Friday, April 10, 2009

Valve stem height

I made a poor man's stem height gage for Oldsmobile heads. The spec is 1.220 + - .005 for the top of the stem above the valve cover rail.
Setting the gage at 1.220. The bolt has a bevel and lines up with the center of the stem. The bevel there because the valves are not perpendicular to the cover surface.
Stem grinding on the valve grinder
Gage in use. The Olds 455 does not have an adjustable valve train so this height has to be right.


  1. I have a '72 Olds with a 455 and need a valve stem height gauge like that. Could you make me one or sell me yours? Or maybe i could make one. Did the 1.220 measurement come from an Olds factory service manual or just careful measurements on your part? thanks.


    1. Joe, I got the dimension from another GMC motorhome owner and the gage looks like what Mondello sold. Mine was made adjustable so I could get it right with out grinding or bending the gage. Mondello's gage had the angle set in the gage but what I'm doing does the same thing with careful positioning. I did meet Joe Momdello at a GMC motorhome rally, he was an owner. Mr Mondello was a character. If you make a gage I found that mine changed after a while probably from stress in the bends relaxing. Easy to recalibrate it and probably a good idea. (The dimension in use is to the center of the valve stem) Good luck!