Factory Lash/Cam

General engine tech -- Drag Racing to Circle Track

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Curveit
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Factory Lash/Cam

Post by Curveit »

I was wondering how the Chevrolet factory set the valve lash on flat tappet Hyd cams, over the years. And while I'm asking, how did they go about breaking-in Cams ?
dannobee
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Re: Factory Lash/Cam

Post by dannobee »

By robots now (or at the end of the standard SBC run, before LS's). If you want to know how it worked, it keyed off of the top of the rocker ball and the top of the stud. If you want to know how to set up hydraulic lifters so that you don't have to readjust, use the end of your dial caliper and measure from the top of the stud to the top edge of the rocker nut. The measurement should be 0.190". This is assuming all factory parts.

The engines were fired on natural gas at the factory for a quick break in and timing adjustment. The cams were pretty mild and didn't go flat as often as a modern race cam.
gn69z28
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Re: Factory Lash/Cam

Post by gn69z28 »

I've seen a video on youtube about Ford's engine plants from the 60s and 70s and they have engines hanging on chains and the guy would start them up and rev the snot out of them.
Curveit
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Re: Factory Lash/Cam

Post by Curveit »

I seemed to have heard of running on Natural Gas to break them in, but I never really thought much about how they set lash on Hyd and Solid cams back in the older days. I know doing them like me would take an army of people to keep up with an assembly line.
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