HKS 21003-AT006 Bcd Piston Kit G16e Step3 87.5 Installation Guide

HKS 21003-AT006 Bcd Piston Kit G16e Step3 87.5

Product Information

Specifications

• Product Name: BCD PISTON KIT G16E STEP3 87.5
• Part Number: 21003-AT006
• Application: TOYOTA GR Yaris, GR Corolla
• Engine Compatibility: 4BA-GXPA16, 4BA-GZEA14H, G16E-GTS
• Year Compatibility: 2020.09. – 2023.01.

Product Usage Instructions

Installation:

1. Read the installation manual before use.
2. Installation must be carried out by a professional.
3. Keep the manual for reference after installation.

Important Notes:

• Ensure you have the necessary tools and equipment for the installation.
• Be familiar with automotive systems and basic service procedures.
• Do not attempt installation if you are unsure about the process.
• Refer to the factory repair manual for additional safety precautions.

Product Features:
The FORGED PISTON KIT STEP3 for G16E is designed for racing use to increase engine power. It is optimized for improved engine output in high-performance applications on closed race tracks. Note that increased power may affect water and oil temperatures as well as oil pressure, so monitor these factors to maintain engine performance.

Frequently Asked Questions (FAQ)

• Q: Can this piston kit be used on vehicles other than JDM models?
  A: This kit was designed for a JDM vehicle and has not been tested in other markets. Use on other vehicles may require additional parts.

• Q: What is the recommended maintenance after installing this piston kit?
  A: Monitor water and oil temperatures, as well as oil pressure, to ensure optimal engine performance.

• Q: Is it necessary to follow the installation manual?
  A: Yes, installation must be done by a professional installer following the provided manual.

Keep this manual after after installation.

4BA-GZEA14H     :2023.01. ~

REMARKS| ※ This kit was designed on a JDM vehicle and has not yet been tested in other markets.

●    In order to use this kit, the following parts are required:

Part Number 23004-AT003    Connecting Rod Set STEP3 for G16E

REVISION OF MANUAL

INTRODUCTION

• Thank you for purchasing the HKS FORGED PISTON KIT STEP3 for G16E
• Installation must be done by a professional installer.
• After installation, follow the instructions in this manual.
• Please read this manual before installation.

NOTICE

• This manual assumes that you have and know to use the tools and equipment necessary to safely perform service operations on your vehicle.
• This manual assumes that you are familiar with typical automotive systems and basic service and repair procedures.
• Do not attempt to carry out the operations shown in this manual unless these assumptions are correct.
• Always have access to a factory repair manual.
• To avoid injury, follow the safety precautions contained in the factory repair manual.

PRODUCT FEATURES

• This product was developed for racing use and can increase in power of the engine. This product was developed to improve engine output to a higher range, and for race use on a closed course, where this kit is highly effective. However, when the power is increased, generally, the water temperature and/or the oil temperature tend to increase, and the oil pressure runs lower. Check the conditions of these to maintain the engine performance.
• To use this product on public roads, follow the necessary procedures and regulations for modified vehicles.

ATTENTION

• This manual indicates items you need to pay attention to to install this product safely and lists precautions to avoid any possible damage and/or accidents.
• This product is an automobile part. Do not use for any other purposes.
• HKS will not be responsible for any damage caused by incorrect installation and/or use, or use after modification and/or dismantling of this product.
• This product was designed based on installation onto a specific factory vehicle.
• The specifications of this product are subject to change without notice.
• The instructions are subject to change without notice. Make sure to refer to the most recent instructions.

SAFETY PRECAUTIONS

WARNING

• To prevent explosions and/or fires, always:
  • Work on the vehicle in a well-ventilated area.
  • Handle any flammable objects with care.
• To prevent electrical damage/burns/fires, always:
  • Disconnect the negative terminal of the battery before beginning installation.
  • When disconnecting connectors, take extra care to avoid breaking the connectors.
• Before jacking up the vehicle, always use wheel blocks and position the jack correctly. Also, do not start working under the vehicle without using jack stands.
  • Positioning the jack incorrectly imbalances the vehicle and may damage the vehicle’s body.
  • Incorrect use of jack stands may result in the vehicle falling causing serious injury or possibly death.

