Threads, Reconditioning

Repairs to internal threads in the cylinder block, intermediate section and cylinder head are carried out with the aid of thread inserts. Some threaded holes cannot be repaired in this way because the threads are too fine. (Holes which should not be repaired are also included in the tables below.)





THREAD INSERTS
Thread inserts are made of cold-rolled wire sectioned to ISO thread standards. The material used is stainless, acid-resistant steel. Inserts are designed to be fitted in holes which are drilled and threaded as per the standard thread insert tables.

Thread inserts have a handle with breaking instructions. This handle must be knocked off after installation.

PROCEDURE





1. Drill out the hole to be repaired
- Use a drill diameter and length taken from the thread insert tables found with steps 6, 7 and 8.
- Do not lower the edges of holes; we recommend only a slight angling.





2. Thread the hole using the die for the thread insert
- Use the right die for the material and work concerned
- When working on an 10 mm threaded hole, use a die for an 10 mm thread insert.
- Thread down to the right depth (see table).
- Blow hole clean.
- Use correct length thread insert (see table).





3. Insert thread insert in fitting tool Insert the insert with the handle downwards.





4. Install thread insert
- Hold fitting tool immediately over the threaded hole.
- Wind thread insert in until approximately one complete turn remains projected out of the hole.
- If a hole goes right through, the thread insert must not project out of the bottom of the hole.





5. Knock off fitting pin
- Knock handle off with pin hammer.
Do not use the fitting tool to knock the handle off.
- Remove handle and blow hole clean.
- Using a bolt, check that the thread is clear and that the thread insert is installed correctly.

Thread Repair Table - Cylinder Head And Camshaft Casing:

Rear View - Cylinder Head:

Front View - Cylinder Head:

LH View - Cylinder Head:

RH View - Cylinder Head:

Top View - Cylinder Head:

Top View - Camshaft Casing:

6. Repairs to cylinder head and camshaft casing
- The table shows which holes in the cylinder head and camshaft casing can be repaired and which thread inserts to use.
- The table also shows drilling depth and diameter and the part numbers for each thread insert.

Thread Repair Chart - Cylinder Block And Intermediate Section:

Underside View, Intermediate Section:

Underside View, Cylinder Block:

LH Side, Cylinder Block And Intermediate Section:

7. Repairs to cylinder block and intermediate section
- The table shows which threaded holes on the cylinder block (CB) and intermediate section (IS) can be repaired and which thread inserts to use.
- The table also shows drilling depth and drill diameter and the part numbers for the respective thread inserts.

NOTE: Do not repair holes marked V3 with thread inserts.

Thread Repair - Cylinder Block And Intermediate Section (Continued):

RH Side, Cylinder Block And Intermediate Section:

Top View, Cylinder Block:

Front View, Cylinder Block And Intermediate Section:

Rear View, Cylinder Block And Intermediate Section:

8. Further repairs, cylinder block and intermediate section (Continued)
- The table shows which threaded holes in the cylinder block (CB) and intermediate section (IS) can be repaired and which thread inserts to use. It also shows the drilling depth, drill diameter and part number for each thread insert.

NOTE: Holes marked H4, H5, BV3, BV5, BV10 and BV21 must not be repaired using thread inserts.