Valach VM 120 B2-4T User manual

Toni Clark practical scale GmbH
Instructions

©2015 Toni Clark practical scale GmbH Zeiss-Str.10 D-32312 Lübbecke Tel. [phone] Fax. [phone] www.toni-clark.com
Instructions Valach VM 120 B2-4T
2
Last revision: November 13th, 2015
Content
3 Specications Valach VM 120 B2-4T
4 Engine application
4 Description of the engine
4 Fuel
5 Mounting of the intake RAM tube
5 Mounting the prop shaft
5 Installation
5 Fuel tank
6 The ignition
6 Exhaust header
7 Silencer
8 Crank case venting
9 Carburetor
11 Propeller
11 Tighten the prop screws the right way
11 Safety instructions, the right use of propellers
12 Starting the engine
12 Ignition safety shut o
13 Breaking-in the engine
13 Maintenance
14 Changing the spark plugs
14 Adjusting the valve gap
15 Lubrication
15 Repair
15 Scope of supply
16 Appendix Basics of petrol engines
16 Engine cooling
16 Example of installation, the VM 170 B2-4T in a EMW 3m Pitts
17 Installation of the fuel tank
18 Fuel tank connections
19 Fuel tubing
19 Installation of the ignition
21 Carburetor linkage
23 VM 120 B2-4T rear view, Scale 1:1

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Valach VM 120 B2-4T Instructions
3
Specications Valach VM 120 B2-4T
Design: Four-stroke at twin engine OHV, 2 valves per cylinder, petroil lubrication.
Capacity: 120ccm
Power: approx.10hp
Bore: 47mm
Stroke: 35mm
Width over valve cover: 310 mm
Length: 168mm (engine mount to front side of prop hub)
Prop screw divided circle: 34 mm
Prop screws: 6 pieces M5 Hex socket screw
Thread prop shaft: M10x1
Engine mount: with four M6 Hex socket screws.
Weight: 3800 g (including ignition and prop screws)
Idle RPM: 900 RPM
Maximum RPM: 6200RPM
Recommended RPM range: 4500 to 5000 RPM on the ground (!)
Fuel mixture: 1:30 (1:25 while breaking-in)
Gasoline: At least 95 octane, ideal BP/Aral Ultimate 102
Oil: Valvoline SynPower 2T
Breaking-in time: 3 hours, the rst 2 hours with 1:25 mixture
Needle setting:
Low speed needle (L): 1 3/4 turns factory setting for breaking-in
1 1/4 turns later with intake RAM tube (!)
High speed needle (H): 2 turns factory setting for breaking-in
1 1/2 turns later with intake RAM tube (!)
Ignition: Valach microprocessor ignition.
Voltage range: 4.8-9 Volt, ideal 7.4 V (2 Lipo cells)
Safety shut o: automaticly after 1 minute of the prop being stationary.
Spark plug: NGK CM-6
Spark plug gap: 0.4 mm
Valve gap: 0.1 mm
Maintenance intervall:
Checking the valve gap: All 4-5 hours, while breaking-in after 10, 20 and then 30 minutes.
Lubricating of rocker arm bearings and valve shafts: All 4-5 hours, while checking the
valve gap.

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Instructions Valach VM 120 B2-4T
4
Engine application
The VM 120 B2-4T is intended to be used in model airplanes. Other applications are
not permitted!
Description of the engine
The VM 120 B2-4T is a gasoline powered four-stroke at twin engine, working on the
OHV principle with two valves per cylinder and petroil lubrication. The processor
controlled ignition makes starting a childs play and provides smooth running in all
RPM ranges.
Fuel
For fuel, use unleaded petrol with a minimum of 95 octane mixed with a full synthetic
two stroke oil.
We use and recommend ARAL Ultimate 102. It contains no bio-ethanol, the shelf life
of the mixture is much longer, the odor is reduced, the burning more gentle.
Attention with E10 Fuel: The shelf life is much shorter. Mixed fuel has to be used within
30 days!
The rst two hours of the breaking-in time has do be done with a mixture with a ratio
of 1:25, this equates 4% oil in the gasoline. After that we recommend a mixture of
1:30. The whole breaking-in time is approx. three hours.
After many tests, the oil we recommend for the Valach Motors four
stroke engines is Valvoline SynPower® 2T.
The extremely high quality BelRay H1R, we use for our two-stroke
engines, is not ideal for petrol lubrication in four-stroke engines.
BelRay H1R burns o very well and deposit free, but it does not blow
down past the piston rings into the crankcase as well as Valvoline
SynPower® 2T. The design engineer does not recommend to use
Castrol oils, because they built up far too much carbon.
Do not use ready mixed synthetic odorless chain saw fuel. Use
the four-stroke version without oil and mix it with Valvoline Syn-
Power® 2T .
Breaking-in mixture:
5 Liter gasoline and 200 ml oil , this 5 Liter are enough for the breaking-in.
Mixture afterwards:
5 Liter gasoline and 170 ml oil, or per Liter gasoline 33 ml oil.

