Compression Test - Spark Plug inner diameter

[Makaveli]

I am planning on doing a compression test, my one came with 5 different fittings.

10mm, 12mm, 14mm long, 14mm short and 18. Thats for inner diameter of the spark plug for a 1zz-fe engine.

Which one should i use?

Thanks

[ee904age]

14mm from memory, but if not, whichever one fits.

[Makaveli]

Yeah thats what i thought 12 or 14. I will try the short one? Because apparently long one can damage the piston....

[Bling]

use the one the length (or shorter) of ya spark plug maybe?

or get someone who knows about cars to do it.....