Honda Civic Engine Problems

Your engine is an all-alloy unit with hardened valve-seat inserts in the cylinder head, so it will survive on a diet of unleaded fuel without a problem. If you're concerned about it, have your valve clearances adjusted to specification, then run the engine on unleaded for six months or so and recheck the clearances. If there's little change, a thousandth of an inch or so, it's fine and you can keep running on unleaded. If the clearances reduce significantly, by three or four thousandths of an inch, then go back to running it on LRP or have the head fitted with new, harder valve seats that are available at most cylinder head specialists.