Cal Grinding, Inc. Escanaba, Michigan
Custom Remanufactured Diesel Engine Valves
Engine Valve Guide Reamer - Custom Reamers

Our reamers are made with a +/- 0.0001 in. tolerance on the O.D. diameter and a +/- 0.0002 in. tolerance on the pilot diameter. Of course, the final hole size that is cut by any reamer depends on the reaming method being used in conjunction with the reamer itself. Several years ago, Cal Grinding, Inc. conducted a reamer study. The results of the reamer study showed that the reamed holes for our wet tests (reamer continuously wet) were between 0.0001 and 0.0004 in. larger than the reamer size, with an average of 0.00015 in. larger.
Our reamer design results in an extended service life (typically between 20,000 and 30,000 guides) and leaves the bore with a more consistent size down the entire length of the guide. The reamers also minimize the hour-glass effect, and help maintain the same bore size from one valve guide to the next.
Most new guides have bores with surface finishes of 60 to 80 micro in. Ra right from the box. A guide wet reamed with a CalValves reamer will typically have a surface finish of 10 to 25 micro in. Ra. A smoother guide results in less valve stem wear.
If you would like us to quote a custom reamer for you, please complete our online form, or send a detailed drawing in PDF or DWG format directly to our engineering department.
Thank you for considering CalValves reamers.