Valach VM 120 B2-4T Instruction 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

©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

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.

©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

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.

©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

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!

©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

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 igni­tion 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.

©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

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Y-Silencer VM-120 rear exhaust #7273

Silencers

The version with the Y-intake and rear ex­haust 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 instal­lation of two front exhaust silencers #7270
with headers and stainless steel exhaust
tubes #3882 in the Zlin 143L from DELRO.

©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

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!