By Håvard
Bækkevold and Anders Kråbøl.
The head being prepared is a Mklll Zodiac head and is being fitted with Volvo B20 valves as they were the easiest available to Håvard in his country of Norway. The lead free inserts are cut 5mm deep into the head.
Here the
brutal work has been done - no striking water jackets!
The exhaust valve opening is ready for the lead free
seat. The size of the hole is 35.5 mm
The Mklll Zodiac head is ready for the lead free
seats.
Anders is
preparing the right size of the seat - both inside (29.5 mm) and outside (35.7
mm). Some machinists will turn the inside angle now while the insert is fitted
in a lathe.
Washing the head to warm it up.
The finished lead free seat insert.
Anders has frozen the lead free seat (to shrink it) and then he knocks it into the head.
Freeze
spray. Dry ice can also be used. Do be careful near your skin.
The left
exhaust is ok - the right one is the next to go.
Volvo valves from a B-20 about 1969-71. The stem is 7.95 mm - a little thicker than the Mklll Zodiac stem. it was therefore not necessary to use valve guide liners, (just a hone) and I could use the original retainers and rubber valve seals. I had to buy new keepers.
The inlet valves being prepared from 42mm back to original 40mm Mklll size. The original angle on the head is 30`(angle). the volvo valve is 45`(angle). So the head has been prepared from 30` to 45 `(angle)
Measuring
the valve.......
.......to suit
the seat
Ready to prepare the lead free
seats.
Preparing the lead free seat insert.
Moving along.........
All the valves in.........
Checking
the valve heights.....he is a professional, I'm impressed!
Preparing the head for........
........Level
He took 0.05mm of the head.
Anders
the professional himself with the finished result.
Thanks to
Håvard Bækkevold and Anders Kråbøl for taking
photos
and writing the notes for this to help other members.
Disclaimer:
The advice and guidelines given in these articles are given in good faith.
The owners and managers of the Galeforce Zephyr site will take no
responsibility for any injuries or loss sustained while carrying out the
described tasks and procedures or any consequences arising. Please read
the Safety First
Article