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Valach VM 120 B2-4T Instructions
5
Mounting the intake RAM tube
The loosely supplied intake RAM tube , has to be mounted to the engine in any
case! Without it, the engine runs too lean, even with wider opened jet needles!
The carburetor screws have the right length to attach the intake RAM tube. Without
the intake tube, the screws are too long and the carburetor sits to loose on the engine.
Mounting the prop shaft
The prop shaft is supplied loose with the engine, because of ease of transport. The prop
shaft has to be screwed into the hub with a medium strength threat locking adhesive
(Loctite 642). At rst screw all 6 prop screws fully into the hub. Then screw both prop
nuts onto the shaft and lock them against each other. Apply the threat locking on
the threat of the prop hub, screw it in the hub and tighten it with the help of the two
nuts. It is sucient to hold the hub with a strong hand while tighten the prop shaft.
Installation
Mount the engine with M6 screws with matching length directly onto the rewall.
Do not use the engine if any of the four screws is not in place. Check regularly, if all
screws are securely tightened. We recommend the use of lock washers DIN 127 or a
threadlocking with a medium strength (Loctite 642).
To move the engine forward if necessary, stand o`s are supplied with the engine.
Do not use longer standos, they are torsionally not sti enough and cause a lot of
vibration in many circumstances. If necessary built an engine dome.
Do not use rubber shocks! They are not needed with this engine and you save a lot of
trouble with unsuitable rubber motor mounts. Mounted rigid, the VM 120 B2-4T runs
much smoother than any two-stroke engine.
Fuel tank
The fuel consumption of the VM 120 B2-4T is very low, compared to two-stroke engines.
A 500 ml fuel tank is enough for 15 minutes of ying. We recommend the use of a felt
clunk lter! Secure the Tygon®F4040 fuel tubing on the connections with 0.5 - 1mm
copper wire – wind it two times around the tubing and twist it a few times.
The ignition
Mount the ignition Hall sensor with two M3 screws on the crankcase so that the sensor
reaches over the prop hub. Secure the screws with low strength threadlocking adhesive.
Connect the ignition with a battery with a voltage range from 4.8 V to max. 9 V and a
minimum capacity of 1500 mAh. The best choice are two LiPo cells (2s, 7.4V). In any
case, and this is important, just use a switch and no voltage controller!
Never switch the ignition on or connect the battery, when any of the spark plug
caps is not connected with the spark plug!

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Instructions Valach VM 120 B2-4T
6
Mount the ignition protected against vibration into your model. Do not wrap the
ignition cables with spiral tubing. This makes the cables heavier and as a result more
prone for vibration, especially where the spiral tubing ends at the spark plug connector.
The ignition states are indicated by a build-in acoustic siren.
After one minute without turning the engine, the ignition is deactivated. If you turn
the engine at a slow speed during this minute, no spark will be triggered and the igni-
tion indicates, when the sensor is activated by the magnet with a piep. A spark is only
triggered at starting speed to prevent the engine from unintendes running.
The active state of the ignition is indicated at regular intervals by two beeps with a
rising pitch. The inactive state ( after 1 minute without turning the propeller) is indicated
in the same way at regular intervals by two beeps with falling pitch.
Exhaust header
With four-stroke engines feasible header lengths have almost no eect on power, but
header length has a pronounced eect on the sound. When the engine is run without
a silencer, a longer header produces a “warmer”, more pleasing exhaust tone.
Silver solder 18mm stainless steel bends #7281 onto the supplied steel anges or to
our special oval anges #7336. Connect the silencer with our exible stainless steel
exhaust tube #3882 to the widened up end of the header. Silver solder the tube on
the header. On the end to the silencer it is sucient to „screw“ the tube clockwise
on the silencer, and x it by turn it counter clockwise. The diameter of the wrapped
tube widens or narrows while twisting it, so no clips are necessary. We can supply the
stainless steel bends.
Do not use Loctite! Attach the header with M4 Hex socket screws and spring washers
DIN 127A to the cylinder heads.

