I have had 2 22re's (86) that have had a similar sound when cold. It turned out to be piston slap. There ia a Toyota service bulletin from that era that addresses it. The fix in the bulletin was changing pistons to an updated designed piston that had the pin center offset slightly from the original. The slap never seemed manifest itself in any way other than the sound (which drove me crazy) After a few minutes (pistons expanded some with heat) the sound was gone. Also, the slap was only heard on acceleration (even light) and not at idle. A possibility...

^2x