"ting" noise when turning the crank manually

[Stripes]

I just finished swapping heads on my sr and as I was turning the crank over with a ratchet to get the chain in place for the timing I would hear this "ting" noise coming from what sounded like the pistons.The chain was not connected to the cam gears at all, and I had all the cam bolts loosened so that the cams were not putting any tension on the rockers; this way I wouldn't have to worry about the pistons hitting the valves while turning it over.Whenever I heard the noise I would check to see where the pistons were and the were all about even at the halfway point.

The sound does not ring out and it is more of a low pitch than anything. The motor has never knocked or anything either.

Has anyone heard this before and is it normal? Can it be because of turning it over with no oil in the motor and the pistons bottoming out?

edit* I got curious and just took the head off. I guess that's just the noise the pistons make when cycling, no problems found at all
Modified by Stripes at 11:38 PM 10/29/2009