Wtb: Adjustable Cam Sprocket

[oldmates260z]

Looking to set my valve timing and want to fit an adjustable sprocket to make the job easier.

 

Where are these best purchased from or does anyone have one they would like to sell?

 

Also is there anywhere about a drawing for the timing chain wedge?

[Enzo]

Oldmate,

              For a street engine the original cam sprocket will be fine. The adjustable cam sprockets won't make the job easier because you will need a dial gauge to measure valve lift. The original cam sprocket has three holes which allow for chain stretch but if the chain and guides are in good condition you can advance or retard the cam for more low down torque or top end performance. The holes are 4 degrees apart. Mind you, the difference will hardly be noticed but the engine will like it one way better than the other. I would suggest trying this instead of wasting money on adjustable cam sprockets.

              If it was a race engine or a high performance street engine, I would say the adjustable cam sprocket can be beneficial for the precise cam timing of the engine. In these circumstances you have to bear in mind the all engine components have to be working in tune with each other for maximum efficiency. Carbies, distributor, cam timing, valve timing, etc.

Hope this helps.

David.

[oldmates260z]

Thanks Dave.

 

I had the valve timing done on my U20 and it made a major change to the overall performance. This was achieved with dial gauge as you mentioned but the adjustment required was by machining the fixing bolts an only moving the sprocket and very minor amount.

 

Can this small amount of movement be achieved with the standard sprocket? (or am I missing something )

 

Thanks again Tim

Edited January 10, 2016 by oldmates260z

[Enzo]

Hi Tim,

             Standard Sprocket has 3x holes for adjustment. As mentioned I think that they are 4 degrees apart. Follow the manuals advice. Through the gear at the top you have to line up the marks to the dot. By changing to a different hole this moves the line offset from the dot to either retard or advance the cam depending on which hole you use.  First off though make sure that the crank is lined up at TDC and that the cam is correctly aligned to the mark just to make sure you are not one tooth out of alignment.

All this is explained in the manual. If you haven't got one you should get one off the internet.

David.

[600Z]

Hi Tim,

 

Years ago I had one that was re-drilled with 8 holes which allowed for a larger degree of adjustment and I found it very good. I use to set the cam then try each hole at a time until I found one that lined up or very close then check the timing again after the sprocket was fitted.

As for a wedge I never use them, just drop a long screwdriver down handle first that just fits between your timing chain and as long as you can grab it with your fingers etc to get it out who cares if the chain drops of the bottom sprocket just as long as your chain tensioner doesn't come too far out otherwise you will have to guide it back in with a long probe while pulling on the chain to push it back in (yes it works I had to do it for a mates car, the internal Spring normally stops you from loosing it too far). A wedge loads up your guides and can slip...... Just my thoughts and experience.

 

Justin