Comprehensive Engine Building Steps

Disassembly & Diagnosis

Our rebuilds start by performing an “autopsy” on the old motor. We determine what went wrong, and why (cause of death) and if any parts are reusable or could be reconditioned. We work with the customer to determine the best plan forwards to achieve their goals, and what realistic costs and timeline will look like.

Quoting & Contract

Once the engine has been evaluated we communicate the list of what needs to be done to our client. We are able to finalize an accurate number for our quote, proceed with our engine building contract, and send out a deposit invoice. Deposits are 50% upfront for engine building services.

Cleaning

The engine block gets washed in a commercial hot tank before and after machining. We remove all plugs, hardware, broken bolts, and fluids. The crank gets hot tanked before and after machine work. The cylinder heads are disassembled, cleaned, and inspected.

Machine Work (Engine Block)

Flag Motorsports offers in-house comprehensive machine work for our engine blocks. Most engine blocks will receive a torque plate hone, sized to the selected pistons. The block will be surfaced, with new cam bearings installed. Main journals are checked for straightness and roundness with a dial bore gauge. If necessary, a line hone will be performed. Lastly, the block will be cleaned for a final time and prepared for pre-assembly.

Machine Work (Cylinder Heads)

All cylinder heads undergo detailed machine work processes. They are surfaced for straightness and desired compression ratio. Porting is optional, and performed by a CNC machine. Flag Motorsports also offers an optional bronze guide upgrade. Valve jobs for cylinder heads are standard 3 angle, or optional 5 angle valve job. Valves themselves will be reconditioned, replaced, or upgraded depending on the engine and application. Rocker arms are checked and trunnion/shaft upgrades are available.

Machine Work (Rotating Assembly)

The crankshaft is polished and sized for precise clearances, as well as precision balanced to within 1 gram. Connecting rods are resized, with the big ends sized to proper housing bore spec +/- .0002 roundness. Small ends are sized to proper wrist pin size and all rods are weight matched to within 1 gram. Rod bolts are checked for stretch, and replaced or upgraded. All rotating assembly components get measured and matched to each other to ensure each crankshaft journal is matched to within the tightest range possible.