Short Description

Valve Guide Knurling & Resizing Arbors – Professional Valve Guide Restoration Tools

Precision valve guide knurling arbors designed for restoration of worn valve guides in automotive, motorcycle, diesel and industrial engines.
The tool forms a controlled spiral knurl pattern inside the valve guide bore, displacing material inward to reduce valve stem clearance and restore guide geometry.

What it actually does:

This is not a cutting or expanding tool.
The arbor plastically deforms the internal surface of the valve guide, creating spiral oil-retaining grooves while restoring proper valve stem fit.

Restores worn valve guides without replacement
Improves oil retention characteristics
Reduces valve stem play
Extends cylinder head service life
Maintains valve alignment geometry

How knurling works:

The spiral-forming section displaces guide material inward instead of removing material.
The process creates controlled plastic deformation while forming precision oil-retaining grooves.

Final sizing must always be completed using a valve guide reamer.

Valve Guide Materials Comparison:

Material Code	Material	Knurling Behavior	Wear Resistance
G1	Pearlitic Cast Iron	Excellent stability	High
G2	Phosphorus Cast Iron	Best for knurling	Very high
B1	Phosphor Bronze CuSn	Higher deformation	Medium-high
CN	CuNi Alloy	Stable deformation	Very high
SM	Sintered Powder Metal	Limited suitability	High

Typical Knurling Efficiency:

Guide Material	Typical ID Reduction	Oil Retention	Spring-back
G1 / G2 Cast Iron	0.04–0.07 mm	Very good	Low
B1 Bronze	0.06–0.10 mm	Excellent	Medium
CN CuNi Alloy	0.04–0.08 mm	Very good	Low
SM Sintered	0.03–0.05 mm	Good	High

Valve Guide Knurling Arbors:

The values below represent typical recovery ranges for standard G1/G2 cast iron, B1 bronze and CN CuNi valve guides.
Actual deformation depends on guide material, hardness, wear condition and lubrication during knurling operation.

Arbor Size	Typical Worn Guide ID	Typical ID Reduction	Final Bore Before Reaming	Recommended Reamer
5.6 mm	5.52–5.56	0.03–0.05 mm	5.48–5.52	5.5* mm
6.1 mm	6.02–6.07	0.04–0.06 mm	5.97–6.01	6.0* mm
6.2 mm	6.12–6.17	0.04–0.06 mm	6.07–6.11	6.1* mm
6.3 mm	6.22–6.28	0.04–0.07 mm	6.16–6.21	6.2* mm
6.6 mm	6.52–6.58	0.04–0.07 mm	6.46–6.52	6.5* mm
6.7 mm	6.62–6.69	0.04–0.07 mm	6.56–6.63	6.6* mm
7.1 mm	7.02–7.09	0.05–0.07 mm	6.95–7.01	7.0* mm
7.2 mm	7.12–7.19	0.05–0.08 mm	7.04–7.11	7.1* mm
7.3 mm	7.22–7.30	0.05–0.08 mm	7.14–7.21	7.2* mm
7.4 mm	7.32–7.40	0.05–0.08 mm	7.24–7.31	7.3* mm
8.1 mm	8.02–8.10	0.05–0.08 mm	7.94–8.01	8.0* mm
8.2 mm	8.12–8.20	0.05–0.08 mm	8.04–8.11	8.1* mm
8.3 mm	8.22–8.31	0.05–0.09 mm	8.13–8.21	8.2* mm
8.4 mm	8.32–8.41	0.05–0.09 mm	8.23–8.31	8.3* mm
8.7 mm	8.62–8.72	0.05–0.09 mm	8.53–8.61	8.6* mm
8.8 mm	8.72–8.82	0.05–0.10 mm	8.62–8.71	8.7* mm
9.1 mm	9.02–9.12	0.06–0.09 mm	8.93–9.01	9.0* mm
9.2 mm	9.12–9.22	0.06–0.09 mm	9.03–9.11	9.1* mm
9.3 mm	9.22–9.33	0.06–0.10 mm	9.12–9.21	9.2* mm
11.1 mm	11.00–11.12	0.06–0.10 mm	10.90–11.00	11.0* mm
11.2 mm	11.10–11.22	0.06–0.10 mm	11.00–11.10	11.1* mm
11.3 mm	11.20–11.33	0.06–0.11 mm	11.09–11.20	11.2* mm
11.4 mm	11.30–11.43	0.06–0.11 mm	11.19–11.30	11.3* mm

*Final valve guide sizing to 0,01 mm must always be performed using the recommended valve guide reamer to restore proper concentricity and valve stem clearance.

Best Materials for Knurling Recovery:

G2 Phosphorus Cast Iron — best dimensional stability and oil retention
G1 Pearlitic Cast Iron — excellent deformation control
B1 Bronze CuSn — excellent lubrication properties
CN CuNi Alloy — very high wear resistance

Worst Materials for Knurling Recovery:

SM Sintered Powder Metal — porous structure may collapse during deformation
Highly hardened guides — increased cracking risk
Severely heat-damaged guides — unstable material structure
Severely worn guides — poor geometry recovery

Specification:

Tool type: Valve Guide Knurling & Resizing Arbor
Application: Valve guide restoration
Material: HCS (High Carbon Steel)
Hardness: HRC 62 ±1
Working profile: Spiral knurling section
Lead geometry: Precision tapered cone

Typical recovery range:

Light wear: 0.03–0.05 mm
Standard wear: 0.05–0.08 mm
Maximum recommended recovery: up to 0.10 mm depending on guide material

Advantages:

Cost-effective guide restoration
Preserves original cylinder head
Improves oil retention
Reduces valve stem clearance
Long tool life
Professional engine rebuilding solution

Recommended guide materials:

G1/G2 Cast Iron
B1 Bronze CuSn
CN CuNi Alloys

Not recommended for:

SM Sintered Powder Metal
Cracked valve guides
Excessively oversized guides
Severely heat-damaged guides

Typical valve stem clearance after reaming:

Stem Size	Recommended Clearance
5–6 mm	0.015–0.035 mm
7–8 mm	0.020–0.045 mm
9–11 mm	0.025–0.055 mm

Important:

After knurling, the valve guide must always be calibrated using the proper valve guide reamer to achieve correct geometry, concentricity and valve stem clearance.

valve guide dia	11
Material	HSS
Manufacturer	TOKAR
Country of Manufacture	Ukraine

11.3mm Valve Guide Knurling & Resizing arbors