MUCH OF MY
readers’ mail asks
about engine
cleaning. Now I can
finally put that topic
to rest. Tests with
two new products
have shown that either can quickly get rid of the most stubborn muck,
grime, and baked-on “varnish” that model engines acquire, one of
which is the newly reformulated Demon-Clean (DC).
It is now available from BJ’s Model Engine Service (51 Hillside
Dr., Beacon Falls CT 06403; E-mail: [email protected]). The new
DC works as well as the original (which I tested a few years ago and
reported here on the excellent job it did) but has a much longer shelf
life.
The other new product, brought to my attention by Stan Grett
(Enterprise AL), can be found at most supermarkets. It’s Dawn Power
Dissolver (PD), and it comes in a plastic spray bottle.
To test the two cleaners I obtained from a friend a couple grungy
CL engines that had probably never been cleaned. They had been put
away dirty and sludgy and left like that for more than 35 years.
At first I planned to use DC on one engine and PD on the other, but
then I realized I could make a better comparison by applying one
cleaner to one side of each engine and the other to the other side.
That’s what I did.
DC has a mayonnaiselike consistency and comes with a small, stiffbristled
brush for application. PD is less viscous; its spray penetrates
well between cylinder fins, yet it is enough like a gel to be
nondripping.
Both products come with strict cautionary warnings, which I
obeyed exactly. Wear rubber gloves (these products are strong skin
irritants) and safety glasses (you don’t want even a tiny droplet of
either to touch your eyes).
I did my engine-cleaning work outside. DC recommends it
although its vapors are far less pungent than those of the original
formula. PD can be used safely indoors and has a mild, pleasant aroma.
I laid both engines on their sides on a strip of aluminum foil and
thoroughly brushed DC onto one side, including half the head fins.
Two new engine cleaners are thoroughly tested
Also included in this column:
• The new O.S. LA Series engines
The Engine Shop Joe Wagner | [email protected]
Dawn Power Dissolver quickly removed the burned-on oil residue
from this RCV91-CD’s muffler and made it sparkle like new.
These grungy CL engines (from an anonymous donor) made fine
test subjects for two new model-engine cleaners.
The cleaners and their results. Aside from a few oxidation spots,
the engines look nearly new. No disassembly was needed!
Then I turned the test engines over onto their other sides and sprayed
PD on them. After roughly an hour (wearing rubber gloves and safety
glasses again) I used warm water and a stiff-bristled toothbrush to rinse
the engines clean over the kitchen sink.
I learned that DC seemed to be slightly more “aggressive” than PD,
but both cleaners worked exceedingly well. They removed all the
surface sludge with one application. Deeper incrustations, such as
between the head fins and in the cavity around the plug, needed a
second application.
One of the engines had a thick streak of orange paint (enamel, I
think) on its case. All of that came off completely after the second
cleaner-brush-rinse cycle.
Stan Grett had said that PD did a great job on four-stroke mufflers.
The one on my RCV91-CD had some burned-on oil residue, and it
wiped right off after I sprayed it with PD and let it sit an hour. I didn’t
even bother to remove the muffler from its engine; the PD’s sprayer
head projects a narrow, easily aimed stream. In fact, I didn’t do any
disassembly for any of these tests.
100 MODEL AVIATION
12sig4.QXD 10/25/06 11:24 AM Page 100O.S.’s new LA Series RC engines perform as great as they look. They are especially
made for sport fliers and beginners in power modeling.
This O.S. .25 LA-S CL engine started on its second flip and needed only 10 minutes of
break-in time. Notice the homemade needle-adjustment extension.
“What about the water getting inside?”
you may wonder. Not to worry. Some years
ago, when testing for corrosive effects of
water in fuel, I couldn’t generate a speck of
rust in any of six ball-bearing (Fox) engines,
even after spraying water directly on the
bearings. That’s because tap water is pH
neutral, I think.
After rinsing all the cleaners from my two
test engines I used my air compressor to blow
out the water that got inside. Then a few
blasts of WD-40 followed by After Run Oil
relubed the now-clean test engines.
