1hr40 Posted July 15, 2009 Share Posted July 15, 2009 Sorry no picture. My car has a bit of a rough idle that I cannot smooth out. It also doesn't start to really accelerate until 2500 rpm or so. The cam has JAPAN cast into it, an H and also E30. I could not find any other markings other than a 1cm square block also cast into the camshaft. Is this a stock cam? Thank you, Michael Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted July 15, 2009 Administrators Share Posted July 15, 2009 Using your shop manual, (even the Haynes manual), and/or if you’ve done any research then you would find the lift figures for the stock cams. Armed with that information and a pair of cheapo dial or vernier calipers, you can measure the cam lobe in two places, one over the nose of the lobe and the other 90 degrees, or perpendicular to that for the base circle. Subtract the base circle measurement from the nose-of-the-lobe measurement. Now multiple that by 1.5 for the rocker ratio. Then subtract the stock valve lash clearance of .010â€-.012". Now that number should close to .393"-.413" which is the stock L-series valve lift. If your number is greater than that, chances are pretty good it is an aftermarket cam. If it less?... Quote Link to comment Share on other sites More sharing options...
1hr40 Posted July 15, 2009 Author Share Posted July 15, 2009 I will head out to get a caliper so that I can measure the lobes. I have to re adjust my valves soon. I think I made them too tight in an effort to quiet that hellish clatter. Thank you for the info! Michael Quote Link to comment Share on other sites More sharing options...
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