Building the Nissan VQ37VHR!

The XPC bearing’s P-max Black material is a tri-metal bearing with steel, a very high capacity copper based intermediate layer and a softer lead-based overlay that contains 5% copper and undergoes a proprietary hardening process for industry leading load capacity. C in XPC denotes King’s new copper nano-particles based coating which further increases load-bearing capacity while reducing friction and providing improved wear.

In addition, the King main bearings have elliptical oil holes, undercut oil grooves for  maximum  bearing area, a very tight crush for optimal heat transfer and solid retention and an eccentric ID to help form and maintain a hydrodynamic oil film easier.

One of the weak points on the VQ engine when run at high rpm is the oil pump gears.  When approaching 8,000 rpm on a VHR and HR engines they tend to fracture.  Other VQ’s have experienced failures at even lower RPM. A lot of the failure issues are due to the weak sintered metal material of the stock gears and the asymmetrical rotor tooth profile that is done for lower NVH. This tooth profile makes for pointy areas in the outer gear that are areas of stress concentration where the outer gear cracks.

The JWT oil pump gears are made of much stronger billet chrome-moly steel and have symmetrical teeth with a much more rounded profile for less stress concentration. This makes for a much stronger gear that has been tested in racing up to 9,000 rpm. In addition, we WPC treated the gears to further improve the fatigue strength.

For naturally aspirated engines that are not subjected to as extreme cylinder pressures, we normally stick to OEM torque to yield head bolts.  This sort of bolt results in less bore distortion and improved ring seal at operating temperature when the block has fully expanded. We did use the strongest of the Nissan OEM torque to yield head bolts with the most thread engagement, the ones off of a Nissan Juke.  These are the best possible bolts for this sort of application.

We can manipulate the VVEL system on the intake side of the engine through tuning the ECU.  However, the exhaust side of the engine still uses a conventional camshaft.  We used JWT’s exhaust cam part number A3709-EXHC2.  It has a duration of 272 degrees and a lift of 11.7mm or 0.461 inches.

We got a set of JWT’s adjustable exhaust cam timing gears part number AVQ35-EGEAR.  These will allow us to adjust the exhaust cam timing in 8 steps of 2.5 crank degrees each step.  Now we will be able to adjust the cam timing if needed to make up for things like align boring, decking the block and the head, all of which can make the cam timing retard.