Introducing the Renewed Pre-Chamber Spark Plug: Part No. 7664653 (76.64.653)

Guascor 7664604 / Siemens 7664653 ( old 7664765) and replacement pre-chamber for HGM560 and SFGM560 engines / GP2 & GP1

Guascor spark plug / Siemens spark plug

In response to the continuous evolution of engine technology and the growing demand for higher performance and durability, we are proud to announce the release of the newly upgraded pre-chamber spark plug, now available under part number 7664653 (76.64.653).

🔧 A Technological Leap Forward

Previously known by part numbers Guascor 7664604 and Siemens 7664653, these spark plugs have undergone a significant transformation. The latest version reflects advancements in materials science, combustion efficiency, and thermal resilience—making it a superior choice for modern gas engines.

Key improvements include:

• Enhanced ignition performance for lean-burn and high-efficiency engines
• Improved thermal conductivity for better heat dissipation
• Extended service life under demanding operating conditions
• Robust design that withstands higher pressures and temperatures

⚙️ Reliability That Justifies the Investment

While the updated spark plug may come at a price point that exceeds initial market expectations, its exceptional reliability and extended lifecycle offer substantial long-term value. Engine operators and maintenance teams will benefit from:

• Reduced downtime due to fewer replacements
• Lower maintenance costs over time
• Consistent engine performance across a broader operating range

This makes the 7664653 spark plug not just a replacement—but an upgrade.

📦 Availability and Support

The new pre-chamber spark plug is now available for order and integration into compatible engine systems. 

Pre-chamber spark plugs offer faster, more stable combustion and improved fuel efficiency, especially under lean-burn conditions, compared to traditional spark plugs.

Here’s a breakdown of the key advantages:

🔥 Benefits of Pre-Chamber Spark Plugs

• Faster and more complete combustion: Pre-chamber spark plugs ignite a small, rich air-fuel mixture in a separate chamber. This produces high-energy jets that ignite the main chamber more rapidly and uniformly than a single-point spark.
• Improved knock resistance: The distributed ignition helps reduce the likelihood of engine knock, allowing for higher compression ratios and more aggressive tuning.
• Better fuel efficiency: These plugs support leaner combustion, which reduces fuel consumption and lowers CO₂ emissions, especially at part-load conditions.
• Enhanced combustion stability: The multiple ignition points from the pre-chamber jets stabilize combustion, particularly under high EGR (exhaust gas recirculation) or low-load scenarios.
• Higher ignition energy: They can ignite mixtures under higher intake pressures, making them suitable for turbocharged or downsized engines

High-Quality Spark Plug Alternatives for Budget-Conscious Operations

Not every engine operator has the flexibility to invest in premium components, especially when managing tight budgets or cost-sensitive projects. If you're unable to afford genuine pre-chamber spark plugs, rest assured—high-quality alternatives are available and can deliver reliable performance without compromising safety or efficiency.

💡 Smart Choices for Smart Budgets

Whether you're running a fleet of generators, maintaining industrial gas engines, or simply trying to stretch every penny, alternative spark plugs offer a practical solution. These substitutes are designed to meet essential performance standards and are often manufactured by reputable suppliers who understand the demands of modern combustion systems.

Benefits of choosing high-quality alternatives:

• Cost-effective operation without sacrificing core functionality
• Reliable ignition performance for standard engine loads
• Compatibility with a wide range of engine models
• Short-term savings that help balance maintenance budgets

🔍 What to Look For in an Alternative

When selecting a non-genuine spark plug, it's important to prioritize:

• Material quality: Look for nickel or platinum-tipped electrodes
• Thermal range: Ensure it matches your engine’s operating temperature
• Manufacturer reputation: Choose brands with proven track records
• Warranty or support: A good supplier stands behind their product

While these alternatives may not match the longevity or advanced engineering of genuine parts like the new 7664653 model, they can still serve as dependable options for less demanding applications or interim use.

🛠️ We're Here to Help

If you're unsure which alternative is right for your engine, our team can guide you through the selection process. We offer a curated range of spark plugs that balance affordability with performance—so you can keep your operations running smoothly without breaking the bank.

76.64.604 prechamber spark plugs available for Guascor HGM560 and SFGM560 gas engines. The new part number from 2019 was 7664765 (76.64.765) and traded under Siemens brand name however Siemens recently also changed the part number to 7664653 (76.64.653).

This 7664GPH / 7664GP2 & 7664GP1 pre-chamber spark plug is specially designed for the Guascor HGM560 engines, but also can be used in the Guascor SFGM series. The unique design of this pre-chamber gives a better engine performance.  Other advantages of this exclusive spark plug are reduced (NOx) emissions, less blockage of the holes and longer plug life time which reduces maintenance and costs.

These plugs were specially designed for Guascor HGM560 engines and can also be used in the Guascor SFGM series. The only requirement is the correct sleeve.

Seamless Integration: Implementing the 71.018-02 Pre-Chamber Spark Plug

As engine technology continues to evolve, so do the components that power high-performance systems. One such advancement is the alternative pre-chamber spark plug, engineered for optimal compatibility and ease of installation across several Guascor and Siemens engine platforms.

Replacement available for Guascor 7664604, Siemens 7664653, Siemens 7664685, Siemens 7664765

🔧 Designed for Precision Compatibility

This unique spark plug has been specially designed for use in the following engine models:

• Guascor Energy HGM560
• Siemens SGE-56HM

Its design ensures plug-and-play installation—meaning there is no need to adjust ignition timing, engine mapping, or other settings. This dramatically simplifies the replacement process and reduces the risk of configuration errors.

🔄 Extended Compatibility with SFGM Series

In addition to its primary applications, the 71.018-02 spark plug is also compatible with the Guascor® SFGM series. The only requirement for successful implementation in these engines is the use of the correct sleeve, which ensures proper fit and thermal contact.

