Title_save_pre – Simple problem that u know for sure

Try the code below. Filter’s take a value and returns it afterwards.

  <?php
    function muda_titulo($title) {
    global $post;
    $type = get_post_type($post->ID);
    if ($type== 'event') {
    $title = $post->post_excerpt;
    $day= get_the_time('l, d F, Y');
    return $title.' - '.$day;

    } else if ($type == 'post') {
       return $title;
    }
    }
    add_filter ('title_save_pre','muda_titulo');
    ?>