Water De-coke

[Volvon]

The car has been driving me mad recently losing power so easily on hills and under load that caused stuttering and would force me to drop a gear or even two gears if going up a hill with something in the back!

So thought to hell with it, I'll try the water decoke method.

I fixed the flame trap at exactly the same time as I did this video and then went for a drive so I CAN'T BE SURE this actually even done anything to be fair! But it did stink, and produced a lot of steam so it done something.

The car drives wonderful now, no more dropping gears needed and it has not stuttered/hesitated once on hills or whatever. But again, it could of been the blocked flame trap causing the problems all along...

I will keep an eye on engine run-on and see if it has lessened any and report back my findings.

Video to come here in 5 mins..currently uploading and I've got painfully slow internet.

[grin factor]

Sorry for being a bit fick, but whats a water de-coke?

[Volvon]

Basically I removed air intake, and sprayed water straight down the carb. This water atomises and turns into steam and is meant to clean carbon and crap from engine. I done this process twice. I didn't use a great deal of water, maybe half a pint to a pint at most. I think I will do it a little and often rather than one big session which I think could break something or hydralock as they say.



Its basically like water injection only your stood still

[Clifford Pope]

It works really well but you need to take great care and know what you are doing.
In my experience a very small amount of water works - about as much as you get from briefly dipping the thin rubber vacuum pipe under water for half a second, repeated once. So about half an inch from a jam jar, if that. Engine hot.

I then turn off immediately and let it cool down while the steam gets to work softening the coke in the cylinders. Then fit new plugs and start up and rev it to clear out the gunk.

I don't think it is worth doing again. It works to clear out a lifetime of built up carbon, but if the engine cokes up so quickly as to need doing again then it is using a lot of oil and is probably on its way out anyway.

[BigGreenThing]

This is really interesting stuff. I have been considering doing a water de-coke myself based on replies on an earlier thread I put up on compression checks.

Volvon - did you have any kind of compression reading prior to doing this work at all? Would be good to know what is now also. How's the engine running now?

I think de-coking in this way is not totally without risk (to the engine), but definitely one that seems least damaging and with good results.

I definitely want to give this method a go. The one question I have is where exactly do you put the water in? My carbed car has a great number of pipes in/around/under the inlet manifold!

[Volvon]

I've got side draft carb so I put mine in here:

DSCF9045-copy.jpg

I used a pressure sprayer with a lance and it was a piece of cake. As mentioned I used only small amounts of water, not much water comes out of the lance, but even so I still done it 'spray a second, off a second' with the trigger. The engine never laboured much at all and certainly never bogged down.

I didn't take compression measurements or anything, just squirted and went. I went for a run afterwards and the car feels massivley better, but as I say it could be more down to flame trap than this. It did stink when I done it though, a sort of smell not dissimillar to a clutch burning and/or a seized brake caliper burning smell, but a bit more carbony. If that makes sense.

I'm no expert but in my opinion as there are water injection systems out there and you can happily drive a car with headgasket gone leaking water in, there isn't really a huge risk. Plus their is water vapour in the air hence why you have that condensation dripping out the exhaust pipe anyway so really water going in the engine isn't as crazy as it sounds.

As you use a small amount of water and it atomizes and turns to steam, it is highly compressible so doesn't really stress anything. Obviously people who are daft and attach a garden hose are the people the stories about hydralocking etc come from.

After I went for a little run, when I returned and switched the engine off, it didn't run on, 9 times out of 10 it DOES run on, but there is always those rare times it doesn't run on, so I can't claim it has cured that until i use the car a bit more and test the runing-on status in real world tests. It was the running on issue I wanted to cure more than anything that is why I done this water de-coke.

[BigGreenThing]

Cheers for the photo! So from your photo - it looks like you took off the whole air inlet (think that's the right name for the thing that sits on top of the carb, and sprayed directly into the top of the carburettor? My carb (Solex Cisac) is a top facing one, so I guess I just drip water from a pipe that feeds into the top of the carb (if it's one I can air sucking in)....or drip water into the top of the carb itself? I must have another look under the bonnet to understand what is what...

It'd be interesting to know how performance holds up! Keep us posted!

[foggyjames]

I did this on my 360 (with the Solex CISAC), and works a treat. I fed it perhaps half a pint of water over a couple of minutes by having a friend hold the engine at around 3000rpm, then dipping a vacuum hose in and out of the water every few seconds...usually withdrawing it as it starts to mis-fire, then replacing it once the misfire has cleared.

cheers

James

[chesters6]

you used to do something similar with redex ,strangely though the effect mentioned on the bottle never seemed to happen in reality

[Volvon]

I have had no run on as yet, but I'm not counting my chickens before they've hatched.... it was most evident after a long drive which I have yet to do.

Car still driving perfect no stuttering, loss of power or anything.

BigGreenThing yep I just removed air intake and put water straight into carb. I didn't use vacuum pipes or anything just sprayed it straight in.