1G Trouble shoot assistance needed

[Alpha D]

4season. The motor supposedly was rebuilt by chimm and his brother. The turbo was from jhaan dude. A few things could have been improperly installed. If the rings are faulty the pistons would need to be pulled. Correct? if it is the valve guides the head will need to be pulled. This is not a to big of a job. Anything regarding the block will be terrible. Due to the fact i do not have the garage space or proper tools. Excessive bearing clearance i would really be in trouble. In order to check the lower bottom end i would pull the oil pan correct?