Got this from
another newsgroup. Could be the answer to Rotary plug fouling when using 100LL
exclusively. Use care though, new stuff often has unexpected outcomes. You
know?
-al wick
Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5
N9032U 200+ hours on engine/airframe from Portland,
Oregon
Prop construct, Subaru install, Risk assessment, Glass panel design info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html
As promised,
I’m reporting back on fuel additives.
I have spent a lot
of time over the last six months researching most of the additives used as
ingredients in fuel additives and quite a bit of time doing engine testing.
I used an air cooled, low compression, fixed timing magneto ignition engine for
tests. I removed the cylinder head after each test and took digital
pictures of the head, piston and plug. I only used 100LL as fuel.
Here are my
results; on some things I can’t get too specific because they have become
proprietary.
Starting at
the simplest additives, here are the ingredients of Marvel Mystery Oil. I
shall call it MMO as an abbreviation.
Hydrotreated
naphthenic oil
Paraffin oil
Oil of Wintergreen
(methyl salicylate)
Red dye
This stuff was
invented, as the bottle claims, in 1923. Back then engines were rather
primitive and so it this mixture. The active ingredient is the naphthenic
oil; the rest is just for dilution or to confuse the opposition. Naphthenic
oil was used originally as a low cost “once through” oil in IC
engines or compressors with either no recirculating oil system or a poorly
operating one. The oil has marginal oxidation resistance so it is rapidly
degraded and can only be used in once through systems.
In my engine
testing it left the combustion chamber looking sooty. Subaru engines
operate hotter so it probably burns off this soot, so this is probably less of
an issue. The best benefit that could be obtained is valve guide
lubrication and upper cylinder lubrication. At 4 ounces per ten gallons
it is not very economical.
Next in line
is a whole slew of solvent based brews used as clean up additives. These
use toluene, xylene, trimethyl benzene diluted with paraffin oil and solvent
naphtha. Simple amines are used sometimes, as in Redex.
In engine
testing these tended to clean up the inlet valve and fuel injectors, but it was
a slow process.
TCP additives
evolved from this type of formulation. Tricresyl phosphate was diluted
with toluene to make Alcor TCP. This is used to alleviate lead
contamination of spark plugs and exhaust valve seat recession due to the
presence of lead in leaded fuels.
Decalin TCP does
not use toluene, it uses ethylene glycol as a diluent which is far less volatile
and so it is safer to use both from a toxicological standpoint and carrying it
in the cockpit.
In my engine
testing, a high dosage of Decalin TCP tended to leave yellowish deposits of
lead phosphate in the combustion chamber and on the exhaust valve. At the
recommended level of ½ ounce per 20 gallons for Subaru’s the deposits
were negligible.
The next
generation of fuel additives took a quantum leap in performance with the
addition of polyetheramines. This was patented by Chevron in the mid
1980’s, but the patent expired three years ago. Since that time
there has been an explosion of products containing this additive.
I had a lot of
trouble getting hold of the raw material polyetheramine since the manufacturers
are picky about who they sell it to; but finally, in the interest of bringing
you the very latest stuff I persevered (walking ten miles into the wind through
three feet of snow uphill both ways, bring on the violins) and then I put it to
the test.
I first
“dirtied up” the engine by using a high dosage of MMO.
Then I added a bit
of polyetheramine concentrate to the fuel tank and ran the experiment
again. The effect was remarkable. The combustion chamber and
piston were very much cleaner. I could not believe it and ran the
test again.
I then ran a
whole series of tests, comparing and mixing with Decalin TCP, MMO and other
fuel additive brews that I bought at the auto store.
I used a great
many head gaskets in this testing and the local supplier must be wondering what
I’m up to.
The bottom
line is that I am reformulating Decalin TCP to include polyetheramine.
This will make it a super product and I will call it Decalin TCP Plus.
The price remains the same.
Also, I will
bring out a separate product called Decalin DeeCoke for combustion chamber,
fuel injector, inlet valve and inlet manifold cleanup. This stuff is so
good that you only have to use it once every 50 hours by dosing at 5 ounces per
10 gallons. It will be in a 16 ounce bottle, priced at $11.95.
You can use it at
a maintenance level of ½ ounce per 10 gallons at fill up and then you would not
need the 50 hour dose. High dosage has no detrimental effect on the
engine that I could see, and other manufacturers report the same thing. The
ingredient is on the EPA list of approved fuel additives. It can be used
in cars also.
It will be a
couple of weeks or so before I can get bulk supplies delivered to make these
new products, but if you are interested in this product please let me know.
Chris
Lowery