Mira VGX-21 User manual

Instruction manual
English (EN)
Precision valve seat
refacing device

18 July 2023/ v1.6 VGX-21 |Serial-No. 963 © (All rights reserved)
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Table of contents
Safety Regulations...................................................................................................................................2
Elementary safety-advices.......................................................................................................................3
Copyright ©...............................................................................................................................................7
Non-liability...............................................................................................................................................8
Warranty....................................................................................................................................................8
Declaration of conformity........................................................................................................................9
1 Device parts VGX-21........................................................................................................................11
1.1 Device parts AV-Mobile .................................................................................................................12
2 Installation of the cylinderhead support AV-Mobile......................................................................13
3 Clamping of the cylinderheads.......................................................................................................14
4 Processing of valve seats...............................................................................................................15
5 Processing of insert counterbores (ring seats).............................................................................24
5.1 Processing the Counterbores.........................................................................................................25
6 Changing tool-heads.......................................................................................................................26
7 Maintenance of the VGX-21.............................................................................................................27
7.1 Advancing device (Feed nut) .........................................................................................................27
7.2 Hydraulic oil clamping system........................................................................................................28
8 Spare parts list.................................................................................................................................29
9 Assembly drawing of the VGX-21 (with crank handle)..................................................................31
10 Schematic diagram..........................................................................................................................32
11 Special accessories ........................................................................................................................33

18 July 2023/ v1.6 VGX-21 |Serial-No. 963 © (All rights reserved)
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Safety Regulations
For the eletronic installation activity, please pay attention to the local directives.
We would like to draw your attention to some dangers, which may occur. You should therefore read the following instructions carefully
and proceed accordingly.
It is not allowed to use the device in a dusty, humid or explosive environment => Danger of shortcircuit!
The VGX-21 must not be used with a opened chassis!
To bypass or paste-over the handgrip-switch as well, can be very dangerous!
During processing the valve seats, there must be worn safety goggles! There must be worn a hairnet for long hair as well!
Risk of injury by the formtool of the rotating spindle!
Avoid to suck in any dirt or dust while the vacuum pump is running!
The filter and the suction cable should be controlled in constant intervalls!
Clean the suction cable if it is polluted and exchange the filter!
Before working on electronic elements and repairs, the device must be fully isolated from the current electric circuits!
Repairs are only allowed by the local MIRA-dealer or the manufacturer (MINELLI Corporation) in every case!
Only use genuine MIRA spare parts, which are registered in the respective instruction manual!
Do not touch the electric circuits of the device = Contact with these circuits are dangerous to life!
Modifying of the electronical elements could cause severe aftermath!
Repairs of the VGX-21 must be basically accomplished ONLY by authorised personnel or the MINELLI Corporation.
Safety advices for the VGX-21 valve seat refacing unit
The following safety advices must be observed in every phase of the launching, during processing valve seats and the maintenance or
repairs. Disregarding of these assignments is a incorrect use of the device.
Earthing of the device
To reach an optimum touch protection, the device must be earthed. Therefore the earth-clamp must be connected with the earthing
of the main circuit.
Do not use in explosive environment!
The use of the device in explosive environment (flammable gases, vapours or dust) may induce the lightning of these materials and are
strictly forbidden.
ATTENTION!
1. To avoid the risk of partial overheating, the device must not be used in dusty or steamy atmossphere.
2. The device must not be used in wet environment, respectively the device must not be exposured to rain or dew. This may induce an
electric connection between electonic elements in the devices.
3. The User of this device must accomplish access, launching, setting and service by authorised personnel. Operations by the
electronic elements of the device are dangerous because of the electric tension, that can be a high risk of an electric shock. The
electric tension can even exist for a short time if the device is already switched off. Before starting service-operations on the
device, make sure that the capacitors of the device do not carry electric tension.
4. The device builds no physical separation. It is prohibited to work on the connectors of the device if the electric tension is running.
Running of the device without mechanical switch or fuse in the power supply is forbidden.
5. Service and adjusting operations must always be done by a minimum of 2 people. In an emergency, there must be a person that
can cut off the electric circuit to execute first aid.
6. This device must not be used for emergency- and safety tests. A failure or damage of the connected VGX-21 by the running electric
tension can be induced.
7. Every contact with the electric circuits must be avoid. During the operation, every contact with these circuits are dangerous to life.
Therefore added, the device can be damaged by careless contact of sensitive elements.
8. To avoid further risks, you must gain the agreement of the manufacturer MINELLI Corporation, if you want to add, change, replace
and/or manipulate some parts of the device by yourself.
9. If there are some repairs or replacing works to do, the VGX-21 must always becompletely disconnectec from the electric circuits.
By Repairs and replacing works read carefully the certain chapters in the Instruction manual. (See “Maintenance of the VGX-
21“on Page 27)

