More pics of VVT portion of the 4.2 inline 6

Just for interests sake, here are some pictures of the Variable Valve Timing setup that the 4.2 uses. In the first picture you get a top down look at the
two cams, you can see the VVT hydraulic mechanism sitting on the front of the exhaust cam sprocket. If you look closely, you can also see the brass/copper colored VVT activating valve at the left side of the head, and the extended/enlarged camshaft bearing cap on the exhaust camshaft.
http://members.shaw.ca/ianrmac/Images/DSC00945.JPG
Here, you can see the front cap (lying off to the side) and the spool valve that activates the VVT on the exhaust camshaft. Transmission guys will recognize how this operates. The camshaft is hollow and engine oil pressure is fed to the retard/advance unit that sits on the exhaust cam sprocket and that's how they control it.
http://members.shaw.ca/ianrmac/Images/DSC00946.JPG
http://members.shaw.ca/ianrmac/Images/DSC00947.JPG
http://members.shaw.ca/ianrmac/Images/DSC00948.JPG
Ian
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Nice pictures Lan. I'l bet this system is a lot more comlicated than the one used in the 1912 Caddy. Rich B
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shiden_Kai wrote:

What happens if the VVT fails, will the cam keep turning at base timing or will the sprocket turn and the camshaft stay still.
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"Eugene" wrote

Yes, the cam will keep turning, just at some default setting, (as you say, probably base timing).
Ian
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Reminds me of this..
http://www.marinediesels.info/2_stroke_engine_parts/Other_info/MANB&W_revers ing.htm
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