Are these still available? do they work well with fuel injection? By installiing I am not going to shorten the life of my motor dramatically am I? Has anyone had any experience with these-good or bad? would I be better off to just add a cam? I already have calmini header and exhaust with a snorkle. I am going to swap gears from stock 4.62 this winter. Currently running 31x10.5-15 with rocksteady 4.5 combo.

    Yup.RRO has them,and i have seen them elsewhere as well.

Are these still available? do they work well with fuel injection? By installiing I am not going to shorten the life of my motor dramatically am I? Has anyone had any experience with these-good or bad? would I be better off to just add a cam? I already have calmini header and exhaust with a snorkle. I am going to swap gears from stock 4.62 this winter. Currently running 31x10.5-15 with rocksteady 4.5 combo.

If you are asking all these questions, you need to better research exactly when AND why you need an adjustable cam gear.  It's not something you just do, rather it's something you need when you modify other things.

Did you install a lumpy cam?  Did you shave/deck the head or block?

Sounds like the adj cam gear is needed in specific circumstances. Maybe I would be smart to contact someone like Hawk for some guidance? Thanks

Quote from: 93trackaddict on November 25, 2007, 05:03:35 AM

Are these still available? do they work well with fuel injection? By installiing I am not going to shorten the life of my motor dramatically am I? Has anyone had any experience with these-good or bad? would I be better off to just add a cam? I already have calmini header and exhaust with a snorkle. I am going to swap gears from stock 4.62 this winter. Currently running 31x10.5-15 with rocksteady 4.5 combo.

If you are asking all these questions, you need to better research exactly when AND why you need an adjustable cam gear.  It's not something you just do, rather it's something you need when you modify other things.

Did you install a lumpy cam?  Did you shave/deck the head or block?

Do you have a stock engine? Yes, it will work with stock or modified engines but the mods or lack of will have an impact on how much adjutment you can make.

occracing.com have the gears.

Sounds like the adj cam gear is needed in specific circumstances. Maybe I would be smart to contact someone like Hawk for some guidance? Thanks

The adjustable cam gear allows you get the optimal timing for the valves. In stock form the stock spec will usually be about right. manufacturing differences in pulleys, belt lengths etc.. may mean that the cam is not set exactly when the dots are lined up. Any gains here are likely to be very small. It is possible to advance or retard the cam a little to get gains either at the top end or bottom end but overall power is likely to less.
If the head is machined then the valve timing will be changed and aftermarket cams are often not accurately machined. In these cases an adjustable cam sprocket can make a reasonable difference.

There are a couple of things to keep in mind for those considering this mod and it is worthwhile considering. Get it dialled in on a dyno and make sure that the ignition timing is adjusted as well. Just because somebody said that they could change the cam timing by "x" amount on their engine dosen't mean the same will work for yours. I had a different profile cam in mine compared to stock and you need to consider what is happening to the valves when you change the cam timing. Different engines will have different limits and there can be different amounts of advance or retard used and results gained between 2v and 4v cylinder heads. If the head has been shaved then the valves are closer to the pistons. There is also potentially more to be gained with dohc heads as you can time the cams individually. Using an endoscope in the bore to make sure that the valves aren't going to hit the pistons is not a bad idea either.

What I do like about using adjustable cam gears is the fact that you can get quite nice gains in power/torque at a more suited rpm. Basically what you are doing is taking the existing power/torque curves and shifting them further up or down the rpm range.I have added a pic of the stock 1.6 16v power and torque curves. The black is the original and the red shows the power curve moved lower in the rev range by about 500rpm when then the cam timing has been advanced. You can see the blue line shows that when the engine originally made 2500rpm the engine was developing just over 40kW but with the advance added now at 2500rpm it is making over 50kW or an increase in the order of 25%. Not too bad considering the engine has had no mods apart from the cam timing adjustment.

What I do like about using adjustable cam gears is the fact that you can get quite nice gains in power/torque at a more suited rpm. Basically what you are doing is taking the existing power/torque curves and shifting them further up or down the rpm range.I have added a pic of the stock 1.6 16v power and torque curves. The black is the original and the red shows the power curve moved lower in the rev range by about 500rpm when then the cam timing has been advanced. You can see the blue line shows that when the engine originally made 2500rpm the engine was developing just over 40kW but with the advance added now at 2500rpm it is making over 50kW or an increase in the order of 25%. Not too bad considering the engine has had no mods apart from the cam timing adjustment.

That doesn't look like an actual dyno graph  . Modifying the cam timing alters the slope of the torque curve. When you set the timing up for more bottom end torque you get less top end torque. Because bhp = (torque*rpm)/n you loose top end bhp as well as moving it down the rev range.

That is just a Suzuki supplied power and torque graph that I used to show the simplified effect of shifting the power curve. I did not alter the torque curve to match but you are correct in what you say. The beauty for us in our application is that we would normally prefer to have more power and torque earlier in the rev range and a bit of a drop off at high rpm is a compromise that I think would be acceptable to most.

For those that are interested in a cheap option for the 8v engine do a search on here about advancing the cam gear by shifting the belt one tooth.