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Technical Corner - Engine Build Part 1
Engine Build Part 1
The Bottom End

In the next series of articles we will detail the building of our VQ35 DE based race engines.  First will be the bottom end.  We have built these engines to a variety of specifications.  The bottom end we are discussing here is a naturally aspirated 3.7 liter variation that will provide about 450 horsepower at 8600 rpm and should be reliable for endurance racing.

VQ 35 DE Bottom End BlockAfter acquiring all the parts for the new engine, the crank and pistons are measured and weighed.  We use a trusted machine shop to bore and hone the block and balance the rotating assembly.  We measure and calculate the bob weights in-house and hold a less than 1 gram tolerance on the balance.  The final hone is held to a +/- .0002 tolerance and the finish is specified to suit the particular ring package.  When the parts return from the machine shop everything is double checked and cleaned.  Any additional modifications are performed in-house.  This block required machining for clearance to accommodate the larger stroke and required removing and plugging the piston squirters.

VQ 35 Block with Crower Stroker Crankshaft

We keep a range of main bearing sizes in stock and variations in manufacturing allow us to pick and choose bearings to achieve the desired bearing clearance.  The Crower Stroker  crank is laid in the block using Red Line Assembly Lube.

VQ 35 ,Crower Crankshaft, ARP studs

We use ARP studs to retain the main caps.

VQ 35 bottom end assembly

The aluminum girdle is installed and all the studs are torqued.  The crank is spun to confirm that everything is up to standards.  The crank must turn with no resistance or variation in the feel.  The general policy when we build an engine is to measure and confirm everything and keep it extremely clean.  We assemble our engines in a dedicated clean assembly room.

VQ 35 grinding the rings for proper fit

The rings are measured and individually ground for proper fit.

Electric ring grinder VQ 35 Nissan 350Z

A few years ago we acquired this super slick electric ring grinder.  The precision and ease of use of this grinder has made one of the most tedious jobs on the engine into one that is now somewhat enjoyable!

Hand finishing rings on VQ 35 engine

The ends of the rings are hand finished and inspected.

BC rods, CP pistons, Cosworth bearings

For this engine we are using BC rods, CP pistons, and Cosworth bearings.  As with the main bearings we stock a range of rod bearings and measure and select each bearing to achieve the desired clearances.

VQ 35 piston assemblies installed in block

The piston and rod assemblies are installed in the block.  Years of experience by our engine builder insures that everything has the right "feel" as each component is installed.

measuring rod bolt stretch VQ 35

For ease of work we have machined an old girdle to give us some convenient spacers to hold the crank assembly in place while we torque the rod bolts and measure the stretch.  The rod bolts are torqued to achieve a specific stretch number and the torque required to achieve that stretch is recorded.  Great care is taken to maintain these records over the life of the bolt and rod.

Aluminum girdle VQ 35

The aluminum girdle has been machined for stroke clearance.

Complete bottom end VQ 35

The complete bottom end is assembled, everything is torqued and the main studs are installed.

VQ 35 Nissan 350Z engine bottom end

The force required to turn this assembly is measured and recorded.  This bottom end is now ready for the top end components.