One of the many issues with the ka24de is that it has a long stroke. At the same time a lot of people love that stroke because it gives you the sensation of torque that a lot of us enthusiasts love at the low end of the power band. A lot of domestic engines prefer staying naturally aspirated and go with a longer stroke and increase compression. Those engines are typically small block or big block V8’s. When you apply the long stroke to an inline 4 cylinder engine, it causes more vibration on the rotating assembly, a varying number of distortion forces which act on the crankshaft. The forces are increased when you expect higher revolutions and when you force induce the vehicle.
To counteract those distortions for extra twisting forces on the crankshaft, race type crankshaft manufacturers and good engines on oem cars come with a fully counter-weighted crankshaft. This means that the force exerted by each Rod and piston is counteracted by a weight which opposes the force. This allows the rotating assembly to have greater balance and less dynamic stress. Remember those Merry Go Rounds that you used to swing ride and swing on as a kid. Every Go on one with a fat kid on the other side? The Merry Go Round starts not only spinning oddly but the weight shifts, the forces change, and you get thrown off.
I picked up this sweet piece of kit a while back. Brian Crower made an initial batch of these custom Fully Counterweighted Crankshafts for the KA24DE. I hope this piece will be one of the fundamental pieces of the engine build and it not only is it a better product than what is provided by Nissan, it will provide my engine with greater stability at speed and allow it to have a larger powerband than traditional KA24De’s.
Here is how the tradition KA24DE crank compares to the new Brian Crower Crank. The New Crank weighs heavier than the oem crank due to the added counterweights.
Weight: 34 lbs.
Main Journal Diameter:
Pin Journal Diameter:
Journal Taper: less than 0.002mm
Journal Out of Round: less than 0.005mm
Free End Play: less than 0.04mm
Main Bearing Clearance: 0.020-0.047mm
Connecting Rod Bearing Clearance: 0.010-0.035mm
Material: 4340 Billet Steel
Weight: 45 lbs
The diameter of the counterweights is 6.520″.The distance from the
centerline of the main -3.260″
( the above is for the 102mm stroke crank -the 96mm will 3.142″ from the
centerline of the main.)
Rod Journal Diameter: 49.96-49.97mm
Main Journal Diameter: 59.96-59.97mm
The cranks are fully balanced within .5 grams.
If you check out the BC website. They now stock this item and I believe they have it available. LINK Contact Dustin @ BC. firstname.lastname@example.org