it shelled the head.

I was amazed to see how clean the pistons and valves were on the 2 cylinders that took on water. I replaced the head gasket but did nothing to the head or valves save having teh head planed. Didn't even replace the plugs..Damned if that Saab didn't run like a new car.
Rightly or wrongly I have always attributed a large part of the improvement to the affect the water had on removing the carbon deposits. I concede the engine might have been ailing for a time and I failed to notice over the course of gradual decline...but no way did a head gasket alone induce so much improvement.

Then my old friend told me that WWII vintage aircraft were fitted with special injectors on the radial air cooled engines to inject water just prior to shut down and that pilots were trained to do this as part of the operation protocol. The idea/observation was evidently it kept the engines clean and at peak power output.

This begs the question as to whether older mid to high-mile Porsche engines might not benefit from pouring a bit of H2O down the hatch. And is this better or worse than a can of Techron periodically. Anyone else have anecdotal or direct experience with the water procedure for a Porsche?

[Early_S_Man]

Andrew,

I never heard of the water injection on shutdown feature, but the majority of USA WW II engines had water/alcohol injection systems that were activated at full-power settings ... both supercharged and turbocharged engines, V-12 and radial!

[slammed1000]

dont forget the nitrous oxide that they used for a added boost of power in the ww2 planes.....

[cstreit]

Yup, old hillybilly horespower trick I learned a long time ago. Fill a squirt bottle with water, rev the engine and squirt in copious quantities. Plenty of starting fluid on hand in case the engine stalls.

I did this on an old car and it was MUCH better. You wouldn't believe the black sh@#$ that came out the exhaust.

Basically according to a mechanic friend of mine, the water superheats to steam and scours the pistons and valves clean...

[Steve W]

Sure works to keep the motor clean. I have water/methanol injection into my SAAB Turbo which activates at boost, effectively steam jetting out any and all carbon, not to mention the side effect of allowing me to run 30 lbs of boost. There is virtually no carbon on my pistons, heads, or valves.

[A Quiet Boom]

Yup, as Chris so put it "old hillbilly trick" but let me tell ya, some of those old hillbillies will amaze you with their ability to tune an engine without diagnostic equipment, like timing lights. Water injection has been around a long time as a detonation suppressant as well as a quick way to decarbonize an engine.

[82SC]

can someone write a quick DIY procedure for a 911 engine...

my car is apart and i've noticed a good mount of carbon on the pistons heads...I'd like to clean her up...

MJ

[A Quiet Boom]

Originally posted by 82SC
can someone write a quick DIY procedure for a 911 engine...

my car is apart and i've noticed a good mount of carbon on the pistons heads...I'd like to clean her up...

MJ

Solvent like Toulene or kerosene and elbow grease!

[82SC]

well I ment the engine is apart as in my cams are being switched out...but peering into the spark plug hole I see some carbon deposits...so once I get her put together I'd like to try this water trick...

MJ

[72SMFI]

My ol wrench told me about this too. He was the man had also turned me on to Kendall motor oil Sweepco gear lube and MFI early S engines He also new everything about old Ford tractors he mentioned that water trick to me when I was having trouble with a Ford pick up. I would love to give it a try in my 72S , but I got to say, he never said try it in a Porsche motor. I say somone else try it and tell me how it works!! Wayne

[tobluforu]

I do it before every tune up. All sorts of black crap comes out of the exhaust. I've been doing it for 20 yrs or so on every car i have had except my saab which also has water injection. But, i can in no way hit 30 lbs of boost. What the heck are you running in your saab anyways to hit 30lbs? That's way up there..

[Steve W]

