Straight Edge for Flat Surface Measurement RT-800 - Chinelatto 34 inches

The flat surface measurement ruler is used to check if cylinder heads and engine blocks are perfectly flat after resurfacing. The RT-800 model from Chinelatto allows identifying warping, scratches or unevenness that compromise head gasket sealing. With 34.25 inches (870mm) length, it handles engines of different sizes, ensuring the surface meets specifications before assembly.

The RT-800 ruler measures 34.25 inches (870mm) length, 3.35 inches (85mm) height and 1.97 inches (50mm) width, weighing 20 lb (9.1kg). It's manufactured from normalized GG-25 cast iron with ground surface for maximum precision. The double T profile ensures structural rigidity, preventing flexing during measurement. These dimensions allow measuring cylinder heads and blocks from small to medium engines with total reliability in the shop.

With 34.25 inches (870mm) length, the ruler handles most automotive engines: 4-cylinder passenger cars, V6 engines, some compact V8s and light diesel engines. It also works for large motorcycle heads, small tractors and generators. The limitation is very large engines like high-displacement V8s, heavy trucks or industrial machines that need longer rulers.

The measurement ruler checks surface flatness (if it's warped), while the square measures perpendicularity between surfaces (right angles). The RT-800 ruler is placed over the cylinder head to detect waves or warping with feeler gauges. The square checks if side faces are perpendicular to the gasket surface. They are complementary tools - both necessary for complete inspection.

Place the ruler over the clean cylinder head surface in different positions: longitudinal, transverse and diagonal. Use feeler gauges or thickness gauges to measure clearance between ruler and head. The ground surface of the RT-800 in GG-25 cast iron ensures precise reference. Clearances above manufacturer specifications indicate need for resurfacing the part.

A GG-25 cast iron ruler like the RT-800 lasts decades with proper use. Keep always clean, dry and protected against drops. Store in vibration-free location and apply light oil against rust. Avoid scratching the ground surface - always use over clean workbench. Perform annual calibration comparing with known standard to ensure continuous precision in the shop.