4* advance sprocket on Chevy SB

Date 10-25-2006 15:34

Most cams already have 4 deg of advance ground into them from the factory.There is no magic in advancing the cam, its all just valve events. Buy a cam that has the power curve where you want it and install it straight up.

By dmilesdot (**)

Date 10-26-2006 14:40

There is a process called "degreeing the cam" that you should do when you install a new cam to make sure that the cam that you have opens and closes where it is supposed to. To make small degree adjustments you place eccentric "buttons" on the alignment pin and that will move the large sprocket small amount to bring the cam into spec.

By rwiegel Date 04-28-2007 06:29

In my mind advancing the cam moves all cam events (overlap open close--) forward.
The cam specs have a lot to do with settings most aftermarket energy or rv cams
have some added advance. Two advantages why I like to advance cam timing.
1 the earler the intake closes the more pressure (cilinder pressure) is created.
2 as the chain wears and stretches the valve timing stays ahead of specs.
Back in the olden days we built a 460 ford and advanced to cam 8+
The thing had so much cylinder pressure it was pushing presssure past
the porclen steel seal on the plugs as seen by brown streaks on the plugs white
part..

By DaveBoyer (*****)

Date 04-29-2007 04:25

Cam timing changes where in the RPM range the engine breathes most effectively. That being said, when You go to aftermarket parts, You really need to check and sometimes change the cam timing to get the results You want. Retarding the cam timing moves the torque peak higher in the RPM range, at the expense of low end torque. Advancing the cam timing increases low RPM torque at the expense of high RPM torque. The optimum setup varries the cam timing with the RPM. Honda has a device that extends cam duration [holds the valves open longer] as RPM increases on some engines, I am not sure who else may be using similar technology. I don't think I would overly advance cam timing in anticipation of timing chain wear.

By aevald

Date 04-29-2007 16:04

Hello DaveBoyer, I believe Toyota also has a similar type of technology in their Tundras and Sequoias. I believe it was referred to as variable valve timing. When my wife bought a new Sequoia we opted to go with a last years model because it was the first year at the time for this technology. That particular motor upgrade was supposed to give an additional 45 horsepower over the same older motor. I haven't hear any pros or cons since the introduction of it. Regards, aevald

By DaveBoyer (*****)

Date 04-30-2007 07:55

I too would hesitate to buy the first year or two's production of a new ANYTHING. Some products get to the marketplace before all the kinks are worked out, and some never get resolved. VVT does have the ability to greatly flatten the torque curve providing good torque at lower RPM's as well as maintaining the torque in the higher RPM ranges where You would expect it in a high performance engine. As You probably know the torque falls off in higher rpm's because of decreased volumetric efficiency - the cilinders cant fill with fuel/air mixture. At some point the torque is decreasing at a greater rate than the RPM's are increasing, and the horsepower is reduced above this RPM, the horsepower peak.

By rwiegel Date 05-01-2007 06:46

OK lets get to the bottom of the 12 pack here Varable valve timing devices have not to do with original post .
Some engines use VVT to enhance performance (intake cam) most use VVT on exhaust in replacemet of EGR
moving exhaust valve timing to cool/dilute cylinder by RETAINING exhaust gas at various rpms all controled by the engine computer.
1-Buy a cam 2-get specs 3-degree to specs + or - to set it as it was on paper..
4-BE HAPPYthat you can sat cam as you want it. 5- cans left in 12 pack
Bottom end top end wifes car who knows. Imparss my ability to drive cars with advanced cams :)