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Valach VM 120 B2-4T Instructions
7
Y-Silencer VM-120 rear exhaust #7273
Silencers
The version with the Y-intake and rear ex-
haust develops the most power. Because
of the optimized gas ow, the engine turns
about 400 RPM more compared to other
silencers.
The advantage of using only one silencer
is the phenomenally light weight, and the
engine is not much louder than with two
silencers.
When quietness has the highest priority
for your engine installation, we can supply
twin silencers with a rear exhaust (#7275),
as well as with a front exhaust (#7270).
The picture shows exemplarily the instal-
lation of two front exhaust silencers #7270
with headers and stainless steel exhaust
tubes #3882 in the Zlin 143L from DELRO.

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Instructions Valach VM 120 B2-4T
8
Crankcase venting
The tube on the crankcase venting is used to remove the surplus oil out of the engine.
Do not extend the tube or reduce the diameter.
Hint: I guide the rests of the oil into a plastic container, that is lled with absorbent cotton
wads (from the dentist). The oil is absorbed by the cotton and will not come out while
the wildest aerobatic maneuvers. I use an empty 100 ml bottle of our silver solder ux
H1. The cap has a double sided tank nipple and eight 3 mm venting holes in it.
Do not omit the venting holes, they are absolutely necessary! The small tube on the
nipple guides the oil in the middle of the cotton in the bottle. I attached the container
with Velcro into the model, so it can be easily removed for draining.
The bottle must be placed lower then the crankcase vent!

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Valach VM 120 B2-4T Instructions
9
Carburetor
The loosely supplied intake RAM tube , has to be mounted to the engine in any
case! Without it, the engine runs too lean, also with wider opened jet needles!
The correct tuning of the engine can only be achieved, with a mounted intake RAM
tube. The intake tube saves fuel and keeps the model under the cowling cleaner. It is
not attached on the delivered engine, only for transportation reasons.
A pre adjusted Walbro carburetor with two jet needles ( L: low speed needle and H:
high speed needle) is mounted on the engine. The low speed needle inuences the
throttle response from idle to about 40% of the maximum RPM.
The basic adjustment for the high speed needle is 2 turns open (screw the needles
carefully in and screw them out two turns) and 1 3/4 turns for the low speed needle.
The ne-tuning for best performance and throttle response is made after the engine
is mounted in the model.
On my engine, after breaking-in the high speed needle is 1 1/2 turns and the low speed
needle 1 1/4 turns open.
The diaphragm pump into the carburetor is supplied with the pulsing crankcase
pressure by a tube. Keep an eye on the condition of this tube, because it is essential
for the correct functioning of the engine. You can read detailed instruction under
“Maintenance”.
Hint: Adjust the response time of your throttle servo in your transmitter to 1 sec. from idle
to full throttle. Other than expected, the throttle response will be faster and of course
more reliable, especially from low idle. The response time from full throttle to idle can
be on full servo speed.
Low speed needle High speed needle
The intake RAM tube is
absolutely necessary!
Without it, the engine will
run too lean.
Idle block screw, remove
after test bench runs..
Tube for the pressure
supply of the pump into
the carburator.

