posted on September 27, 2009 21:40
Jim Wolf Technology Releases Nissan VG30DE/DETT Mechanical Cam
MotoIQ Staff Report
Jim Wolf Technology has introduced their mechanical cam for the VG30D series NissanV6 twin cam engines. JWT’s mechanical cam is the biggest, most aggressive and the most powerful VG cam on the market. The JWT mechanical cam has the most area under the lift and duration curve for the ultimate in volumetric efficiency. Area under the curve is what makes power and torque and is more meaningful than simple lift and duration numbers.
This unique cam solves some of the problems that have been holding back the VG from making serious power. Although the VG uses direct bucket lifters which are usually pretty light, it also has hydraulic lash adjuster built into the lifters. Nissan did this to make the VG’s valvetrain maintenance free. The hydraulic lifters are heavy and contain oil which also has a lot of weight.
This weight can contribute to valve float. The hydraulic lash adjusters also pump up at high rpm and keep the valve from seating properly. When revved past 8000 rpm, a VG will float its valves, and then the lifters will pump up, holding the valves open. The engine will not run properly for several minutes after this. If the car is continued to be driven hard with the valves not closing completely, damage to the engine can result.
The JWT cams use lightweight Tomei mechanical bucket that uses shims under the bucket to adjust the lash. Although setting up these lifters is somewhat time consuming, the light weight allows higher revs and a more aggressive cam profile with more area under the lift curve. A lighter valve spring can be used that has less friction as well.
The JWT cams do require a more involved shim fitting procedure set up to adjust lash and have such an aggressive profile that the cylinder head casting must be notched on either side of the lifter bore to clear the lobe, but for a highly modified VG, this cam will prove essential for making the ultimate in power. As a note, the newer VQ and QR engines all use mechanical valve actuation and select fit buckets to adjust the lash so this is not a radical thing. Most performance motorcycle engines also use a similar system to adjust lash as well.
Look for us to do a full evaluation of these cams on one of our project cars in the near future.