Neither new engine-cleaning product is
quite perfect. Both will remove paint from
parts such as older K&B green heads and
mess up color anodizing. And neither can
clean off surface corrosion, such as rust on
steel and oxidation on aluminum, or wood
chips embedded in the propeller-driver
serrations. (You’ll need a wire brush and/or
steel wool to solve those problems.)
Other than that, DC and PD worked
amazingly well for me, as you can see from
the pictures. (The “after” photo shows my
two test engines as they emerged from
cleaning and rinse-off. No “touch-ups” with
steel wool or anything else have been done
yet.)
The new O.S. LA Series of engines is
instantly recognizable by its “midnight blue”
exterior finish. Made with O.S.’s usual
extreme precision and meticulous attention to
detail, these power plants are available in RC
and CL (called LA-S) versions and in a wide
range of sizes, from .10 through .65. All are
reasonably priced.
I obtained two of the smallest LA
engines—the .10 and .15—and a .25 LA-S.
The well-illustrated instruction booklets that
accompanied these power plants state that
they were “developed to meet the
requirements of beginners and sport flyers.”
The O.S. LA Series seems ideal for that
purpose.
For one thing, the manuals cover almost
everything a beginner would need to know.
They list all the accessories required, even
down to the fuel can and battery leads! They
describe and illustrate glow plug, propeller,
and muffler installation, and even how to fill
the fuel tank. Needle-valve adjustment is
thoroughly explained—and an entire page is
used to do so.
Troubleshooting is covered in detail, on
two full pages. There’s also a “flowchart”
diagram that covers every stage of adjusting
the carburetor. Exploded drawings are
provided that show every component of the
engines, along with their part numbers.
These things may be elementary to you
and me, but not to a beginner! In helping
many youngsters—and sometimes their
parents—get started in model aviation I’ve
found that no detail is so small that it can’t be
done incorrectly by someone who is
unfamiliar with model engines.
The only problem remaining is to get the
new engine owner to read and follow the
instructions. I’ve been messing with model
engines for several decades. Long ago I
learned that it’s always best to read the
instructions, all the way through, first. They
may not tell me anything I didn’t already
know, but there’s always the possibility that
they might.
The LA engines use simple, adjustable airbleed
carburetors that permit the needle valve
to be moved to the rear. It can be safely
adjusted there, two inches or more away from
the propeller.
(A minor but thoughtful feature of O.S.’s
needles is the provision for adding a wire
extension. There’s a precision hole in the outer
end of the needle for that purpose and a
setscrew for gripping the wire.)
Other small but important details that
impressed me in the LA-series engines are the
hardened steel washers between the propeller
driver and the case front and the positive-drive
design of the propeller driver itself.
(The washer prevents possible galling and
wear between the driver and case from
rearward pressure during electric starting. The
positive drive eliminates any chance of
slippage between the crankshaft and the
driver.)
When I first turned them over, the three
LAs felt smooth and snappy right out of the
box. Their instruction booklets confirmed my
feeling that very little break-in would be
required. The booklets also instruct how to go
about doing that in your airplane: just run out
one full tank of fuel on the ground, with the
needle set roughly half a turn rich.
After that you can fly—with a somewhat
rich needle setting that you decrease a trifle
after each flight. By the sixth time up, your LA
will be broken in nicely.
O.S. offers some useful accessories for the
LA engines, such as spinner nuts for easy
electric starting. Beginners are likely to
appreciate O.S.’s predrilled and pretapped
Radial Motor Mounts. Made from aluminum,
they will help cool their engines.
These mounts do cost more than the
molded plastic type. However, they eliminate
the need for close-tolerance drilling and
tapping work that the plastic units require. The
O.S. mounts come ready to use, complete with
the proper-size mounting screws. And unlike
many molded radial mounts, their mounting
surfaces are flat and parallel. MA
December 2006 101
12sig4.QXD 10/25/06 11:30 AM Page 101
Edition: Model Aviation - 2006/12
Page Numbers: 100,101
Edition: Model Aviation - 2006/12
Page Numbers: 100,101
MUCH OF MY
readers’ mail asks
about engine
cleaning. Now I can
finally put that topic
to rest. Tests with
two new products
have shown that either can quickly get rid of the most stubborn muck,
grime, and baked-on “varnish” that model engines acquire, one of
which is the newly reformulated Demon-Clean (DC).
