Regarding the cylinder bore grade letters

[sujitroy]

Mentioned in the Triumph V8 engine training notes. it mentions cylinder bore grade letters.

Does anyone know what the letter stand for? I have F and G stamped on my replacement block no. 80.
Sujit

[Westfaling]

The letters refer to different sizes of piston fitted. As the bores were not machined all that consistently they compensated by having different diameter pistons.

[KOY 23]

The grades are listed in the ROM.

[Motorsport Micky]

Mentioned in the Triumph V8 engine training notes. it mentions cylinder bore grade letters.

Does anyone know what the letter stand for? I have F and G stamped on my replacement block no. 80.
Sujit

Academic interest only, measure your liner bores and compare against your pistons (they are not round, measure in two planes to establish max dimensions) to establish wear and if within limits.
The grading of bores and pistons and many other items where complimentary running of components are required is commonly done in engineering (even in todays much more advanced world !). The liners are likely graded against pistons on the inside dia and against the liner block bored dimensions on the outside dia. Because all these components are machined in vast numbers and tooling wears as it machines them (often measured in microns) "batch engineering" practices are adopted where the completed items are micro examined and graded accordingly to give the best results when matched with the similar complimentary components, in this instance pistons with cylinder liner bores.

Micky

[sujitroy]

Good to know. Thx