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Instructions Valach VM 120 B2-4T
10
It is a good idea to make a throttle linkage like the one showed above. The throttle
valve will move slower on idle than on full throttle. As a result the engine will accelerate
faster and more reliable from low idle. The use of a throttle curve in your transmitter
will NOT have the same eect, because it has no inuence on the servo speed. For
example, if you move the throttle stick fast from idle to full throttle, the transmiter
will not follow the trottle curve, it will only transmit the command „full throttle“. The
throttle valve will open on the full servospeed. The servoarm should have a lenght of
about 14 mm to maintain the full servotrack.
To link the throttle valve drill a 2 mm hole into the existing arm and attach a ball joint.
Keep the throttle linkage as light as possible, a carbon rod is the best choice. By no
means remove the spring. The life-time of the throttle valve bearing of the carburet-
tor depends on this spring and a light linkage. In the appendix you can see several
pictures of my installation of the engine in my 3 meter EMW Pitts.
I actuate the choke with a servo too. This gives me the opportunity to shut o the
engine, without using an electronic switch.
Choke arm
Throttle arm
Fuel nipple
The intake RAM tube is
absolutely neccesary!
Without it, the engine will
run too lean.
Throttle valve completly closed
Full throttle

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Valach VM 120 B2-4T Instructions
11
Propeller
The best RPM range for the VM-120 is 4500 to 5000 RPM on the ground.
Suitable Fiala-2-blade Propellers are: Suitable Fiala-3-blade Propellers:
28x14“ 30x12“ 30x14“ 32x12“ 27x14” 28x12”
With the smooth power stroke of the VM-120, it usually is not required to use 3-blade
propellers. Their eciency is about 5 % less. You would experience a noticable reduc-
tion in performance, when using a 28x12“ 3-blade instead of the 30x12“ 2-blade prop.
Hint: Drill the mounting screws of the propeller from both sides. Start from the backside
and than go on on the front side. This will make your holes more precise.
Tighten the propeller screws the right way
Insert all six prop screws and tighten the screws diametrically opposed, until they have
the same torque.
The M10x1 Nuts are not intended to mount the propeller on the engine. They can
become loose, y around and cause serious injuries.
Safety instructions, the right use of propellers
Do not stay in front or to the side of the propeller longer than needed. Make absolutely
clear to spectators, that they have to stay behind the propeller area.
Check the propeller before every ight. Do not repair propellers or use damaged
propellers.
Check every (!) day, before the rst start, if the six M5 prop screws are tightened.
Check the length of the M5 prop screws, before you attach the propeller. On the
one hand, they have to be long enough to form a reliable screw joint, on the other
hand they do not have too be to long, to prevent them from bottom out in the blind
hole. Keep in mind, especially wood props shrink a little, every time you tighten
the prop screws. Even if you tighten them up several times, the screws have to be
short enough.
For a (hopefully) better understanding: The friction between prop hub an the backside
of the propeller holds the prop. The friction is achieved by the contact pressure of the
six screws. If the friction is not sucient the propeller can move a bit, as a result the six
screws are loaded in bending mode with every revolution. Although this movement
is very small at the beginning, the screw will not withstand this alternating stress. The
screws will “sheer”, as most modelers call it. The truth is, that these screws will break
because of fatigue in the same manner as a spoon, that is bent by the clever Uri Geller
a few times.

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Instructions Valach VM 120 B2-4T
12
Starting the engine
To start the engine, pull on some working gloves. Never start the engine alone! Ask a
reliable and strong person to hold your model. Do not trust mechanical anchorage in
the ground, on fences or something similar. Approx. 20 kp of thrust is an enormous
force!
The rst start of the day:
1. Close the Choke valve completely.
2. Open the throttle a bit more than required for normal idle.
3. Ask a reliable and strong person to hold your model.
4. Switch on the ignition
5. Flip the engine, without any extra sucking in! The engine will start, when the car-
buretor has sucked in enough gasoline with closed choke and will stop after a few
revolutions.
6. Flip the engine a second time with closed choke.
7. Open the choke.
8. Flip the engine, until the engine starts to run constantly.
9. Run the engine with increased idle for about 10 seconds.
10. Accelerate to 25% throttle, to warm the engine up for about 30 seconds until you
taxi to the runway.
If your engine had run during the last hour:
1. Close the choke valve completely
2. Open the throttle valve a bit more than required for normal idle.
3. Ask a reliable and strong person to hold your model.
4. Flip the engine once with the ignition switched o.
5. Open the choke valve.
6. Switch on the ignition.
7. Flip the engine, usually it will start immediately.
8. Warm up the engine as described above.
Ignition safety shut o
Due to a safety shut o feature, the ignition will automatically shut o after one min-
ute without turning the propeller. This safety feature can easily become a trap, if you
get disturbed by anyone, while starting your engine. If you go on after a minute and
forgot to switch the ignition o and on again, you will ood your engine more and
more with every ip...
Switch o your ignition with the battery switch, after every ight. A small current is still
owing, when the ignition is on stand by. This small current will discharge your bat-
tery. The ignition has to be switched o after every ight with the ignition switch!