It is now available from BJ’s Model Engine Service (51 Hillside
Dr., Beacon Falls CT 06403; E-mail: [email protected]). The new
DC works as well as the original (which I tested a few years ago and
reported here on the excellent job it did) but has a much longer shelf
life.
The other new product, brought to my attention by Stan Grett
(Enterprise AL), can be found at most supermarkets. It’s Dawn Power
Dissolver (PD), and it comes in a plastic spray bottle.
To test the two cleaners I obtained from a friend a couple grungy
CL engines that had probably never been cleaned. They had been put
away dirty and sludgy and left like that for more than 35 years.
At first I planned to use DC on one engine and PD on the other, but
then I realized I could make a better comparison by applying one
cleaner to one side of each engine and the other to the other side.
That’s what I did.
DC has a mayonnaiselike consistency and comes with a small, stiffbristled
brush for application. PD is less viscous; its spray penetrates
well between cylinder fins, yet it is enough like a gel to be
nondripping.
Both products come with strict cautionary warnings, which I
obeyed exactly. Wear rubber gloves (these products are strong skin
irritants) and safety glasses (you don’t want even a tiny droplet of
either to touch your eyes).
I did my engine-cleaning work outside. DC recommends it
although its vapors are far less pungent than those of the original
formula. PD can be used safely indoors and has a mild, pleasant aroma.
I laid both engines on their sides on a strip of aluminum foil and
thoroughly brushed DC onto one side, including half the head fins.
Two new engine cleaners are thoroughly tested
Also included in this column:
• The new O.S. LA Series engines
The Engine Shop Joe Wagner | [email protected]
Dawn Power Dissolver quickly removed the burned-on oil residue
from this RCV91-CD’s muffler and made it sparkle like new.
These grungy CL engines (from an anonymous donor) made fine
test subjects for two new model-engine cleaners.
The cleaners and their results. Aside from a few oxidation spots,
the engines look nearly new. No disassembly was needed!
Then I turned the test engines over onto their other sides and sprayed
PD on them. After roughly an hour (wearing rubber gloves and safety
glasses again) I used warm water and a stiff-bristled toothbrush to rinse
the engines clean over the kitchen sink.
I learned that DC seemed to be slightly more “aggressive” than PD,
but both cleaners worked exceedingly well. They removed all the
surface sludge with one application. Deeper incrustations, such as
between the head fins and in the cavity around the plug, needed a
second application.
One of the engines had a thick streak of orange paint (enamel, I
think) on its case. All of that came off completely after the second
cleaner-brush-rinse cycle.
Stan Grett had said that PD did a great job on four-stroke mufflers.
The one on my RCV91-CD had some burned-on oil residue, and it
wiped right off after I sprayed it with PD and let it sit an hour. I didn’t
even bother to remove the muffler from its engine; the PD’s sprayer
head projects a narrow, easily aimed stream. In fact, I didn’t do any
disassembly for any of these tests.
100 MODEL AVIATION
12sig4.QXD 10/25/06 11:24 AM Page 100O.S.’s new LA Series RC engines perform as great as they look. They are especially
made for sport fliers and beginners in power modeling.
This O.S. .25 LA-S CL engine started on its second flip and needed only 10 minutes of
break-in time. Notice the homemade needle-adjustment extension.
“What about the water getting inside?”
you may wonder. Not to worry. Some years
ago, when testing for corrosive effects of
water in fuel, I couldn’t generate a speck of
rust in any of six ball-bearing (Fox) engines,
even after spraying water directly on the
bearings. That’s because tap water is pH
neutral, I think.
