Serdi 3.5 Valve Guide and Seat Cutting Machine

The Serdi 3.5 is a precision-engineered valve guide and seat cutting machine, optimized for modern multi-valve automotive and motorcycle cylinder heads. It uses Serdi’s patented triple air-float centering system and an integrated spindle motor to automatically align and cut valve seats — even on heads with small or offset guides.

 

This machine is a great fit for performance shops, rebuild shops, and custom engine builders who work on a variety of cylinder heads — from standard passenger cars and motorcycles to some light-duty performance or custom builds. Its capability to handle smaller guide diameters and deliver consistent seat finishes makes it ideal for multi-valve heads or precision seat jobs.

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Key Features

  • Triple Air-Float Centering System — The patented “live pilot + air-cushion” system aligns the spindle to each valve guide independently, ensuring accurate concentricity and seat alignment even if guides are slightly off-center or angled.
  • Integrated High-Precision Spindle (1.5 kW) — Built-in motor spindle provides stable torque and smooth rotation, enabling precise seat cutting without chatter — suitable for standard seats and high-performance applications alike.
  • Valve Seat Capacity: Ø 16–70 mm (0.6″–2.75″) — Covers the range needed for most automotive and motorcycle heads, making the machine versatile for small-bore four-cylinders up to modest V-heads.
  • Fine Depth Control — 0.01 mm (0.0004″) Resolution — Allows for extremely precise seat depth and consistency across multiple seats within a head — critical for performance and reliability.
  • Adjustable Head/Table Clamping & Tilt Versatility — The machine includes clamping fixtures that can accommodate vertical or inclined valve-guide heads; many common heads load easily with supplied spacers or clamping bars.
  • Built for Multi-Valve & Performance Heads — Because of its centering precision and seat-size range, the 3.5 handles small and compact multi-valve heads well — a necessity for many modern engines.
SpecificationValue
ModelSerdi 3.5 Valve Seat & Guide Machine
Valve Seat Diameter Capacity16 – 70 mm (0.6″ – 2.75″)
Spindle Motor Power1.5 kW built-in motor
Spindle Speed Range100 – 1,200 rpm
Centering SystemTriple air-float centering (live-pilot alignment)
Depth Control Resolution0.01 mm (0.0004″)
Head Support CapacityAutomotive & motorcycle heads — accommodates typical head sizes
Clamping & Tilt AdjustmentSupports vertical and inclined valve guides with fixture set
Control MethodManual operation with digital depth/spindle readouts
Typical ApplicationsAutomotive & motorcycle heads; multi-valve performance heads; guide replacement & seat recut jobs

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01

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Built on Real Engine-Rebuilding Experience

Decades before today’s engine shops trusted our equipment, Tony was already deep in the craft — rebuilding motors, machining blocks, and pushing for better precision.

A local newspaper once featured him as a standout young machinist, noting his drive, attention to detail, and obsession with doing things the right way. That same passion would eventually shape our company’s values.

Today, that commitment lives on in every machine we sell, every customer we support, and every shop we help succeed.