CAUTION

• Do not misuse this product.
  • Misuse of this product may lead to engine damage.
  • Misuse of this product may lead to loss of its original function.
• Before installation, make sure the engine bay temperature has cooled to approximately 40℃ /104oF.
  • Failure to let the engine cool down properly can lead to severe burns.
• Insert clean rags into open piping to prevent contaminants from entering the pipes.
  • If neglected, contaminants in the piping can lead to engine damage.
• Make sure that all of the parts listed in the Parts List are included in the kit.
• Reference the factory service manual when removing factory parts.
• Be careful when handling this product; avoid dropping or subjecting it to excessive impacts.
• Failure to do so may result in product damage or improper installation.
• the proper tools when tightening nuts and bolts. If over-tightened, the bolts may become damaged.
• the removed factory parts in a safe place for ease of reinstallation at a later date (if necessary). It is recommended to mark the positions of the removed factory parts.
• refilling oil, make sure to use the appropriate type of oil.

PARTS LIST

SPECIFICATIONS

COMPRESSION RATIO
The compression ratio will be the following when this HKS Piston Kit is used with the factory cylinder head: (The combustion chamber capacity is 49.6cc.)

INSTALLATION

1. Removal of Factory Parts.
   Remove factory parts referring to the factory service manual.

2. Clearance Verification for Piston.
   This piston kit is designed based on the stock bore size. (Boring and honing are not required.)

3. Confirm the O.D. of the piston skirt on the back of the piston. The diameter is between 87.450 to 87.460 mm. The last 2 numbers of the 3 digits after the decimal point are shown on the back of the piston. (e.g.: If the O.D. is 87.455 mm, “55” is shown on the back of the piston.) (See the figure1)

  *  **WW:** Weight
  *  **CU:** Mfg. Model Mark
  *  **LOT:** Mfg. Lot Mark  

The O.D. of the piston skirt on the back of the piston is before coating.

2. Confirm the Piston Clearance from each I.D. of the Cylinder Bore and O.D. of the Piston Skirt.  

Piston Clearance = “I.D. of the Cylinder Bore”－“O.D. of the Piston Skirt”

This is the clearance value without coating.

3. Honing cylinder may be required to make each cylinder bore inside diameter become the piston clearance designated value.  

IMPORTANT NOTICE
The optimal performance cannot be guaranteed if the piston clearance is not within the designated value.

3. Chamfering Cylinder Bore Bottom Edge
   Even on the stock cylinder a burr may be remained on the cylinder bore bottom edge. If the burr is on this edge, file off the circumference of the cylinder bore bottom edge using #600 or equivalent sandpaper or leutor. (See the Figure 2.)
   IMPORTANT NOTICE
   

   •   * Do not chamfer off more than the volume above. Over-chamfering will cause a piston to move inside the cylinder.

   • Be careful not to scratch other parts.

4. Adjust Clearance of Piston Rings Opening****
   Designated Clearance (mm)| Compression Ring No.1| C1| 0.160~0.185
   ---|---|---|---
   Compression Ring No.2| C2| 0.760~0.810
   Oil Ring Expander|  | 0.100~0.350

The clearance of piston rings must be adjusted to be within the range shown above along with 87.500 mm cylinder bore. If the bore diameter is finished with the plus tolerance, the clearance value will be larger than the specified value. The following shows how to measure the clearance. Adjust the clearance if necessary.

1. Place the piston ring in the middle of the cylinder using a piston (See figure 3.) Measure the clearance of the ring opening with a thickness gauge. 
2. File off the opening edge with a file or an oil stone to make the clearance within the designated value and C1<C2.  

IMPORTANT NOTICE

  * Adjust the clearance of the top and the second rings to be C1<C2 to reduce the oil consumption. If the clearance is C1>C2, the oil consumption may be extremely high.
  * If the clearance of the piston ring’s opening is not correct, it may cause excessive blowby or overconsumption of oil. Be careful not to scratch other parts when adjusting the clearance.

5. Installing Piston Rings

6. Install piston rings onto pistons using a piston ring expander. (See the figure 4.)
   Make sure the seals on the top and second ring are facing toward the top of the piston. (See the figure 5.)
   Seal

7. T: Compression Ring No.1

8. 2T: Compression Ring No.2
   IMPORTANT NOTICE

    * Clean the groove on the piston before installing the piston ring.
    * Use a piston ring expander to install piston rings.
      * Do not widen the clearance by hand; it may cause the deformation of rings or a change of the ring’s tension.
    * The direction of the piston ring must be correct. If not, the optimal performance of the piston ring cannot be guaranteed.
2. Attach the oil ring expander by hand.  