After rinsing all the cleaners from my two
test engines I used my air compressor to blow
out the water that got inside. Then a few
blasts of WD-40 followed by After Run Oil
relubed the now-clean test engines.
Neither new engine-cleaning product is
quite perfect. Both will remove paint from
parts such as older K&B green heads and
mess up color anodizing. And neither can
clean off surface corrosion, such as rust on
steel and oxidation on aluminum, or wood
chips embedded in the propeller-driver
serrations. (You’ll need a wire brush and/or
steel wool to solve those problems.)
Other than that, DC and PD worked
amazingly well for me, as you can see from
the pictures. (The “after” photo shows my
two test engines as they emerged from
cleaning and rinse-off. No “touch-ups” with
steel wool or anything else have been done
yet.)
The new O.S. LA Series of engines is
instantly recognizable by its “midnight blue”
exterior finish. Made with O.S.’s usual
extreme precision and meticulous attention to
detail, these power plants are available in RC
and CL (called LA-S) versions and in a wide
range of sizes, from .10 through .65. All are
reasonably priced.
I obtained two of the smallest LA
engines—the .10 and .15—and a .25 LA-S.
The well-illustrated instruction booklets that
accompanied these power plants state that
they were “developed to meet the
requirements of beginners and sport flyers.”
The O.S. LA Series seems ideal for that
purpose.
For one thing, the manuals cover almost
everything a beginner would need to know.
They list all the accessories required, even
down to the fuel can and battery leads! They
describe and illustrate glow plug, propeller,
and muffler installation, and even how to fill
the fuel tank. Needle-valve adjustment is
thoroughly explained—and an entire page is
used to do so.
Troubleshooting is covered in detail, on
two full pages. There’s also a “flowchart”
diagram that covers every stage of adjusting
the carburetor. Exploded drawings are
provided that show every component of the
engines, along with their part numbers.
These things may be elementary to you
and me, but not to a beginner! In helping
many youngsters—and sometimes their
parents—get started in model aviation I’ve
found that no detail is so small that it can’t be
done incorrectly by someone who is
unfamiliar with model engines.
The only problem remaining is to get the
new engine owner to read and follow the
instructions. I’ve been messing with model
engines for several decades. Long ago I
learned that it’s always best to read the
instructions, all the way through, first. They
may not tell me anything I didn’t already
know, but there’s always the possibility that
they might.
The LA engines use simple, adjustable airbleed
carburetors that permit the needle valve
to be moved to the rear. It can be safely
adjusted there, two inches or more away from
the propeller.
(A minor but thoughtful feature of O.S.’s
needles is the provision for adding a wire
extension. There’s a precision hole in the outer
end of the needle for that purpose and a
setscrew for gripping the wire.)
Other small but important details that
impressed me in the LA-series engines are the
hardened steel washers between the propeller
driver and the case front and the positive-drive
design of the propeller driver itself.
(The washer prevents possible galling and
wear between the driver and case from
rearward pressure during electric starting. The
positive drive eliminates any chance of
slippage between the crankshaft and the
driver.)
When I first turned them over, the three
LAs felt smooth and snappy right out of the
box. Their instruction booklets confirmed my
feeling that very little break-in would be
required. The booklets also instruct how to go
about doing that in your airplane: just run out
one full tank of fuel on the ground, with the
needle set roughly half a turn rich.
After that you can fly—with a somewhat
rich needle setting that you decrease a trifle
after each flight. By the sixth time up, your LA
will be broken in nicely.
O.S. offers some useful accessories for the
LA engines, such as spinner nuts for easy
electric starting. Beginners are likely to
appreciate O.S.’s predrilled and pretapped
Radial Motor Mounts. Made from aluminum,
they will help cool their engines.
These mounts do cost more than the
molded plastic type. However, they eliminate
the need for close-tolerance drilling and
tapping work that the plastic units require. The
O.S. mounts come ready to use, complete with
the proper-size mounting screws. And unlike
many molded radial mounts, their mounting
surfaces are flat and parallel. MA
December 2006 101
12sig4.QXD 10/25/06 11:30 AM Page 101
