ran excellent with no carburetor adjustments
size prop shaft requires a 10mm or 13/64 drill/bit or ream for
exhaust stack makes the cowling cutout large
Pro now offers the "worlds first engine kit". The
kit comes full of individually wrapped parts. Once assembled,
you will have a 40cc gas engine ready to tear up the sky.
The advantage of the "kit engine" concept is that
you are not paying for labor to assemble the engine, so you
get more engine for your money.
kit comes with all the parts that you need to assemble the
engine including some tools, sealant and anti-sieze! Assembling
the engine is a fun project that will give you a better understanding
to the internals of your model's engine.
40cc Bore x Stroke: 40mm x 31mm Dry Weight: 1300g (2.87 lbs.) Carburetor: Walbro butterfly type w/pump Max Output: 3.95HP @ 7200 rpm Ignition: 4.8v - 6v DC-CDI Fuel: 93 plus octane (see note in text for oil mix
ratio) Propeller: 18 X 10, 20 x 8, 20 x 10 (Two Blade Propeller)
or 10mm Drill Bit or reamer (for Hole in Propeller)
hand tools (wrenches, sockets, hammer, see text)
engine comes packaged in a nice box. Opening the box reveals
many individual packets. Most of the parts are individually
bagged and labeled with part numbers. In some cases the parts
are grouped and multiple parts are in one bag with multiple
part numbers. The kit comes with a metric hex key and a spark
plug socket. Jim at AGAPE Racing and Hobby also includes gasket
sealer for the engine case and anti-sieze for the spark plug.
The instructions come printed on large sheets of paper and
include text and pictures. The instructions do reference the
part numbers on the bag, so I found it helpful to spread all
the parts out on a big table. This allowed me to quickly grab
the part that I needed when building the engine.
first step is to clear your workbench and gather your tools!
The CRRC Pro 40cc engine is assembled with a minimum of tools.
You will need a 14mm and 17mm combination wrench and some
screwdrivers, a hammer, a vice, some cotton swabs and a cleaner
such as acetone or alcohol. A torque wrench is also recommended.
The manufacturer even includes a hex wrench and a spark plug
socket. AGAPE Hobbies also includes sealant gasket maker and
anti-sieze with the kit.
The process described below is not intended to replace the
manufacturers directions. Always follow the manufacturers
As a rule of thumb, all fasteners should have a locking
mechanism (lock washer or Loctite) because vibrations of
the engine will loosen fasteners (and probably ruin your
day of flying) without a locking mechanism.
first step is to assemble the crankshaft. Press the seal on
and be sure to pay attention to the orientation. The propeller
adapter presses onto the crankshaft and is held in place with
a retaining shaft. Don't forget the lock washer. The manufacturer
provides an extra jam nut so you can tighten the two nuts
together and use the torque wrench to correctly tighten the
threaded shaft onto the crankshaft.
rotating assembly goes together quickly. The instructions
tell you to lubricate the bearing prior to installing it.
The clips that hold the wrist pin in are easy to lose when
installing, so be careful! It's best to use a hammer with
plastic ends to avoid damaging the metal surfaces. Make sure
you get the orientation of the piston right, there is an arrow
on the top of the piston head. When installing the piston
rings make sure that the orientation is correct and the open
sides of the rings fit between the pin in the piston.
there! Time to install the rotating assembly into the cylinder
and install the bottom of the crankcase. Use the acetone or
alcohol to clean the surfaces that the sealant will touch
and make sure they are dry before applying the sealant. Torque
the bolts in the classic "X" pattern.
through some of the forums on RC Universe you will see a suggestion
to use Loctite 603 on the bearings. The Loctite 603 is sold
at auto part stores and will prevent the bearing from spinning
in the case. If you use Loctite 603, rough the surfaces of
the bearings with 200 grit sandpaper and clean them with brake
cleaner. Use the Loctite sparingly, a few drops will do the
job. I did not use the Loctite on this engine because it was
not provided in the kit and I wanted to see if spinning bearings
would be an issue. I have not had any issues so far in my
carburetor and velocity stack install with 2 screws after
you install the adapter tube. The picture shows what order
the gaskets go in. Next you can install the tube from the
carburetor to the crankcase.
anti-sieze is included for the spark plug threads. Don't get
any on the electrode and as a rule of thumb try and keep the
anti-sieze away from the last 1-2 threads. When installing
spark plug, remember that it is threaded into aluminum, so
don't overtorque it. I would recommend using the torque wrench
any time that you reinstall the spark plug. When installing
the crankshaft sensor the plastic plate can crack easy, so
be careful not to overtorque the screws.
up weight came in at 43.9 oz. for the engine, 2.9 for the
mount and 4.1 for the ignition module. I used a template to
drill the mounting holes. Be sure to account for any side
and down thrust that you may add, as that will change the
ultimate location of the spinner and propeller in relation
to your cowling.
you look at the picture of the electronic ignition module
you will notice some fuel tubing between the ignition lead
and the RPM sensor wire on the bottom of the module. I placed
some tubing over the nut that holds the ignition module to
the firewall to prevent chafing on either wire. You have to
pay extra attention to vibration with a gas engine. You will
also notice the throttle is nonconductive (plastic). This
is an essential for a gas engine. I also have the ignition
module battery as far forward as possible (minimum 6"
from the radio gear) to minimize any interference issues.
is a manufacturer of oils for many applications. They
are known for their high quality and excellent performance.
