Ailign Honing Engine Block
Engine Rebuiling-Performance Engine Rebuilding-Automotive Machine Shop

Engine Block Line Honing
Align Honing Sunnen CH100


Alignment Checks

The alignment of the crankshaft and camshaft bores in blocks can be checked by placing a straight edge in the bores or along the bore parting lines and using a feeler gauge to check for misalignment.

How much misalignment is too much? It depends on the engine and the application. A light duty passenger car engine is not as critical as a high revving performance engine or a hard-working diesel engine. As a rule, most passenger car and light truck engines call for .002" or less of misalignment between all the bores, and .001" or less misalignment between adjacent main bores. For performance engines, you can reduce these maximum tolerances by half or more.

Another dimension to look at is bore wear. Bore diameters should usually be within .001" of specifications to support the bearings properly, with no more than .001" out-of-roundness if the horizontal dimension is greater than the vertical dimension. 

Also check for wear on the thrust bearing surface of the main cap. If worn or damaged, this surface should also be re-machined