After finishing the bottom end rebuild, I'm now looking at which N42 head to bolt on top. One is completely standard but the other has th following mods;
Head skimmed by 0.9mm
Cam towers shimmed by two 0.01 gaskets ( front and rear towers), no gasket in the middle tower and one on the others
An E30 cam with CE674A and 110 degree ( well the symbol for it anyway) stamped into the end of it
Standard 1.2mm head gasket, rocker arm adjusting screws have about 10mm of thread visible.
Does anyone know what the number relates to ( did a search and nothing came up) and what sort of grind the cam has? It's a street car on SUs and extractors.
When I dismantled the engine, all six of the top piston rings were cracked. Was told that was likely due to detonation. Does that make sense and is that a timing fuel error or something else?
There were no marks on the valves or piston crowns.
All help appreciated
Cheers