The oil that was evaluated for this review was the Saber
Synthetic 100:1 Two Stroke Oil. This product is designed
to run at leaner ratios (100 parts gas to 1 part oil
verses 50:1 or 25:1). This means less buildup and a
cleaner running engine.
oil that I used for the first few hours and the first
flight of this engine was Homelite brand at a 50:1 mix
ratio. This oil is a synthetic oil with fuel stabilizers
and is sold in the big box home improvement stores where
2 stroke equipment (trimmers and chainsaws) are. I ran
this blend with Exxon Brand 93 Octane gas at a 50:1
mix ratio. Follow the mix ratio that the oil recommends.
If you run the engine at 25:1 to 35:1 with synthetic
oil like the manufacturer recommends the engine will
spit large amounts of excess oil out of the exhaust
and the engine will be very hard to start.
is what Jim from AGAPE Racing and Hobby recommends:
is further recommended that you use a 100% synthetic
2-cycle oil, mixed in the correct proportion for
both break-in and on-going operation. Amsoil Saber
100:1, for air cooled engines, is an excellent oil
and is appropriate for most applications. It is
advisable to use a richer mix for break-in and then
the normal mix for on going operation. For example,
using Amsoil Saber, the break-in ratio should be
50-60:1. For normal operation a ratio of 80:1 should
work well. It is important to measure the oil carefully.
Under no circumstances should the engine be run
without the proper amount of 2-cycle oil in the
is a side by side test of the Homelite Brand oil and
the AMSOIL. Since the engine is still "breaking
in", I followed Jim's recommendation of 50-60:1.
These tests were conducted on the same day, same conditions
with the same base fuel to keep variables to a minimum.
Two fuel cans were used with Exxon 93 Octane Gas from
the same pump. This test was done at 68 F temperature,30.04
in Hg pressure with 18x6-10, 18x10 and 20x6-10 Zinger
Brand wood propellers. A digital pull-scale and a digital
tachometer was used to take the measurements. The idle
was adjusted on the first run and then was not moved
for the duration of the tests. The fuel tank was completely
emptied between tests.
Full Power Static RPM
was a bit skeptical that there would be and differences
in the data between the two oils. The results show that
the AMSOIL gave consistently better performance with
the 18x10 and 20x6-10 propellers and equal with the
18x6-10 propeller. When the engine is fully broken in
and a 80:1 mixture is used I would expect the differences
in the Homelite Brand and the Amsoil Brand to increase.
AMSOIL Saber 100:1 oil performed excellent during my
testing. This oil has excellent lubricity and cleanliness
properties to control friction and prevent wear, plug
fouling, ring sticking and exhaust port blocking.
Engine Break In
engines require a break in period to allows the internal engine
parts to wear in correctly. The break in procedure for this
engine is simple. The instructions tell you to run the engine
for 5 minutes at low throttle, then stop and check for loose
fasteners and components. Then to run the engine 4 times at
30 minutes each, allowing the engine to cool between each engine
run. The two-hour break in period will also allow you to become
familiar with the engine and see if there are any engine related
problems (chafing, radio interference, etc.). I completed the
break in at 50:1 oil/gas mix ratio with 93 octane gas. The engine
will continue to break in as you fly it. Be sure to treat the
engine carefully when flying by applying throttle gently and
limit acrobatic maneuvers. You will probably need to lean the
carburetor out after the first few flights. It is important
not to run it rich for two long or you will wash away the carbon
deposits that give the engine more power (buildup on the top
of the piston increases compression ratio).
CRRC Pro 40cc engine was tested on a Cermark 1/4 Scale Pitts
biplane. The all up weight came in at a bit over 12 lbs. Even
with the smallest propeller the thrust to weight ratio was
more than 1. Since the engine was still breaking in, I limited
the flights to mild aerobatics and general pattern work.
you can see on the video I am using a heavy arc welders glove
to start the engine. Starting the engine is not hard, but
you do need to exercise caution around the propeller. Choke
the carburetor and turn the ignition on. The choke is applied
by closing the throttle and pulling the choke lever on the
carburetor. Flip the propeller until the engine "pops".
Then move the throttle to un-click the choke and flip the
propeller until the engine starts. Above 70 degrees the engine
would often start in 1-2 flips. When it was colder (like in
the video) the engine would require 5-6 flips. If you don't
flip the propeller hard enough when starting, it may start
backwards. If that happens, shut the ignition off and restart
engine ran out of the box without any adjustments to the carburetor.
After the break in I did adjust the throttle stop slightly.
Depending on the propeller the engine will idle at 1700-2000
rpm. You can hear the engine start to "4-stroke"
during some of the fly by's on the video. This is a sign that
it is time to start leaning the carburetor out.
engine ran excellent in flight. If you are making the transition
to gas power from glow power, you will like the reliability
and ease of operation that the gas power gives you. There
is no need to adjust needle valves each time you go to the
field and the fuel is much more economical.
Click Below to View the Videos:
found the CRRC Pro 40 engine to be a great value and a reliable
engine. Assembling the engine was easy and gave me first hand
knowledge of the inner workings of this engine. I found this
to be a great first gas engine experience as the support that
I received from Jim at AGAPE Racing and Hobby was top notch.
Pro 40 cc Engine and AMSOIL:
Racing and Hobby, LLC
The comments, observations and conclusions made in this review are solely with respect to the particular item the editor reviewed and may not apply generally to similar products by the manufacturer. We cannot be responsible for any manufacturer defects in workmanship or other deficiencies in products like the one featured in the review.