Technical Advisor is DP Engine Parts’ reference hub for building and machining with our pistons, rods, and rings — practical, print-and-use tools and specifications, not marketing copy. Use the Technical Advisor menu above to open any of the three tools below.
Compression Ratio Calculator Monitor
Enter bore, stroke, head gasket bore and thickness, combustion chamber volume, piston volume (dome or dish), deck clearance, and — optionally — rod length, RPM and cylinder count. The calculator returns your static compression ratio live as you type, along with the full breakdown behind it: swept volume, head gasket volume, deck clearance volume, total clearance volume, rod/stroke ratio, piston mean speed, and total engine capacity. Use it whenever you’re planning a build and need to know what compression ratio a given piston, deck height, and gasket combination will actually produce — before you commit to parts.
Piston Ring Gaps
The correct ring end gap for a build depends on two things every time: the engine category (Turbo, Turbo Race, or Aspirated) and the cylinder material (Cast Iron or Aluminum). This page gives the exact formula and factor for each combination — 1st ring, 2nd ring, and the oil ring’s flat minimum — plus a worked example and the ring gap position diagram showing where each gap should sit around the piston relative to the wrist pin. Use it any time you’re gapping rings, whether for one of our kits or a customer’s own combination.
Bore Preparation
Covers the full cylinder honing procedure from setup through final check: torque plate use, roundness tolerance, the honing sequence broken down by ring face material — Gas Nitrided, Moly, Chrome, and PVD-coated — each with its own grit sequence, crosshatch angle and target surface finish, plus the crosshatch pattern diagram itself, the plateau finish pass, and the cleaning step most shops skip. Use it before final assembly on any rebuild, and always in that order: hone the bore first, then set ring gaps per the Piston Ring Gaps page above — bore size and cylinder material feed directly into that formula.
How the three fit together on a build
A typical order is: use the Compression Ratio Calculator at the planning stage to confirm the target CR before parts are cut or ordered; once the block comes back from the machine shop, use Bore Preparation to hone the cylinders correctly for whichever ring face material you’re running; then use Piston Ring Gaps to set the actual ring end gaps on the finished bore before final assembly. All three pages are built for quick reference on the shop floor — bookmark whichever one applies to the job in front of you.