Engines

Short Blocks

Each core is inspected upon initial teardown for spun bearings, oil starvation, severe overheating, and other damage before any work is performed. If it passes this test a chasing tap is run through the main, head, and front case bolt holes in the block to ensure proper torque reading on assembly. After this the engine and crank are cleaned in a hot tank and then the block and crank are both magnafluxed to check for cracks.

From there the crank is polished and on race motors the crank, rotating assembly, and reciprocating assembly are balanced within 1 gram. Then the main bores of the block are align honed. This procedure is important, because when a block is cast and machined internal stresses develop, as a block is heat cycled the metal will “relax”, and after a period of time take a final set. During this process the main journals will shift from their “as cast” machined position, and as this is an extremely slow process the bearings may actually wear to accommodate the change. When the main bores are align honed you are assured that the bores are perfectly straight with each other and are a true circle. This makes for longer main bearing life and reduced friction in the motor. Next the block is decked to ensure the best head gasket seal and finished under 50ra for use with Cometic or Mitsubishi MLS head gaskets.

Then the cylinders are over bored and final honing is done with a torque plate installed on the motor. Use of a torque plate ensures that bores are true when a cylinder head is bolted in place. The head hardware pulls the block outward when torqued down; this doesn’t allow the rings to seal in each four spots in the bore where the hardware is located. Remember that this is at the top of the bore where cylinder pressure is in the thousands of pounds per square inch and ring seal is the most critical. We own and use a BHJ “r” torque plate and ARP hardware replaced every three motors to ensure consistency. We are the only shop in Washington to offer this service.

After the machine work is done the block and crank are thoroughly cleaned to remove any machine chips or other bits of metal, and the cylinder walls are also wiped down with ATF to remove honing grit left on the wall. Then everything is moved to our dedicated clean room, used only for motor assembly. This makes sure that no dust, dirt, or grime finds its way into your new motor. All clearances are double checked for assembly and rings are file fit (forged piston motors). Everything is assembled using ARP moly assembly lube to reduce any chance of wear on initial startup.

Once assembled the motor is packaged for shipping and a spec sheet for your particular motor is printed out for your records.