Recently I noticed VTEC engagement sounded weird occasionally on my B18C1. I had recently changed the oil with Mobil 1 5w-30, and a Mobil 1 oil filter. I checked my oil level it seemed about a quart low. I thought this is odd..., so I added oil and VTEC engagement returned to normal. So it seemed. The apparent oil burnoff was in the back of my mind. About a week later I believe I was in fourth gear and was attempting to shift to fifth. I believe I shifted to third. I quickly pushed the clutch pedal down. Then I heard tapping. I drove home sobering up from the realization that I FU*KED up. I've spent the last two weeks thinking and listening to the engine. It idles fine, just as it always has. It just sounds embarrassing. So I and a few people pulled the valve cover off a few days ago and immediately saw 4 tappet adjusting nuts not on tappet adjusting screws!!!! One of them was found sitting next to the valve. The other 3 are unaccounted for. A D16 donated 3 replacements. This seems to explain the apparent oil consumption. I'd like to hear from others who have experienced this and what they did to solve the issue. I plan on doing a compression check and valve adjustment very soon. Right now the B18C1 still sounds awful. In the photo below you can see the nut is missing.

 

You need to find all the missing nuts. Fish around the head with a magnetic pickup and drop the oil pan. You do not want nuts floating around your engine.

Re-do the valve lash and this time torque all the tappet nuts to spec.

 

Thats scary that you waited so long to take the valve cover off and see if you could tell what the cause was. GL hope you find the other three nuts.

 

The valve clearances and tappet nuts were adjusted. Everything seems normal again. Next, I will drop the oil pan, to hopefully find the missing tappet adjusting nuts.

 

Yeah I wouldn't start that engine even for a minute until I found all 3 missing nuts, no matter how much I had to tear the engine apart to find them.