After a quick M40 gearbox swap, my engine began to run really badly.
I know it makes no sense, but that's how it coincided.

I was getting a lot of new valve noise. That coupled with my consistently poor fuel economy made me suspect that my valves might be in trouble. I adjusted the valve lash back to .018, but things only got worse and sounded horrible. The clearance was not all that far off and I don't have a sense that my valves are starting to rapidly recede.

So, after a 1-day commute and concerns about things flying apart, I decided to try swapping my B18B head out for another B18B head. That whole operation went by pretty easily, except that my heater capillary tube was frozen. I turned the head around a few times to try to relive the "twist" on the tube, but I was quickly rewarded with a light hiss and the smell of raw ether...dang.

I know what that means, so don't bother explaining it, unless you know how to fix it. I *think* I have a spare temp gauge, but I foresee this being a problem again. I saw a photo floating around where somebody put an electric temp gauge in the 120 cluster. Does anyone know anything about this Mod??

The new head is on, and the valves still chatter, but it is "different" now. I have not yet adjusted the rockers for the new head.

I followed the procedure in the VClassics article for valve clearance adjustment, but I found it a bit confusing with the "adjust intake valve #4, when #3 is just starting to open"...? or somesuch. I freely admit I may have done something wrong here. I recall that the article used to be longer...
Can anyone point me to a very explicit guide as to which valve to adjust in which sequence??

The chatter with the replacement head is quite noticeable but the whole engine seems to run a bit better. I think the chatter will quite down when I get the valve re-adjusted. It got too dark and cold for me to try and adjust the new setup.

Weirdly, the original head appears to be okay. Nothing looks especially off or different, but this may not be a problem I can easily "see." Are there any particular signs of trouble I should be looking at??