Complete Machining Package
Hello, welcome to our shop! Let us walk you through our complete blueprinting process start to finish. Subaru blocks are not like all engine blocks, and need particular attention, and this is why our Subaru specific engine shop came to be. At SubaruMachine.com, all of our blocks go through the same complete reconditioning process, regardless if you buy the case outright, or if you send yours in for service. All blocks are measured, pressure tested, Magnifluxed, vapor blasted, squared up by the main bore, diamond resurfaced, torque plate honed, debured, individually numbered, measurement inscribed, quality control inspected, blueprint sheet, professionally packaged, and shipped to your door.
1. Core Check In, Ultra-Sonic Cleaning, and Pressure Testing
Once your core has arrived, we check in the case and do a initial visual test for shipping damage. We then measure and record the bores sizes to identify which pistons to order (either .010", or 020"), measure main bore straightness, and then hot tank the cases. Once ultrasonic cleaned with simple detergents; we then pressure test the case with our custom pressure testing fixture plates. This pressurizes the case to low PSI for a physical pressure test in the coolant jackets to identify a cracked cylinder. Soapy Water is applied and pressure gauge is set to monitor pressure drop. We also magniflux the actual cylinders with magnetic powder to check for stress cracks on the cylinder. Once your case passes these tests, it is now deemed good for machining.
2. Custom Piston Selection
Now that the core has passed our quality control checkpoints,it is time to decide which pistons are need for the project. You will hear a lot about Forged Pistons being better for performance, but they wear much much faster (40K Miles). Your high HP goals may require this type of maintenance, as these soft but tough pistons SWELL with heat. We MUST machine these cases with extra "Cold Clearance" to make up for this heat swell. This means we add clearance to the between the piston and cylinder as required of the piston manufacture. As the engine warms up, the piston will grow (</>.0025") into proper P/W spec (.0012"). Cast Aluminum and Hyperuetechtic Pistons are highly recommended if you plan on putting miles on the engine. These pistons do not grow and swell like forged aluminum, and have less of a tolerance to extreme heat. These pistons are machined to AERA Spec, which is very very tight tolerance. (.0004"-.0012" +/- .0004"). This is TOTAL piston to wall clearance, meaning this is divided by 2, and not multiplied by two when doing piston diameter to bore math.
3. Vapor Blast and Fresh Water Rinse
To create the best finish for the block, we vapor blast the aluminum case halves. Vapor Blasting is a water / glass bead media finishing process. We do this process in house, and creates a amazing finish to the aluminum case. This process is very helpful in removing plug thread glue, rtv, and crusty calcium corrosion that the hot tank and ultrasonic simply would never remove. Once dry, we blow out every thread and cavity extensively with compressed air, ensuring no blast media is left anywhere in the block. An important note about blasting and these Subaru blocks, is that they are very open and do not have a blow molded casting, like a cylinder head water jacket. What I am trying to explain is that Subaru blocks do not hold "hidden sand" and are entirely an open casting, and not as high of a risk as other types of blocks, so rest assured there would NEVER be any blast media left in our blocks.
4. Squaring Up the Block to the Crankshaft Centerline
Once the cylinders are complete, we send the case over our surfacing machine. We square up the deck surfaces to the the centerline of the crankshaft, and not the parting case halves. We match how much we cut for each side, so the case CI matches on both banks. We use a 3/8" round CBN insert, on balanced fly cutter, which results in a low RA finish. This way you have the smoothest surface for the MLS head gasket.
5. Boring and Torque Plate Honing of Cylinders
Now that we have a squared block, we can start machining cylinder bores. We start the process in our Van Norm boring machine. This is where we bore out 85%-90% of the actual cylinder, leaving around .003" of material for the honing process. We then move the block to our Kwik Way Power Hone, where we install the torque plate, and proceed to our 3 step precision honing process. If .25mm or less material is taken from the cylinders, they are simply toque plate honed; and we skip the boring process all together, because there is not enough material to bore. We start honing the cylinders with a roughing stone, and work our way to the final finish stones. Our cylinders are concentric within .0001", along with cylinder straightness top to bottom, is within .0001".
6. Case Deburring and Oil Galley Porting
The Subaru cases almost all have oiling gallies that can be improved with hand porting. During this process we port the oil pump casting. This helps eliminate oil turbulence into the oil pump, allowing for better oil flow. We also hand chamfer the case sharp edges around the decks and bell housing.
7. Engraving Data and Final Wash
After we have finished all the machine work listed above, we hand engrave the data onto the case, and give it a hot soapy water wash. We remove all metal shavings and honing residue; and pipe cleaner all galleys. Once the block is 100% clean, we coat the cases with light fogging oil to prevent flash rust during shipping. This oil must be washed off before assembly; as tagged on all of our cases.
8. Spec Sheets and Quality Control
No case is complete without proper quality control. Final ID Bore Spec, OD Piston Diameter, and Piston to Wall Clearance are among the many measurements documented at Q/C. All of the information pertaining to the project is documented and inserted to project folder which is included with every SubaruMachine.com case. In short, we document that the case is pressure tested, crack detected, ultrasonic cleaned, vapor blasted, bored, torque plated, honed, CBN resurfaced, individually numbered, hand washed, and documented on paper to AERA or Piston manufactures specs.
9. Packaging and Shipping
The case is now placed inside our double shipping box, lined with 2" of styrofoam. This is to comply with Fed Ex shipping insurance policy, that all packages must have 2" of padding between the product package and the shipping package. Our product package contains the already bagged case, which is inserted in another poly bag and expanding foamed into place. The case is now securely packaged and will not bounce around inside the box while in shipping. Pistons and documentation is inside the shipping box securely in place. Our shipping, packaging, and machine process are designed to eliminate all headaches and risk involved in ordering a specialty item online, and we strive for zippy turn around and excellent customer service!
10. Arrival and Unpacking
We saved the best for last! When you open your case and check out the goods. We package all of our paperwork away from box opening so you will not cut the paperwork in half. The cases with warranty tags attached. DO NOT DESTROY or DISCARD PACKAGING. You may need this if you find the case is damaged in shipping or any warranty reason. Read and follow all unpacking and case prep instructions before you begin your build, as gapping rings, inscribing parts, can void returns on the piston set, even if there is an issue with the case itself. Our cases are guaranteed to be in spec as advertised, and you can read more about all of our warranty information online and is included within the paperwork included with the case. You are now on to a successful Subaru engine assembly project, and we hope you enjoy using our product!