18 July 2023/ v1.6 VGX-21 |Serial-No. 963 © (All rights reserved)
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Elementary safety-advices
Advices in the instruction manual
•The knowledge of the Basic safety advices and safety regulation are basic conditions for the
design to security using of this device in cooperation with the “Safety Regulations”on page 2.
•The instruction manual contains the core of the importants advices, to use this device in a safety
condition.
•The instruction manual, especially the safety advices, must be consider by all users, who work
with this device.
•Beyond that it must be paid attention to the valid location regulation and the provisions of the
accident control.
Responsibility of the operator
The operator are committed to let only user working, if they
•will be intimate to the basic advices for working safety and accident control. They must also be
instructed to the device application.
•have read, understood and signed the safety advices and warning notices in the instruction
manual.
The safety-conscious work from the users will be controlled in constand intevalls.
Responsibility of the employees
The employees who work on the device have to commit, before beginning the work:
•that they pay attention to the basic safety advices of work safety and accident control.
•that they have read, understood and signed the safety advices and warning notices in the
instruction manual.
Risk in using the device
The device VGX-21 has been developed based on the newest state of technology and was
constructed by the accepted safety-related regulation. However, it is possible by using the device,
that there appear some risks for the user or third persons, especially if the device is misused and
operated not accordingly to the MIRA operation manual. Only utilise the device:
•for designated use.
•in safety-related good condition.
Breakdowns are to correct immediately, if they become some vitiations to the safety-advices.
Conventional utilisation
The MIRA VGX-21 device is exclusively designed for refacing and cutting valve seats and insert-
counterbores of the cylinder heads for combustion engines. Another- or beyond going utilisation are
not intended. The Minelli Corporation will not be liable for damages which evolved herefrom. To the
intended utilisation also belongs:
•to pay attention of every advice from the instruction manual and
•to keep on the control- and service work.

18 July 2023/ v1.6 VGX-21 |Serial-No. 963 © (All rights reserved)
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Warranty and liability
Warranty matters are described in MIRA‘s terms of sales and return policy conditions and are a
integral part of any sales contract between MIRA an the customer. Warranty- and liability by people
and material assets are void, if they had one or more of the following causations:
➢Non-designated use of the device
➢Incorrect mounting, launching, using and servicing of the device
➢Operating of the device with damaged safety-apparates or incorrect and missing mounting of the
safety- and protection apparates
➢Non-observance of the advices in the instruction manual with regard to the transport, storage,
assembling, launching, operating and servicing of the device
➢Independent constructive manipulating of the device
➢Independent manipulation of the VGX-21 (for example: magnetic plate or switches, protection and
earthing against dangerous currents)
➢Bad monitoring of the device components, which are wearout
➢Incorrect executed repairs
➢Emergencies by external-material influence and force majeure
Symbol- and advice description
Following descriptions and icons will be used for risks in this instruction manual:
Warning notice –Generally danger: Shows a potentially dangerous situation, which can
induce low to severe injuries up to death, if they will be ignored.
Warning notice –Danger of an electric shock: Shows a dangerous situation, which can
induce an electric shock and severe burns up to death, if they will be ignored.
Warning notice –Danger of squeezing: Shows a potentially dangerous situation, which can
induce low to severe constant injuries, if they will be ignored.
Info –notice: Shows Information and/or additions, which are important for theappropriate use
of the machine and its functionality.
Application –notice: Shows accessories and further application features of the machine.
Organisational provisions
•The operator must prepare the required safety-equipment.
•All safety-devices must be checked by constant intervalls.
Protection-apparates
•Before launching the device, all protection-apparates must be correct installed and functioning.
•Protection-devices maybe only removed
- after shutdown and
- coverage against re-launching of the VGX-21
•By delivering of part-components, the protection-devices must be installed agreeable to the
regulation by the operator.

18 July 2023/ v1.6 VGX-21 |Serial-No. 963 © (All rights reserved)
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Informative safety provisions
•The instruction manual must be always kept by the location of the device.
•Additional to the instruction manual, there must be paid attention to the generally and local
regulation of the accident control and pollution control. They must be prepared.
•All safety- and warning advices on the device must be kept in a readable condition
Training of the users
•Only introduced and trained users may work on the device.
•The user competence must be clearly appointed for the mounting, launching, handling, servicing
and repairing of the device.
•Beginners may only work on the device under the attendance of an experienced user.
Device- and apparate electrics
•Do not manipulate the magnetic plate and do not modificate the switches in any circumstances.
•Only introduced users are be able, to apply the VGX-21 device.
Safety provisions in the standard mode
•All protection-apparates must be absolute functioning, if the device is in operation.
•Before switching-on the device, there must be paid attention that nobody is exposed to the risks
by starting the device.
•The device should be checked for external damages and safety device functioning in minimum
one time by every shift.
Risks by electrical energy
•The works on the electrical supply must be done by an expert (Certified Electrician, etc.)
•The electrical equipment of the device must be checked in constant intevalls. Lose connections
and damaged cables/wires must be removed immediately.
•If it is essential to do work on energised components, there must be a second person/user that
guards the work and can remove the power cord from the main socket in case of an emergency.
Especially danger areas
•The VGX-21 valve seat refacing unit contains rotating machine parts, which are an upper risk for
(long) hair, hands and fingers. Wear suitable safety equipment (e.g. hairnet etc.).
•The magnetic base of the VGX-21 may be a risk of squeezing fingers and hands by clamping
down the device on a handling plate. The device must be clamped carefully and thoughtful.
•The mounted formtools maybe have very sharply and spiky turnings, which can induces severe
lacerations or others injures. It must be worked careful and thoughtful by refacing and recutting
the valve seats!
Leaking of hazardous dust and vapours
•During the refacing of the valve seats, metal dust, particles and vapour from the cutting oil can
occur. They can irritate and injure the lungs and the eyes. Wear suitable safety equipment (e.g.
protection goggles, mask etc.). Ensure enough ventilation during processing valve seats. Special
safety precaution, for example: eyeflushing device.

