Im hoping someone can help me with this. I have an 85 250sx. The engine just started making a clatter sound from the top end, it only does it when its cold after about 5 minutes when it warms up its fine, no noises and it still runs just fine. All help would be appreciated.

Thanks Dale

 

Could be several things , cam chain tensioner slipping , camshaft / rocker arms worn , to the oil just changed using a cheap no-name oil filter and installing it backwards ..