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Valach VM 120 B2-4T Instructions
13
Breaking-in the engine
The engine is factory tested and pre adjusted. While breaking-in the engine the level
of wear is increased. While breaking-in use a mixture of 1:25.
We recommend for the rst 30 Minutes a maximum of 3000 RPM. Afterwards you can
increase up to 5.000 RPM for a few seconds. Change continuously the throttle setting
and keep an eye on the engine temperature the rst two hours. Change the mixture to
1:30 and load the engine normally. Usually the breaking-in procedure lasts three hours.
Maintenance
The construction of the engine is laid out for a minimum of maintenance eort. The
valve gap has only to be controlled after all two or three operating hours after break-
ing in.
Lubricate the rocker arm bearings and the valve shafts while you are at it.
While breaking in, the valve gap has to be checked at shorter intervals, check it after 10
minutes the rst time, than go on for about 20 minutes and check it again, after that,
check the valve gap every 30 minutes, until after about ve hours only minor changes
will occur. Afterwards it is enough to check it every four or ve hours.
The backside of the crankcase is connected to the carburetor with a tube. This tube
guides the alternating crankcase pressure to the diaphragm pump into the carbure-
tor to actuate it. If you deploy the engine for aerobatics, with long vertical climbs and
hover maneuver like me, then have a regular look (at least while breaking-in) on this
tube. Oil in this line damps the alternating pressure and reduces the pump capacity.
As a result the engine runs too lean and can stop. Do not worry too much about it,
this is just meant as a hint to be prepared!
The following points have to be kept in mind as well, to guarantee a long faultless life:
Condition of the ignition battery.
Contact gap of the spark plugs, it should be 0.4 mm.
Change the spark plugs, if the electrodes are burned away.
Hint: It is a good idea to change the sparkplugs (NGK CM-6) after breaking-in the engine.
The higher metal abrasion during breaking-in is likely to collect on the insulator of the
sparkplug, it will then short the HT to earth.
Clean your engine occasionally with „WD 40“, especially the valve train needs this.
Afterward lubricate it as described in the section “Lubrication” with chain lube or our
Würth „HHS 5000“.

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Instructions Valach VM 120 B2-4T
14
Changing the spark plugs
Never tighten the spark plugs on a hot engine! The tension caused by the dierent
cooling can damage the threat in the cylinder head.
Screw the spark plugs in by hand until the gasket makes contact with the cylinder
head, and tighten them with a wrench a 1/4 turn.
Adjusting the valve gap
On a cold engine the valve gap should be 0.1 mm. The adjustments are made with
the supplied feeler gauge, the WS 7 wrench and the WS 2 Hex key.
1. Remove both valve covers.
2. Turn the crankshaft (on the propeller)
until the valves on one cylinder overlap. This
means, that both valves are slightly open, i.e.
one valve begins to open, while the other
starts to close. In this position of the crank-
shaft, you can adjust the valve gap of the
opposite(!) cylinder.
3. First o all measure the gap with the feeler
gauge (0.1 mm). The gap is OK when the
gauge can easily (without strong resistance)
be pushed through the valve end and the
rocker arm. The gap is to big, if no friction can
be felt. If the gauge sits tight, and can only
be pushed with a lot of resistance, the gap is
too narrow.
4. Loosen the locking nut and place the
feeler gauge between valve end and rocker
arm.
5. Turn the adjusting screw with the Hex key
in small steps, until the gauge can be pushed
with a little resistance though the gap.
6. Tighten the locking nut and check the gap
again with the feeler gauge. It is possible, that
the gap changed after locking the nut.
This photo series shows the adjusting of
the valve gap with the help of the feeler
gauge.