18 July 2023/ v1.6 VGX-21 |Serial-No. 963 © (All rights reserved)
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Service and repairs, trouble shooting
•Arrange the prescribed setting-, servicing- and checking works to the limit date.
•The users must be informed about imminent servicing and repairs of the device.
•All of the device pre- or after switched machine parts and operating mediums, e.g. electricity,
must be ensured against accidentally launching.
•By all servicing-, checking- andrepairing works, the devicemust be switched off from main supply
and the mainswitch must be locked against unexpectet restarting
- Lock and strip of the key from the main switch, if it is possible.
- Add Add a shield or Information on to the device, which the device may not be able to be
switched on.
•Greater devices must be carefully mounted and ensured on lifting gears, by the replacing.
•Check loosened screw connections for a compact seat.
•After finishing the service work, the saftey apparates of the device must be checked and verified.
Constructive modifications on the device
•Without written authorisation by the manufacturer Minelli Corp. (MIRA), theres no right to add
some components and/or making some modifications on the device. This is also valid for welding
wearing components.
•All constructive modifications requires a written affirmation from the Minelli Corp. (MIRA)
•Faulty device parts must be replaced by original replacements only.
•Only use original genuine mira replacement parts.
- By replacements of externals, there are no guarantee, that they are constructed for the required
operational demands and the required safety functions.
Cleaning of the device and disposal of wastes
•Used stuff and materials must be correct removed and handled, especially:
- by works on greasing systems- and devices
- by cleaning with dissolvers
•The device must be cleaned external in constant intevalls, with a flannel and less of machine- or
industry cleaner.
•Further cleaning per grade of using and grade of pollution of the device.
•The packaging material of the VGX-21, after delivering, must be correct disposed in the respective
waste container and/or according to local envirement legislations!
Noise emission of the device
•The noise pressure level going out from the VGX-21, behave to 0dB(A)
•In combinated use with the Vario Drive System, there is a noise pressure level up to 70dB(A)
going out from the Vario Drive.
•Based on the local environment, there is a possibility of a higher noise pressure level. This can
cause noise deafness. In this case, the users must be wearing protection devices (e.g. hearing
protection, Oro-pax etc.)
Safety advices for carrying
•For transport, the VGX-21 must be carried in the storage box (in the same as it was delivered
from the Minelli Corporation).
•Ensure all moving parts from the device against loosening, by the transport.
•The device must be protected against damages by the transport. If essential, the device can be
fully packed in.
•The MINELLI Corporation will not take liability for ignoring and not paying attention of the safety
regulations by shipment.

18 July 2023/ v1.6 VGX-21 |Serial-No. 963 © (All rights reserved)
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Copyright ©
The exclusive copyright of this instruction manual remains in the hands of the MINELLI Corporation. (MIRA)
This instruction manual is appointed for the operator and his personal.
Minelli Corporation
MIRA Division
Mattenstrasse 3
CH-8330 Pfäffikon ZH
Switzerland CH
For the provided technical documentation see the assigned person at chapter “Declaration of conformity”
on page 9.

18 July 2023/ v1.6 VGX-21 |Serial-No. 963 © (All rights reserved)
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Non-liability
The valve seat refacing device VGX-21 may only be operated according to the Operating Instructions. The
manufacturer refuses to accept any liability for accidents and damages caused by incorrect operation. He
also refuses any liability for alienated use of the device.
Warranty
In case of manufacturing or material defects Minelli Corporation will replace the defective part or parts at no
charge within 12 months after the date of final purchase. No further claims can be covered under the
warranty. Defective parts must be returned along with proof of purchase. The warranty does not cover any
subsequent damage caused by these defective parts. The warranty does not cover unprofessional handling,
the use of incorrect electronic parts or deliberate damage, nor does it cover shipping and packing costs.

18 July 2023/ v1.6 VGX-21 |Serial-No. 963 © (All rights reserved)
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Declaration of conformity