Fuel Additives

·         John Ruffe

·         Topic Author

·         Offline

·         Posts: 3

·         

·         

It is not uncommon for fuel additives to be used in some Lycoming and Contenental engines to reduce the occurrence of sticking valves from lead and other deposits and to reduce carbon build up on valve faces and seats. It is my understanding that the manufactures approve the use of specific products. Why does Jabiru so strongly discourage the use of upper cylinder lubricants in their engines?

Please Log in or Create an account to join the conversation.

John R.

·         Doug Smith

·         

·         Offline

·         Posts: 287

·         

Hi John,
In general it's a question of the best use of engineering resources - for Jabiru to approve an additive we must be sure that it will work as it is designed and will not cause any harm in any Jabiru Engine in any form of operation. This is not something that we can just accept based on spec sheets or reports from one or two operators: it has to be thoroughly tested and verified under controlled conditions. Given the number and variety of additives available on the market the engineering effort required to approve even a selection would be prohibitive and not time effective for the (likely) small improvements gained.

Of course it's likely that many additives are harmless BUT we have had experience with several that have done real harm to the engine very quickly so the general advice for people is not to use them.

Regards,
Doug.

Please Log in or Create an account to join the conversation.

·         Pete Mullooly

·         

·         Offline

·         Posts: 4

·         

·         

·         

I started to use a product called Dekalin which i added to my avgas,bought this at Oshkosh .But i have now started to use Power-Up which i add to my oil.Did an oil and filter change and added the required amount 90 mils of Power-Up as recommended,I have found that my cylinder head temps have been reduced to a more acceptable limit.It also reduces ring and valve gum build up and aids in a better start,as well as leaving a film on the cylinders thereby reducing corrosion to the cylinders.I will be keeping a close eye on the engine parameters to further my satisfaction on the use of this product,but happy so far.Engine is a 2200A serial num 22A1642. Has been fully rebuilt at 514 hours having to fit a new crank and the new fly wheel as the previous original one could not be balanced?? Regards Pete M

Please Log in or Create an account to join the conversation.

·         Doug Smith

·         

·         Offline

·         Posts: 287

·         

Hi Pete,
Glad to hear it's working for you and that you're going to keep an eye on it longer term.

I recently tried a friction reducing additive in the gearbox and differential of my ute and after 10,000km the gearbox oil was fine but the diff oil looked black and smelled burnt. It was interesting that the results were so different even with the same additive in the same oil - and it's effects like that which make us cautious about using any additives in aircraft engines.

Not being able to balance the crank/flywheel seems strange - they're balanced during manufacture and don't usually change much.

Regards,
Doug.

Please Log in or Create an account to join the conversation.

·         Pete Mullooly

·         

·         Offline

·         Posts: 4

·         

·         

·         

Further to Power-Up a mate of mine who is a small engine mechanic has been using Power-Up in his 80 HP rotax for a number of years now the engine having done in excess of 2300 hours and has to date not had a major upgrade,must be doing something for this additive.

Please Log in or Create an account to join the conversation.

·         Tommy

·         

·         Offline

·         Posts: 2

·         

Knew a guy who swore that adding a cup (about 250ml) of engine oil to every tankful of fuel (petrol) for his car extended the life of the engine and reduced fuel consumption. I don't know whether his claimed consumption could be believed, since it seemed too good to be true, but his cars all did over 500 000km before he sold them......................

The above gave me this crazy idea: Since burning oil in the cylinders will definitely cause some carbon buildup in the combustion chambers, not to mention increase air pollution through the exhaust gasses, how about adding a very small quantity of two stroke oil, which burns more easily and leaves less residue, to MOGAS? Will this not increase the anti knock properties of the fuel? There is of course the risk of carbon buildup on the spark plugs, which can effectively cause the engine to die at a very uncomfortable moment.

Please Log in or Create an account to join the conversation.

·         Doug Smith

·         

·         Offline

·         Posts: 287

·         

Hi Tommy,
The old "add some oil to your petrol" trick has been floating around in one form or another for years. It was pretty big amongst the dirt bike community a little while back - I must admit I've always been a bit of a skeptic.

If you're using AVGAS the lead is a great upper cylinder lubricant so oil isn't needed. Plus oil in the fuel will actually decrease the octane rating: Excess oil being burnt in the cylinders is one of the classic causes of detonation so it's definitely not a case of more = better. Bearing in mind that, being a horizontally opposed engine without valve stem seals, you'll be burning a bit of engine oil already, I can't see it being particularly beneficial.

Regards,
Doug.

Please Log in or Create an account to join the conversation.

·         Pete Mullooly

·         

·         Offline

·         Posts: 4

·         

·         

·         

Hi Doug the reason that the gear box oil was black is that the additive would have removed all the gunge build-up that had formed in the past as this is a common result that additives have of cleaning out impurities.

Please Log in or Create an account to join the conversation.

·         Doug Smith

·         

·         Offline

·         Posts: 287

·         

Hmm, I don't think that's the case. It was the differential oil that went black, not the gearbox. It's not an LSD so there's no clutch material or anything in it. And this particular additive was just a Teflon friction reducer; I've used it a few times before on other vehicles and never seen an effect like this.