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Adjustable Timing Gear


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Hey, I could not find anything on this topic in the search, but i KNOW there is info out here on it.

 

I'm looking at where i can find an adjustable timing gear for the 280z, i know they seel them just can remember where...

 

Also a technical question.

How many degrees would it change the timing by jumping a tooth on the timing gear? 5, 10 degrees?

-Ed

 

for some crazy reason my car like to run about 40 degree advance, runs great there 2.

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I suppose you could count the number of teeth on the sprocket and divide by 360 to get the degree change from one tooth. Moving the sprocket from the one to two to three holes changes it 4*, I think a whole tooth is quite a bit more.

 

http://www.arizonazcar.com has a cam sprocket for you.

 

40* advance total, I assume. You'd probably have more power with 34-36*, but depending on which distributor you have you might lose more low end than you gain top end. Here's a chart which might help you figure all that stuff out.

 

http://home.att.net/~jason510/dizzy_specs.htm

 

Jon

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40 teeth on upper gear=9 degrees cam rotation or 18 degrees crank rotation. Stock gears have 3 holes with #2 4 degrees advanced of #1 and #3 4 degrees advanced of #2.

I have bored out holes and used G.M. cam locator eccentrics. (Super Shops/Summit) to allow adjustability. I have also used the HKS multihole unit. I have seen almost no improvements over the stock gear and believe that the adjustable pully is only needed on extremely prepared motors (high compression and cam over .500 lift). After carefully "dialing in" the cam I've ended up trying the other possible holes and often ended up in a different hole than I dialed in. Waste of time and effort.

My suggestion- Use stock gear, try the 3 holes, and see which one works better for you. Save your money and buy some other performance item for the car.

If using an aftermarket cam check valve to piston clearance in all three holes as cam timing adjustment does effect clearance. On an extreme engine the multihole (8 or 9) gear may help with cam to piston clearance by allowing finer adjustments.

Yes, finely adjustable cam timing is a good thing but most street engines do not need this feature.

What is your engine build up? How wild are you going?

Hope this helps

Rick

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Nissan Motorsports recently had a selloff of a lot of inventory. They opened it up to anyone, not just dealers. I got one of the racing cam sprockets for ~$50. You might try to contact them just to see if the sale is still on and if any are available.

 

Nissan motorsports @ 1-310-538-2610

 

Fax the order to 1-310-538-1462

They only take Visa or Mastercard

 

If you want to see the whole parts list, contact me and I'll get a copy to you.

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