Lambretta Technical Section
Lambretta Cylinder Shim Base Gasket: When to Use It and Why It’s Essential
If you are a fan of Lambretta tuning, you will surely have heard of the basic cylinder shimming gasket. This seemingly simple component plays a key role in engine optimization, especially when working on the connecting rod, piston and timing. In this article, we explain when to use it, why it is necessary and which shims to choose based on your modifications.
When do you use the base gasket?
The aluminum base gasket is mainly used in two cases:
1. When fitting longer connecting rods
A typical case is the adoption of a 110 mm connecting rod in combination with a piston with a standard 39 mm compression. In this configuration, a 3 mm base gasket is essential to compensate for the extra length of the connecting rod.
This shimming helps maintain the correct height of the piston in the cylinder, avoiding interference and ensuring a smooth stroke. It also acts on the squish height, improving combustion efficiency and increasing the overall performance of the engine.
2. To change the engine phases
Shimming the cylinder at the base is also an effective strategy to modify the engine timing. By increasing the thickness of the gasket, the intake, transfer and exhaust diagrams are raised, making the engine “taller” and more responsive at high revs.
This adjustment is particularly useful for those looking for a fine tuning of the engine, adapting it to sporting or touring use, depending on driving preferences.
Quali guarnizioni scegliere?
Le guarnizioni di base in alluminio sono disponibili per tutte le configurazioni Lambretta:
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Per carter piccolo (125, 150, 175 cc): spessori da 1 mm, 2 mm e 3 mm
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Per carter grande (200 cc): spessori da 1 mm, 2 mm e 3 mm
La scelta dello spessore dipende dal tipo di biella, dal pistone usato e dagli obiettivi di elaborazione. Una corretta scelta permette di ottenere il giusto squish e fasatura, ottimizzando la resa del motore.
Conclusion
The cylinder shimming base gasket is an essential tool for those who want to customize their Lambretta in a professional way. Whether you simply want to compensate for a longer connecting rod or modify the timing to obtain superior performance, choosing the right gasket is the first step towards effective and long-lasting tuning.
For more technical information or to purchase the gasket suitable for your configuration, contact us at:
📧 info@scooterthefero.com
