After running into dead ends with my misfire I decided to open my Rover back up. When I did my HG/oil pump job about the only thing I didnt replace was the rocker assembly and camshaft. I tried to clean the rocker assembly myself but did not do a good job. I spoke with a Rover mechanic who suggested it may be the camshaft as well.

So far Ive stripped it down to remove the rocker assemblies. The oil ports where the push rods sit were mostly clogged. My question is whether or not this could be my misfire culprit, or should I tear it apart further to inspect the camshaft?

 

Any thoughts on limited oil flow through the rocker arms?

I think I'm going to go ahead and pull the camshaft. I'd rather not question it in the future.

 

What do your spark plugs look like when laid out in the shape of the motor?

 

Front of the engine is the bottom of the picture. #8 (my misfire) is the cleanest. Most have a wet appearance. #1 appears to be dry though. Just as a note, before I tore this down I ran some BG EPR through the oil, this has knocked off some of the oil residue I've seen around the heads. I don't know if it would have thinned out the oil? The plug threads did appear to have oil sludge on them, more than I've noticed before.

 

Wet deposits covering the white ceramic suggest either a head gasket failure OR piston ring trouble:
www.youtube.com/watch?v=uMYAEtxiYfc

 

I've had a long history of troubleshooting this misfire. Currently the plug in the misfire cylinder is the cleanest one without wet deposits. In the process I've replaced O2 sensors which could have been causing a rich condition?

Right now I've got the Rover tore down to the heads. The lower intake and the rocker assembly is removed. I could re-run the compression test in this state to check for piston ring problems couldn't I?