Home / Lister Petter Engine Data / Lister D Thread Size Guide

Lister D Thread Size Guide

Lister D thread size guide kindly provided by Simon Breeze. This is not a definitive guide and is only what Simon has worked out.

Generally the size of the thread on a Whitworth fastener is one size above that used across the flats.

E.G. ¼ spanner size = 5/16 BSW, 3/16 spanner size = ¼ BSW, 5/16 spanner size = 3/8 BSW, 3/8 spanner size = 7/16 BSW

The three types of threads referenced are Whitworth, BSP & BA.

BSF threads include;

Sprocket retaining nuts (2) 3/8 BSF

Carburettor mixture adjuster thread 5/16" BSF

Vertical governor adjuster rod 3/16" BSF

5/16" BSW threads include;

Hopper cover (6)

Inspection plate (4)

Oil filler and oil filler lid (2 + 1)

Fuel tank straps (4)

Crank shaft housing boss (5)

Governor end plate (3)

Governor oil filler drip feed (1)

Rocker shaft locating bolt(s) (1 or 2 depending on spec)

Magneto housing bracket (4)

Carburettor & exhaust mountings (4)

Magneto guard (2)

Speed controller anchor in head (1)

¼" BSW threads include;

Float bowel lock nut (1)

Carb air plate bolts (3)

Crankshaft cover plate (3)

Carb jet lock screw (1)

Timing cover/gears (8)

Oil splash guard (3) (1 set screw 2 bolts)

SR1 Magneto coil securing studs (2)

SR1 Magneto threads for front mounting plate (3)

Oil dipper (1)

SR1 Mag base plate to body screws (4)

3/8" BSW threads include:

Cylinder head blanks for TVO tank bracket, rad support bracket etc (2)

Aux drive pulley locking bolt square head (1)

SR1 and RS1 magneto mounting bolts (3)

Cam shaft lock nut (1)

Governor housing special locking bolt (1)

3/16" BSW threads include;

Early carb mixture screw stop screws (2)

Early type hopper breather cover (with spring and plain type) (3)

Brass speed adjuster screw/rod

7/16" BSW threads

Cylinder head studs/nuts (5)

¾" BSP threads include;

Early head water drain tap boss

Early exhaust flange/pipe

1” BSP threads include:

Later head water drain tap boss.

Later exhaust flange/pipe

¼” BSP threads include:

Governor lock nut and adjuster (1)

Oil drain plugs (2)

Oil filler on timing case (1)

Carb jet locating thread in body (1)

Water drain tap (1) Also can be 3/8 BSP

1/8” BSP threads include;

Carb air valve adjuster and lock nut

Early type crankcase hopper breather (same insert as the carb air valve)

Rocker shaft greaser (1)

2BA threads include;

Fuel tap lever thread (single conventional type which often snaps)

For RS1 Magneto

Points cover retaining clip (1)

Coil hold own clamps (4)

Top cover screws (2)

Front bearing plate screws (3)

Condensor retaining screw (1)

For SR1 Magneto

Rear cover retaining screws (3)

Rear bearing cover screws (3)

Front housing blanks (6)

5BA threads include;

RS1 points retaining screws (2)

RS1 points base plate lower retaining screw (1)