My reasons for putting up this thread are I wanted to discuss the relative merits of deleting the ME7 CVVT in favour of vernier pulleys or some alternative cam timing method.
There are 2 basic versions of variable valve timing. Volvo uses phased timing where the position of the cam lobe is advanced or retarded relative to the crank position. so that the valves are lifted to the same extent but earlier or later in the cycle and VTEC cam shift timing where the actual lift of the valve is altered, by shifting different profiles in and out, but we'll leave that to Honda.
Ferrari use a 3D lobe that allows a continuously variable profile on the cam which moves laterally to increase or decrease the lift...
This YT vid shows much of the ideas involved.
From 1999 onwards Volvo introduced CVVT on ME7 engines on the exhaust cam. To be honest I wasn't sure how it worked - GIYF - I found an article in PDF format.
Having sat here & thought about it a while - does the CVVT in ME7 actually help at higher RPM - or would it just be better to blank it off & use a cam which is optimised for the tune/map on a given car?Originally Posted by Volvo
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