It took me years of experimentation to figure how to get a SAAB Turbo to hit 30+ lbs of boost reliably. Now I am going to give you all my secrets in a few sentences. First off, I ditched the factory APC system and am using a HKS Electronic Boost controller to dial in the boost. I loaded an additional spring on the exterior of the wastegate because I found exhaust manifold backpressure was popping open the wastegate valve prematurely. The stock turbo is capable of producing that amount of boost, but a larger compressor section would be more ideal. I modified the distributor's advance, retard mechanism to provide additional ignition retard in high boost situations, by grinding away some of the limit stoppers with a Dremmel. Each degree of retard allows you to run 1 additional lb of boost. I modified the stock fuel pressure regulator to increase fuel pressure from 36 to 60 psi by compressing the overall body slightly, increasing the tension of the spring inside. You need to increase your fuel pressure, otherwise, stock fuel pressure of 37, minus the 30 lbs of boost pressure that's in your manifold working against your injector equals a net fuel pressure coming out of your injector to be ???? Next, I added a 450cc fifth fuel injector from a old Volvo mounted on the intercooler pipe between the intercooler before the throttle body. Because my heads were ported and valves reshaped, the stock 230 cc injectors were way incapable if delivering enough fuel with the extreme increase in airflow. The additional injector pulse synchs with the stock injectors through a transistor circuit tapped off the stock injector wiring above 8 lbs of boost. All this alone will allow your car to run up to 20 lbs of boost on a normal day. If I had to do it all over again, I would have just changed my injectors to some 350-400cc injectors and reprogrammed the chip, now that I know how to read and reprogram the ROM in these Bosch computers.

Finally to hit 30 lbs of boost without predetonation, four additional 230 cc fuel injectors were mounted on the intake manifold about 4" behind the stock injectors, which inject a 50/50 mix of methanol and distilled water into the motor above 13 lbs of boost. These also synch with the stock injectors. Water and methanol have the benefit of immensely intercooling the intake charge, and raising the fuel octane, preventing pretonation. Methanol adds power to the mix to offset what pure water would cause a slight power loss. My windshield washer tank is used to store the methanol/water mix and a Flojet pump regulated at 60 psi is used to inject the mix.

The torque that my car produces is unbelievable, I keep up with crotch rockets and outran a brand new 911 Turbo. The look alone on the guy's face was priceless, man he was pissed. I couldn't stop laughing. But, I have blown 3rd gear 3 or 4 times because the sheer torque caused the teeth on that gear to shear off.

[BYantzer]

Originally posted by Steve W

The torque that my car produces is unbelievable, I keep up with crotch rockets and outran a brand new 911 Turbo. The look alone on the guy's face was priceless, man he was pissed. I couldn't stop laughing. But, I have blown 3rd gear 3 or 4 times because the sheer torque caused the teeth on that gear to shear off.

Ouch, that must get expensive!!

[tbitz]

"You need to increase your fuel pressure, otherwise, stock fuel pressure of 37, minus the 30 lbs of boost pressure that's in your manifold working against your injector equals a net fuel pressure coming out of your injector to be ???? "

Steve, i've noticed on the fuel regulators a hose which is connected to the intake manifold. This hose "reads" the manifold pressure and automatically compensates for decrease (or in your case increase) in intake manifold pressure. This way fuel injectors inject the same fuel regardless of how much pressure they have to go against in the intake manifold.

The reason to increase fuel pressure is just to get more fuel since you have a turbo engine that needs more fuel.

[Steve W]

tbitz, you are absolutely right. I completely forgot - its been almost 9 years since I last played with my car.

[Langers]

I have a friend whose car (Suzuki Swift) is absolutely FULL of carbon (it diesels after shutdown). It runs CIS, and in some of the places I have read about this water method it states that it is for engins with carbs only. Is it possible to do this with CIS? Do I just use a spray bottle after the air filter? Any other tips? Hot or cold engine, revs etc?

Thanks in advance.

[Mark McClure]

I have also heard of this on turbo engines. My Dad is quite a knowlegable guy and I mentioned this to him. He used to do this by misting a spray across the air intake of race bike engines...BSA and Norton. He also mentioned using WD40......Spray this down the intake and rev like hell...it will blow a lot out of the carbon right out the exhaust. Suposidly WD40 has a lubricant in it that assists as well as cleaner which gets rid of the carbon.

Cheers

Mark......

[john70t]

Unbolt the catalytic converter before if possible, that's a lot of material.

[Langers]

So does this work for cars with injectors?

[IROC]

Originally posted by Langers
So does this work for cars with injectors?

I did it on my old Toyota 4Runner. Since the engine wouldn't run without the AFM hooked up to the throttle body, I simply removed a vacuum hose at the throttle body and metered the water in right there. Could probably do the same thing on CIS.

I had about 195 psi compression on all cylinders (and was getting detonation as a result) and the water trick reduced the compression to around 180. Worked like a charm.

Mike