TD22

Alterations incorporated :-

General Notes :

Technical Data Document

TD 22

Sheet 1 of 3 Issue No. 17 Date 15.Jul.03

Valve Guide Bore Finish and Concentricity

735473, 74P056, 77P129, 77P565, 77P628, 84P046, 84P451, 92P141, 96C063, 97D051

This Technical Data (TD) Document provides the detailed requirements for which there is insufficient space on the component drawing.

The requirements of an individual TD may be altered by the addition of a specific note on the drawing. In this case the additional note shall override the requirements stated in the TD.

Any changes to the structure or content of this TD must be actioned by means of a Design Change (DC), approved by the owner.

Owned by :

Design Process Manager

Department : Product Engineering

PURPOSE.

To define the concentricity tolerances for valve guide bore to valve seat diameters, surface finishes and other seat alignment tolerances. CONTENTS. 1. DEFINITIONS 2. CONCENTRICTY 3. OVALITY and TAPER 4. PARALLELISM 5. VALVE SEAT SUPPLEMENTARY REQUIREMENTS 6. VALVE GUIDE SURFACE TEXTURE

© Perkins Engines Company Limited 1965, 2003

Perkins Confidential : Green

@Perkins

Technical Data Document

TD 22

Sheet 2 of 3 Issue No. 17 Date 15.Jul.03

Valve Guide Bore Finish and Concentricity

1. DEFINITIONS. ‘MZ’ = ‘Minimum Zone’ which is the annular space between two coplanar circles

concentric with one another, having a radial separation equal to the specified tolerance value. 2. CONCENTRICTY.

Valve Seat. (See also Clause 5.3) 2.1

The concentricity of the valve seat and flare diameters (see fig. 1) to the valve guide

parent bore shall be 0,08mm T.I.R. maximum.

Note: The tolerances apply to both inserted and non-inserted seatings.

2.2 Recess Diameters. The concentricity of diameters ‘A’, ‘B’, ‘X’ and ‘Y’ (see figs. 1 & 2) to the valve guide

parent bore shall be within 0,3mm T.I.R. The inlet port chamber, when required to be machined, shall be concentric to the valve guide parent bore within 0,38mm T.I.R.

3. OVALITY and TAPER. (Separate Guide Piece only) Valve guide parent bore taper and ovality shall not exceed the value derived from taking

50% of the diametral tolerances specified for valve guide parent bore.

4. PARALLELISM. The valve insert seating face ‘Z’ (see fig. 2) shall be parallel to the cylinder head bottom

face within 0,05mm T.I.R. 5. VALVE SEAT SUPPLEMENTARY REQUIREMENTS. 5.1 Out-of-roundness. Out-of-roundness of the valve seat shall not exceed 0,008mm MZ. 5.2 Surface Texture. Further to the surface texture CLA (Ra) as indicated on the component drawing, the

valve seat shall be free from evidence of cutter chatter and exhibit no score marks.

5.3 Contour Rate-of-change. ‘Pocket’ type deviations are not permitted, therefore the concentricity errors shall

only occur as a gradual departure from the true form.

© Perkins Engines Company Limited 1965, 2003

Perkins Confidential : Green

@Perkins

Technical Data Document

TD 22

Sheet 3 of 3 Issue No. 17 Date 15.Jul.03

Valve Guide Bore Finish and Concentricity

5.4 Seat Face Check. Using a production depth gauge and marking compound for assessment, a full even

seat face shall occur.

5.5 Inconsistent Lustre. It may occur in some instances, despite all conditions of form and surface being

satisfied, that the seating may exhibit an inferior surface by evidence of an

‘inconsistent lustre’. This condition shall not be used to condemn components for rejection, since it will have no adverse effect on sealing efficiency.

6. VALVE GUIDE SURFACE TEXTURE. 6.1 Integral Guide. The bore ‘V’ (see fig. 1) shall be within the limits 0,5 µm and 2,5 µm Ra. 6.2 Separate Guide. The roughness of the valve guide bore ‘G’ (see fig. 2) shall not exceed 1,6 µm Ra

except in the length ‘L’ where up to 2,5 µm Ra is acceptable provided the rougher section does not extend more than 12,5mm and the total sum of rougher section does not exceed 25mm.

With Guide Insert Without Guide InsertBore ‘G’ Bore ‘V’ Valve Guide Parent Bore or Valve Bore7mm Valve Seat Bottom Face fl A fl X Fig. 1

Valve Flare fl B fl Y Fig. 2

Face ‘Z’ © Perkins Engines Company Limited 1965, 2003

Perkins Confidential : Green

7mm Inlet Port ChamberLength ‘L’