120 Cam Sprocket Position

murphus

murphus

Senior member
Location
Lost in the Midwest
Hey all. I'm in the process of swapping out the 4C cams currently fitted to my 1983 RGS for F1s. Can anyone tell me which set of sprocket mounting holes I want to use? The exhaust and intake sprockets currently fitted to the 4C cams are standard sprockets, marked S/120 on the exhaust and A/120 on the intake, with both also carrying A11, A12 and F1 markings. The exhaust sprocket has but one set of mounting holes, but the intake has two. Looking from the left side of the engine with sprocket markings visible, the intake sprocket as fitted is clocked left (counter-clockwise). I appreciate that I'll want to degree everything for best timing, but I'd like to have the correct starting point. From the little I know, I'm expecting that I'll want to mount the sprocket on the F1 cams using the second set of mounting holes. Can anyone tell me if that's correct? Or ... ? Photos attached show the intake sprocket at currently fitted to the 4C cam, viewed from left and right as fitted to the engine. Richard
 

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Hi richard - Might as well start in the same positions as on the 4/C's - then DO degree in cams and see if the other tappings would be nearer to what you want. - Regards - Phil - Ps - I'd buy the 4/c's at sensible money - can make an RGS really fly!
 
Had I bothered to remove the cam gear before making my post I would have discovered, well, what I've since discovered. And that is that whoever installed the 4C cams apparently degreed them in, as they drilled their own set of holes, hence the two sets. So, I'll start with the original holes and work from there.
Richard
 
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