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Valach VM 120 B2-4T Instructions
15
Lubrication
It makes sense to lubricate the engine when adjusting the valve gap. Use a O-Road
chain lube with a temperature range of at least 150°C. After many tests, we use the
Würth „HHS 5000“, it contains PTFE and has a temperature range up to 250°C.
The pictures show the lubricating points on the rocker arm bearings and the valve shafts.
Repair
If you have any trouble with your engine, feel free to contact us:
Toni Clark practical scale GmbH
Zeiss-Str. 10
D-32312 Lübbecke
Tel.0049(0) 57415035 Fax.40338 e-mail: [e-mail]
Scope of supply
Engine Feeler gauge 0,1 mm
Instructions Ignition
Prop screws 4 stand os
Prop shaft Spark plug wrench
Prop shaft mounting nuts WS 7 wrench
Prop washer WS 2 Hex key
2 exhaust anges 2 exhaust gaskets

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Instructions Valach VM 120 B2-4T
16
Appendix Basics of petrol engines
Engine cooling
To cool the engine, it is not necessary to cut big holes into the cowling, but you have to
ensure, that the air ows around the cylinders before it leaves the cowl. Do not forget: The
air nds the way with the least resistance, unfortunately this is mostly not the way through
the cooling ns. The best material to make baes from is balsa, it can be positioned close to
the engine, as it will grind in, it will not cause interference and it is not sensitive to vibrations.
Air, which ows in a distance of more than a few millimeters from the cooling ns has
no eect on the cooling of the engine! In other words: The worst cooling is achieved by
a cowling with a huge volume, a big intake and no attempt to force the air through the
cooling ns of your engine.
Example of installation, the VM 170 B2-4T in a EMW 3m Pitts
For ight tests, I installed one of the prototypes of the VM 170 B2-4T into a 3 meter Pitts
from Weiershäuer. The model has a take o weight of 22,5 kg, this is with gasoline (for about
20 minutes of aerobatics) and 750 ml Smoke oil. The performance of the VM 170 B2-4T is
convincing and permits vertical acceleration with ease.

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Valach VM 120 B2-4T Instructions
17
Installation of the fuel tank
It is better for the fuel tank to be built into the model at a level above that of the carburetor.
The carburetor has non-return valves tted, so that the fuel cannot run out through the
carburetor as long as the engine is not running. For starting, it is better when the fuel line
is full with fuel. With the engine running, it does not matter how long the fuel line is. You
can install the tank anywhere you please in the model, at the CG position for example. But
keep the fuel line as straight as you can. Avoid bends that will hold air bubbles.
It is impossible to prevent the fuel in the tank from foaming. This foaming means you must
use our special cotton felt clunk lter - omit this clunk lter and your engine will draw more
air than fuel. Model aircraft fuel lters are useless for petrol engines; the transparent auto-
motive paper element fuel lters are also useless. The former have too coarse a mesh, and
the latter have a large capacity, allowing air to accumulate and thereby causing the engine
to stop, due to the sudden ingestion of this accumulated air by the carburetor. The second
and very important reason for using our cotton felt lter is that in petrol there is always a
certain amount of suspended matter, that is almost impossible to see with the naked eye.
This dirt will easily pass through the model lter and build up in the carburetor, mainly in
the low speed fuel passages. When this happens, the only cure is a new carburetor.
Fitting a T-piece in the fuel line between the tank and carburetor for fueling will be an
obvious mistake to most folks, but we have seen this method of short-circuiting the felt
clunk lter in the tank, with the obvious results, more often than one would imagine.
Here you can see the cooling air
ducting into the giant Pitts cowling.
The baes consisting of 4 mm
balsa, glued in with thick cyano.
Then I coated them with a layer of
dope. Afterwards I painted them
grey with a two component paint.
The visible lower bae plays a
mayor roll in cooling the engine.
It prevents the air from “diving”
under the cylinders and owing the
shortest way to the outlet on the
bottom of the cowling.

©2015 Toni Clark practical scale GmbH Zeiss-Str.10 D-32312 Lübbecke Tel. [phone] Fax. [phone] www.toni-clark.com
Instructions Valach VM 120 B2-4T
18
Fuel tank connections
Make two air vents made with fuel tubing, tted to two single sided nipples in the tanks
topside, central at the rear end. These two air vent lines must be led forward over the tank
and then down into the fuselage oor at the cooling air outlet of the engine cowling. One
of these vent lines (does not matter which) is used to ll the tank.
These two lines are always shut o, with two 3.5 mm self tapping screws 15 mm long with
heads removed, while the model is ying or otherwise parked.
Because the threads are so coarse, enough air can enter the tank, but even during violent
stunting no fuel will be lost. The saving in fuel is considerable! This system is simple and
100% reliable, also during lling the tank, you will
not spill fuel over your model. The double sided
tank nipple from the clunk lter is best placed in
the middle of the tank cap.
Note: Because of the better visibility on the pictures I used the black tubing. In my models, the
lighter Tygon tubing is used. I use the heat resistent black tubing for the smoke nipple on the header.

