The camshafts need to be located fully in the cam bearings during cam timing. The factory installed camshaft hold down caps are intended to locate the camshafts for the factory method of cam timing with the camshaft alignment pins. The factory camshaft hold down caps have about .010" bearing clearance. That allows the camshafts to float in the bearings during the cam timing process that is described in the article. This will negatively effect the accuracy of the adjustments as outlined in the article.

To properly hold the cams in the bearings it is necessary to use camshaft hold down caps. These are tight clearance bearing caps. They are used to hold the camshafts tightly in the bearings as the cam cover would.

The caps are available from Jeal Enterprises. Contact Bill Kirchhofer at 502-921-1046 (KY) for information about purchasing the camshaft hold down caps.

I have noticed that on some cylinder heads the hold down caps will fit too tight on the camshaft bearings. If the engine is difficult to turn after tightening down the caps they should be loosened slightly until the excess friction diminishes.