- Strip intercooler (if top mount) plug leads and rocker cover,
- Measure clearance between rocker arms and cams as described in the service manual..
NB.. the service manual says to measure the clearances hot!
I take the same view as Ian at HiTeq when I was discussing this with him that its far better to measure the clearances cold! briefly the reason is metal expands with heat, generally the hotter the more expansion, though this isn't always linear (different metals also expand by different amounts per deg of temperature rise). Unfortunatly the service manual doesn't specify a temperature to measure the clearances at and short of sticking a thermometer in the top of the engine its just not practical to do so if you do it when the engines cold (ambient temperature) you stand a better chance of getting more accurate, consistent results and therefore a quieter engine! apologies to all if thats getting a bit technical...
- remove spark plugs (this will enable you to turn the engine more freely)
- for any clearances that are out of tolerence, rotate the engine so that the camshaft lobe is vertical and the valves are closed. The rocker arm should be at its 'freeist/loosest' point.
- remove the rockerarm retaining spring.
Now you need an assistant with very strong fingers....
- from the front of the engine (valves are in pairs) push the valve that has the rocker arm guide on it down (left hand valve of the pair) - you don't need to compress it fully (about 2/3mm) is enough, the rocker arm can now be rotated anticlockwise and you can remove it.
- use the same procedure to remove any other rocker arms that clearances need adjusting on...
- measure clearances, shims and guides as in the service manual
- refitting is the reverse of removal (rocker arm retaining springs are a bit fiddly) remember to lubricate all components with oil on reassembly..
- also remember a new rocker cover gasket (is the same as the 2.0 primera and about £4 from a motor factors..
- Enjoy your quieter SR20DET ;o)