©2015 Toni Clark practical scale GmbH Zeiss-Str.10 D-32312 Lübbecke Tel. [phone] Fax. [phone] www.toni-clark.com
Valach VM 120 B2-4T Instructions
19
Fuel tubing
Do not use transparent PVC-fuel tubing! This clear fuel tubing often ts neatly onto the
nipples and seals nicely for a short while, but after a fairly short period, this clear tubing
becomes hard and expands a little in the process, due to the action of the petrol. This tub-
ing then moves due to engine vibration, allowing air to enter the fuel line. It is impossible
to seal this PVC tube satisfactorily.
Our specially made, thick-wall Neoprene fuel tubing is fairly soft and can be sealed perfectly
at the nipples with 0.5 mm copper or brass wire, by being wound twice around the tubing
and twisted together. Do not be tempted to use nylon tie straps or small Jubilee clips to
seal the fuel lines, these straps and clips do not exert pressure right around the tubing, they
only serve to pull the tubing into an oval shape on a round nipple. The black fuel tube is
very tough and due to having a very thick wall, it is not easily kinked.
A very good alternative tube is the transparent yellow Tygon® F-4040 tubing. It is much
lighter and does not expand in contact with petrol, also you can see air bubbles in the fuel.
You must use more care in laying this Tygon tube in the model to ensure that there are no
sharp bends. This tube is not especially heat resistant, therefore it follows it must not make
contact with any hot engine parts.
Installation of the ignition
Please install all components of the ignition, including the ignition battery as far away from
the remote control components as possible.
Please install all cables with greatest care. Especially the high voltage ignition cables should
not rub anywhere. Only an undamaged insulation can restrain the high voltage of about
20.000 Volt. If the screening is damaged, because the cables rubbed on a cutout in the
cowling, the insulation of the cable will get damaged or at least weakened. The ignition
voltage will not discharge at the spark plug anymore, but rather will strike through the
screening at the weak point. The engine will misre and because of the (second) discharger
the radio gear will be interfered very serious!
Use only knife edge contact switches such as our switch order no. #2024. Toggle switches
with roller contacts are not suitable as these are intended for 240 V. Used on low voltage,
oxidation can occur, this increases the contact resistance and will lead to ignition failure.
Take care with plugging together the JR-plugs and sockets by noting that the colors should
line up on opposite sides. It is possible with a little extra eort to push these together with
reverse polarity. No damage will be done but the ignition will of course be dead. I tape
these plugs and sockets with insulation tape for additional safety.

©2015 Toni Clark practical scale GmbH Zeiss-Str.10 D-32312 Lübbecke Tel. [phone] Fax. [phone] www.toni-clark.com
Instructions Valach VM 120 B2-4T
20
The ignition cables are xed with 8mm silicon tubing and cable ties. I cut the silicon tubing
lengthwise, it prevents the ignition cables much better against wear, than spiral tubing.
The stainless steel silencers on the pictures are simple absorption silencer. A 20 mm tube goes
right through the 40mm casing pipe. It is sieved from all sides on the full length with 4 mm
holes. This damps the high frequencies, but lets enough from the warm sound go through.
The super sti engine mount is made from 10x0,3 mm stainless steel tubes. It weighs despite of
its size just 330 g.
The black pump, on the bottom of the rewall is an Emcotec smoke pump. It injects the oil over
3mm stainless steel tubes into both exhaust header.
The oil reservoir is mounted with Velcro and can easily be removed to drain it.
The microprocessor Ignition is protected with a tough case and the electronics inside
are encapsulated to protect against vibration. In spite of this it is not a good idea to
simply mount the ignition box onto the rewall with a couple of cable ties. I screw the
ignition on a sheet of plywood. Aditionally I protect it against vibrations with a piece
of rubber between the ignition and the plywood.