new strange tapping
tapping could be a number of things.....i think either a lifter or a bearing getting ready to fail.....mine ran crazy fast before it took a ****....fired it up in the parking lot for a couple of people and then the tapping/squeeking/slapping sound started.....it was hit or miss when it would happen....i know you have fresh oil but is there any metal in the oil.....if not try to add some lucas
This happened last week:



I think I broke a rod and **** it out of the side of the block. Maybe a piston pin let go or something...I still have yet to tear it apart. Hope yours isn't that serious!
Like you said, it sounds like it's coming from the bottom of the motor, so there's no way to check it without tearing the motor apart.

