This weekend i set about re-shimming the cylinder head...
Tools and parts required:
Feeler gauges (0.05 to 1mm blades)
Micrometer or Vernier Calipers
Shim set (in my case, a set of spares from previous engine)
The valve clearances were measured:
Nissan specify a hot engine checking clearance of INLET 0.21 to 0.49mm, EXHAUST 0.30 to 0.58mm.
To be fair, you can see my clearances werent too bad. But i wanted to minmise the annoying tapping noise from the valvetrain so aimed to gap them to 0.2mm. My feeler gauges only measured in 0.1mm increments after 0.2mm so measurements werent 100% accurate, but at least allowed me to see which ones were between 0.2 to 0.29mm, and those that were 0.3mm or above.
I then set about reshimming those that were 0.3mm clearance or above. All of those shims measured inbetween 2.38 to 2.44mm thickness. These shims were replaced with what spares i had available, using larger shims ranging from 2.47 to 2.51mm.
6 shims were replaced on the exhaust side, and 2 shims on the intake..
You can see the replaced shims here (those with no oil on them):
JWT S1's back in and timed up:
Clearances were rechecked after, resulting in 0.2mm clearances across the board.
End result?
Its smoother, quieter and most suprising of all is the performance difference, you probably wouldnt believe me if i said i was seeing boost at least 500rpm sooner, but yep...thats whats happened and i'm chuffed to bits. In fact the performance is so different and eager to make boost low down, that im getting a small amount of compressor surge at low rpm and that initially resulted in lots of tyre smoke through 2nd gear, which then ended up being clutch slip shortly after :thumb:Oh well..STAGE 4 Clutch coming soon.
I also splashed some paint on the VC too: