De-coke of Agas Engine

[Old Koreelah]

It means that I've not used it in a Jabiru, if I ever owned one, I would use it.On that note...how does the inside of your Jab's top end look after using it?

Too early to say. (I spend far more time tinkering than flying, so it'll be a while before I get enough hours up.)

 

 

[Paul davenport]

I have used the Subaru cleaner when servicing their engines . Subaru seem to suffer from coking of the valves amongst other things,this cleaner softens and removes this coking providing you use it at every service. It can be verified if you use a vacuum guage and do a before and after test, the after test will show a higher vacuum reading indicating the valve backs have been cleaned and air is flowing more efficiently into the combustion chamber. Customers have commented that their cars ran better after the treatment and used less fuel. I have never had the opportunity to remove the heads after treatment to visually confirm the product, but on balance the customers are happy and that's good for every one. I have soaked a piston in the product and it certainly removed the carbon on it . Tried it on the Victa 2 stroke mower worked on that ,it certainly didnt do any harm

 

 

[spacesailor]

After using it on my 6 cylinder ford motor, the head and valve stems were very clean, Why take the head off?.

 

I dropped a valve when changing the valve-stem seals, tried every thing to get that valve, even to inverting the engine by two people holding it & tipping it over,

 

Very heavy and me lying on my back under it, poking with anything I got my hands on. It seemed a good idea at the time, in-situ half hour decoke!

 

spacesailor

 

 

[bexrbetter]

[ATTACH=full]48302[/ATTACH]

 

The pictures depict plug heat range, someone has incorrectly labelled them as being mixture related.

 

The left is way too hot a plug, showing heating all the way down the threads, the center is way too cold (and fouling) with not a single thread having been heated, and the last is indeed "optimal" showing more than 2 and less than 4 threads having been heated. The same engine with the same fuel mixture ratio would have been used for this demonstration.

 

If you do not read the threads first then you are wasting your time.

 

Coking on air cooled engines is primarily caused by early rich running (oil and fuel) for too long on an engine that takes a long time to come to ideal operating temps.

 

 

[facthunter]

The left plug has overheated. Even shows on the plating of the body of it. People go silent when I bring up the subject of what heat plugs to fit. It's not enough to just fit the makers recommendation without any follow up analysis of how they are working. In a Corby starlet which is slippery the motor is not loaded as much as it would be in a slower more draggy plane. If you run at high throttle openings at low altitude you are getting horsepower out equals HEAT as well. Slower forward speeds as when climbing changes things too. Plug ceramics self clean by reaching dull red heat. If they overheat, the engine will almost keep going with the ignition off, as they act as glow plugs. This gives uncontrolled firing of the mixture and possible severe engine damage, as it will fire before the spark happens. In my view it would be better to run a slightly cooler plug where you engine is working harder than run the risk of engine failure. Jabiru have always stressed the importance of not overloading the motor. (too much pitch, blade area or diameter). It's like running a vehicle with too high a top gear. If you run cooler plugs and overdo it you might get plug fouling with long taxi times, as that's when they soot up if they are going to. Short time at full throttle and they clear the soot coating . If the engine's sick and there's oil involved that may not happen so readily as you might have a "cold" cylinder. As you commence take off roll, always check engine revs, AND MP etc if a C/S prop. It if it doesn't reach normal power indications straight away abort the take off, and have it rectified. Nev

 

 

[old man emu]

Bex,

 

I'm not disagreeing with what you said, but you should have read the caveat in my post:

 

Using the colours of the deposits on the plugs in the attached photo, which colour is closest to the residue on your heads? (Disregard the labelling at this stage)

I was only using that picture to get at a colour reference.

 

OME

 

 

[bexrbetter]

I was only using that picture to get at a colour reference.

Wasn't having a go Mate, merely offering some information for the Plebs.

 

 

[old man emu]

Wasn't having a go Mate, merely offering some information for the Plebs.

OK