[SS-Traveller]

Originally Posted by satish_tns

I had been pushed to do engine decarbonization every 10k km...

That's absolutely ridiculous, and downright cheating. Please report the service centre to MSIL through email.

Originally Posted by satish_tns

Can someone tell me whether to stop doing engine decarbonization from this 60k km service onwards...
I do 65% highway driving and 35% city driving and this city driving is 25% bumper to bumper traffic and 75% open strech with less traffic.

Given
- your kind of driving pattern,
- provided oil changes are regular and of good quality, and
- provided that nothing goes wrong in the fuel system & injectors that might cause unusual buildup of carbon inside the engine,
decarbonisation is not required for the lifetime of a diesel engine - which can well be 2.5-3L km.

[RM2488]

I had a go at decarbonising an engine- my carburetted Honda Unicorn was the victim for the experiment.

It has covered ~35K KMS in the five years I have owned it. Always synthetic oil at 3000 K, proper setting of fuel-air mix. It performed well, always started with just a touch on the self, and the PUC readings were ok.

It all started when I recently checked out another Unicorn that my friend bought an year back. Now it has 6k on the Odo. What got to me was how peppy the engine was. Don't get me wrong, my engine was quieter, but his engine simply had a smooth pickup that mine lacked. So I started thinking... I had new plugs, the carb had recently been cleaned, the oil had been changed. The chain was perfectly tensioned. What then?

I decided to give decarbing a try. I went with the inject-water technique to "steam clean" the engine. And it worked!

While the pickup has not changed much, the engine hardly hesitates like it used to, and has become even quieter! The biggest benefit being how SMOOTH it has become. It is as smooth as the day I bought it- next to no vibrations!

I'm thinking of trying it on my 88K run Ikon, but the high mileage makes me a bit wary. Will keep you guys posted if I do.

[saket77]

Originally Posted by RM2488

I had a go at decarbonising an engine- my carburetted Honda Unicorn was the victim for the experiment.

The experiment looks interesting. Would be nice if you could share the process with us. I may be the next in line

[RM2488]

Originally Posted by saket77

The experiment looks interesting. Would be nice if you could share the process with us. I may be the next in line

The theory is that the water, when it hits the hot cylinder wall, changes phase explosively to steam, producing a small shockwave that dislodges the carbon.

The process itself is simple. What you have to take care of is the quantity of water you pump into the engine- this is somewhat riskier than the common fuel+cleaner method. But only if you're careless. Excess water in one go will almost certainly hydrolock your engine, leading to a nice bent rod and a long bill.

The basic idea is to introduce a small amount of water into your cylinder while the engine is running. The only way I see with a carburetted motorcycle engine like mine is to bypass the air-filter. I used a small bottle sprayer to introduce only small amounts of water at a time. Doing it on a fuel injected car has two possibilities. One is to bypass the air-filter. The other is disconnecting the brake assist vacuum line to draw a small amount of water. I have not yet tried this on my car.

The steps I followed were thus:
1. 15-min engine warm up. From what I've read this cannot be skipped.
2. Increase idle to around 3-4K.
3. Remove the air filter. Use a small sprayer bottle to spray water into the intake. The engine will choke and sputter a bit. Using a sprayer bottle, it is almost impossible to hydrolock your engine. When the revs rise, hit it with the spray.
4. It should take you around 25 mins to empty a half liter bottle of water. There's no point in going too fast.
5. Let it idle for another ten minutes before dropping the idle to your normal 1200-1400.
6. Take it out for a 15-min drive or so before you switch off the engine. You're done!

I did notice a weird plastic-type burning smell, and steam coming out of the tailpipe while I was injecting.

I can assure you that the effects (smoothness, no hesitation) were worth the effort, and they were not a placebo. However, I am not sure how long they will last. But for now, it feels pretty good. Once I am entirely certain I will definitely try it on the Ikon.

[saket77]

Thanks RM2488 for sharing the method. I had read about using water to decarbonize the engine but you put up the entire procedure in layman's languague. Appreciate it

Probably will give it a try on a day when my instincts are positive

Regards,
Saket

[FlatOut]

Originally Posted by saket77

Thanks RM2488 for sharing the method. I had read about using water to decarbonize the engine but you put up the entire procedure in layman's languague. Appreciate it

Probably will give it a try on a day when my instincts are positive

Regards,
Saket

Steam or water injection are both excellent techniques, if used correctly. Be aware you can wreck an engine very quickly if you get it wrong, though!

Another technique, more for prevention than cure, is the addition of 0.25% acetone in the (petrol) fuel tank, or 0.15% in a diesel car. You will find performance improves as well as economy.

If there is a problem with the engine, then sort that out first.

[saket77]

Originally Posted by FlatOut

Steam or water injection are both excellent techniques, if used correctly. Be aware you can wreck an engine very quickly if you get it wrong, though!

Another technique, more for prevention than cure, is the addition of 0.25% acetone in the (petrol) fuel tank, or 0.15% in a diesel car. You will find performance improves as well as economy.