✅ Key Benefits

• No tuning required: Maintains factory settings for ignition and performance
• Multi-engine compatibility: Covers both HGM560/SGE-56HM and SFGM series
• Simplified maintenance: Reduces installation time and technical complexity
• Reliable performance: Engineered for consistent combustion and durability

🛠️ Installation Notes

To implement the replacement:

1. Confirm engine model compatibility (HGM560, SGE-56HM, or SFGM series).
2. Ensure the correct sleeve is available for SFGM applications.
3. Remove the existing spark plug and install the 71.018-02 unit.
4. No timing or software adjustments are necessary.

This straightforward process allows operators to upgrade their ignition system with minimal downtime and maximum confidence.

Unique technology based on producer's own patents

- Better engine performance thanks to a very efficient pre-chamber design
- Longer plug lifetime, reduces maintenance
- Lower gas consumption achievable
- Competitive pricing

Spark plug user guideline

for GP2 & GP1 spark plugs (Guascor 7664604 / Siemens 7664653, 7664765)

Proper spark plug installation is very important to ensure optimal performance and safety on the engine. Please read these instructions carefully and always follow the instructions:

1./ Safety

Modem engine developments have led to more extreme engine running conditions, expressed in higher combustion pressures and temperatures. As a result of that, the latest ignition systems can provide higher ignition voltages and longer spark duration. This higher concentration of energy makes that nowadays a spark plug has to endure more severe conditions than ever before. Therefore, it is of the utmost importance to follow the guidelines below and the instructions that are provided by the engine manufacturer applicable when working around industrial engines.

These instructions should always be followed:

1.1./ Stay away from the spark plugs on a running engine

1.2./ Use the correct spark plug installation/removal tools

1.3./ Never over torque a sparkplug -to prevent damaging its construction

1.4./ Never under torque a spark plug – to prevent the plug from loosening

1.5./ Always use new spark plug gaskets to secure proper locking and sealing of the plug

1.6./ Never install spark plugs that have been dropped

1.7./ Keep spark plugs clean from grease or other contaminants during installation.

The installed spark plug type should be correctly chosen for the engine by either the engine- or spark plug manufacturer. Do not install different spark plugs if you are not certain that the plug is suitable for your engine application. Regularly check the physical con­dition of a spark plug to prevent premature failure.

2./ Installing spark plugs

Torque is one of the most critical aspects of spark plug installation. Torque directly affects the spark plugs' ability to transfer heat out of the combustion chamber.

A spark plug that is under-torqued will not be fully seated in the cylinder head; hence the heat transfer will be reduced. This will tend to elevate spark plug temperatures to unsafe levels, and pre-ignition and detonation will usually follow. Serious engine dama­ge is not far behind.

An over-torqued spark plug can suffer from severe stress to the metal shell which in turn can distort the spark plug's inner gas seals or even cause a hair­line fracture to the spark insulator, in either case, heat transfer can again be compromised and the above mentioned conditions can occur.

The cylinder head spark plug holes must always be cleaned and the good condition of the threads should be checked prior to installation, otherwise you may torqueing against dirt, debris or defective threads and the spark plug may actually end up under-torqued or improperly installed, even though your torque wrench says otherwise. Of course, you should only install spark plugs in a cool engine, because metal expands when it is hot, and installation may prove difficult. Proper torque specs for both aluminum and cast-iron cylinder heads are listed below.

Lubrication/ grease: Using grease is not recommended. However, if some anti-seize lubricant is used on the treads, then a small amount (pea size) should be spread uniformly on the clean threads and the specified installation torque should be reduced by approximately 10%. Also, if some dielectric grease is used on the ceramic insulator, then a small amount (pea size) should be spread uniformly after wiping clean the ceramic insulator with rubbing alcohol and a lint free cloth.

3./ (Re)gapping

Passive pre-chamber spark plugs (PPC) cannot be regapped. If PPC plug stops performing it will need to be removed, using the correct removal tool and exchanged for a new plug.

4./ Tools and Maintenance

When re-installing a spark plug, always:

4.1./ Use a new spark plug gasket (see table).

4.2./ Remove dirt and debris from the threads and clean them dry.

4.3./ Remove dirt and debris from the ceramic insulator and wipe it dry

4.4./ In the case of PPC, check that the pre-chamber holes are free of dirt and debris. The cleaning of the pre-chamber holes should be such to prevent pushing any dirt or debris inside the pre-chamber (e.g. always hold the PPC vertically with the pre-chamber holes facing down)

5./ Warranty

Tue spark plug is warranted to be free of defects in manufacturing or materials as sold. It does not carry a service time warranty due to the uncertain nature of the application in which they are placed, and their normal operating service life may vary considerably per application. Damage due to non-conformance to the user guideline, physical abuse, exposu­re to excessive temperature or moisture conditions or misapplication is not covered by this warranty.

6./ Disclaimer

The spark plug manufacturer / supplier does not accept any responsibility for consequential damages from falling plugs in the engine, as a result of:

6.1./ Incorrect handling or improper installation of the spark plugs

6.2./ Uncontrolled (ignition / combustion) behavior of the engine

6.3./ Spark plug wear

6.4./ Any other impact including the quality of the product

Pre-chamber spark plug 71.018-02 to replace Guascor 76.64.604 / 7664604

Spark Plugs Replacement Guide

In case the engine is operating at variable speed always select your spark plugs in reference with the highest speed range.

(*) In case the variation of the LHV of the utilized biogas exeeds 10 per cent it is recommended to used 76.64.292 (S7664761) spark plugs.

(**) In case of very contaminated gas it is recommended to use 76.64.292 (S 76.64.761) spark plugs. 71.018-02

Verified 2025 November