Next, attach the lower side rail and upper side rail. Ensure the oil ring expander and the upper or lower side rail are not misaligned. (Fig. 6)

3. Adjust the position so that the piston rings mating ports do not overlap as shown in Fig 7. 
  1. 1: Compression Ring No.1
  2. 2: Compression Ring No.2
  3. 3: Oil ring Expander
  4. 4: Upper side rail
  5. 5: Lower side rail

6. Calculation of Oil Clearance of Connecting Rod Small End
7. Measure the I.D. of the conrod small end with an inside micrometer. (See the figure 8.)
   Designated Value (mm)| 24.005 ~ 24.010
   ---|---
8. Measure the O.D. of the piston pin with a micrometer. (See the figure 9.)
   Designated Value (mm)| 23.998 ~ 24.002
   ---|---

9. Calculate the oil clearance from the O.D. of the Piston Pin and the I.D. of the Conrod Small End.
   Oil Clearance = “I.D. of the Conrod Small End” － “O.D. of the Piston Pin”

   Oil Clearance (mm)| 0.003 ~ 0.012

CAUTION Oil clearance must be within the range of the designated value. If not, it may cause damage to the engine due to the lack of oil film.

7. Assembling Parts
8. The side with an indent on the piston is the front side. Place the side with the indent to the front side of the engine. (See the figure 10.)
9. Assemble pistons and the factory parts referring to the factory service manual.
   CATION

  * Make sure the direction of the piston is correct.
  * The product performance cannot be guaranteed if the pistons are installed in an opposite side due to the asymmetrically-shaped piston.
  * Assemble the piston so that the oil jet does not interfere with the oil jet avoidance on the back side of the piston.
  * Interference may damage the oil jet.

Confirmation after Installation

1. Check the following before starting the engine:
   • Make sure pipes and hoses are routed and connected correctly.
   • Make sure the hoses are not twisted or bent.
   • Make sure the negative cable terminal is securely attached to the battery.
   • Make sure the level gauge for the engine oil is between H (F) – L.
   • Make sure all bolts and nuts are tightened.
   • Make sure all installed components do not come in contact with other parts.
2. Start the engine and check the following:

• Do not raise the engine RPM when the engine reaches the normal operation temperature. (Let it idle.)
  • Make sure oil is not leaking.
  • Make sure air is not leaking.
  • Make sure fuel, traction oil, coolant, and air are not leaking after revving the engine 2-3 times while in neutral.
  • Make sure the installed parts are not hitting each other.
  • Make sure the level gauge for the engine oil is between H (F) – L.

MAINTENANCE
Proper maintenance of this product is necessary in order to maintain the safety, reliability, and function of this product.

• Maintenance is the responsibility of the driver/owner.
• If work needs to be performed outside the scope of this manual, consult a professional.
• In order to maintain the performance of the kit, routine filter replacement is necessary. Recommended replacement intervals: Every 3,000-5,000km/2,000-3,200 miles or every 3-6 months.
• When upgrading spark plugs, choose the appropriate heat range applicable to the engine. Consult a professional for more details.
• For optimal performance, it is recommended to replace the engine oil every 3,000km or every 6 months.

ATTENTION

• Idling must be done before driving the vehicle.
• Before the engine bay temperature warms up, rapid acceleration and/or revving the engine 2-3 times while in neutral must be avoided.
• Even after the engine bay temperature has warmed up, excessive revving should be avoided to protect the engine.

TROUBLESHOOTING

WARNING

• Do not start the engine when oil and/or water leakage is noticed.
• Stop driving if you experience an abnormal drop in oil pressure; oil may be leaking. Do not restart the engine if the oil is leaking.
  • Explain the source of the leak to a professional and have the repairs performed by a professional.
  • If oil leakage is serious, ask a professional how to temporarily repair it and conduct the repair by yourself to prevent further damage.
  • Always follow the instructions given by a professional. If neglected, oil leakage can lead to a vehicle fire.
• If the vehicle gets damaged, have the repairs performed by a professional.
• If you experience any abnormal noises, scents, or vibrations from the vehicle while driving, reference the factory service manual.

FOR SUBSEQUENT OWNERS

• If this product is re-sold, please give this Installation Manual to the new owner.
• Consult a professional when removing this product from the vehicle.

HKS Co., Ltd.
7181 Kitayama, Fujinomiya, Shizuoka 418-0192, Japan https://www.hks- power.co.jp/en/

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