If there is a problem with the engine, then sort that out first.

Thanks FlatOut for the technical information on the ratio. However, all these suggest that there does exist a market for de-carbonising engines. Although my car has been de-carbonized at regular intervals, at the back of my mind I always think that long drives and some high throttle inputs would clean the carbon deposits. Don't really know how much that helps, would be interested to know what the forum thinks about it?

Regards,
Saket

[sgiitk]

I find that going on a highway and opening the throttle for about quarter to half an hour will decoke all car engines in a reasonable condition.

[Gansan]

My two-stroke bikes used to be de-carbonized from time to time, as a matter of routine during service. In contrast, my four stroke Splendor never. Not even once in 104000 KM, before the engine was opened for a rebuild. Not only the engine, the silencer too was never decarbed..

Good fuel and oil, timely oil changes and services are the key. And as @sgiitk mentioned, revving freely on the highway for a while, without over speeding. I find a speed of ~ 70 KMPH and ~90 KMPH, sustained for a few KM uninterrupted, to be best for my bike and car respectively.

[SS-Traveller]

Originally Posted by saket77

...I always think that long drives and some high throttle inputs would clean the carbon deposits. Don't really know how much that helps...

Originally Posted by sgiitk

...going on a highway and opening the throttle for about quarter to half an hour will decoke all car engines in a reasonable condition.

It's referred to as the Italian tune-up. More information at these links:
http://en.wikipedia.org/wiki/Italian_tuneup
http://books.google.co.uk/books?id=t...eup%22&f=false

[saket77]

Originally Posted by Gansan

My two-stroke bikes used to be de-carbonized from time to time, as a matter of routine during service. In contrast, my four stroke Splendor never. Not even once in 104000 KM, before the engine was opened for a rebuild. Not only the engine, the silencer too was never decarbed..

Good fuel and oil, timely oil changes and services are the key. And as @sgiitk mentioned, revving freely on the highway for a while, without over speeding. I find a speed of ~ 70 KMPH and ~90 KMPH, sustained for a few KM uninterrupted, to be best for my bike and car respectively.

Hey Gansan,

Good to know that your splendour clocked the magical 6 digit figure! However, the 2 stroke engine burns oil with fuel as they don't have a dedicated lubrication system. That accounts for more carbon deposits. Also, the modern 4 stroke engines burn fuel much more efficiently than the old 2T engines, hence less carbon deposits in the system.

I think that the inherent design of 2 stroke engines, which do not have valves (but holes on cylinder for intake & exhaust), it has a tendency to expel un-burnt fuel or fuel which has not been combusted fully.

Regards,
Saket

[Gansan]

During my two-stroke bike days, a racer/mechanic friend used to say doing a few high speed runs on a free road, once in a while will clean the carbon build-up. They will still need a decarb, but not so frequently. He said most two stroke silencers were designed in such a way (especially after the bend from the engine where it straightens out) to create a forced suction / turbulence in the exhaust gases, and the faster you run, the more powerful this scavenging will be, sucking out the carbon.

I don't know if this is true of four stroke silencers, since the smoke is not visible. But if you watch the Yamaha or Shogun silencers closely, you can see the smoke come our with a swirling motion.

[FlatOut]

A few years ago I towed a racing car on a trailer, with my Mercedes 300TD, flat out for about 500 miles. I hadn't long been running on vegetable oil and so when smoke came out of the tailpipe about 30 or 40 miles into the journey, I assumed it was the driving flat out, and/or the use of veg oil for fuel. I slowed a little, then since all seemed well and rhere were no extra noises or smells, continued with my foot to the floor - we were a little late, on our way to a 24 hour race.

When more smoke billowed out of the exhaust all of a sudden (usually there is none) another 10 miles down the road, I thought the engine was probably damaged - after all, it had covered over 400,000km. I slowed more, expecting something to start rattling, but all seemed well so gradually I increased speed back up to max.

When the car was unloaded and the trailer unhooked, it went like a rocket, perhaps another 10% power - very smooth, too. I have since discovered that plant oils are very cleaning of the inside of an engine - it is probable that the heat and different fuel burnt off some heavy deposits which had been laid in the combustion chambers or pre-combustion chambers for many years.

Additionally, the injectors and valves would have been cleaned in this extreme version of the Italian tune-up. The car and its engine are still running beautifully to this day.

[ron_9191]

Is there any place in Bangalore where you can get the car cleaned up like this? If yes please suggest, my car badly needs it.

[ASVA]

Hello Team

Called up the Toyota Service centre where I get my Innova regularly serviced to book 50k kms service.

Spoke to the SA with whom I share a good rapport. Asked him if decarbonising is necessary for my diesel Innova. He said that as long as the engine oil has been changed at recommended intervals and the car is serviced as per schedule, there is absolutely NO necessity for any decarbonising for any modern diesel engine and also said that Toyota itself doesn't recommend it.

It was good to see that the service centre and Toyota are not fleecing customers in the name of such unnecessary procedures.

Regards
ASVA