wp_verify_nonce is always false even when the nonces are identical

Nonces don’t store absolute time, but the number of ‘ticks’ since the start of the unix epoch, where each tick is half a day long by default. To check a nonce, WordPress generates the current and previous nonces and compares the result to the value you passed in.

This means that the nonce lifetime needs to match at the point you create the nonce and at the point you verify it. You could implement that using your filters again, e.g.

add_filter( 'nonce_life', 'noncelife' );
$valid_nonce = wp_verify_nonce( $nonce, 'timform_nonce' );
remove_filter( 'nonce_life', 'noncelife' );
if ( ! $valid_nonce ) {

(‘store’ is probably the wrong word: they’re actually hashes of a constructed string. There’s no way to extract information from a nonce the same way there is from an encrypted cookie.)