Adjustable CAM PULLEY explained

What To Look For When Buying Adjustable Cam Pulley

Stock cam pulleys cannot be adjusted. In order to tune/adjust your power or torque band, you must purchase an aftermarket adjustable cam pulleys. Choose the ones that are:

1. light so that they don't add valvetrain mass (anodized billet aluminum)

2. have good cam gear bolts to hold down the cam gears to prevent them from slipping after you've torqued them down (usually these have more than 3 bolts but there's a balance between having too many bolts so that it becomes an inconvenience during tuning and not enough to prevent slipping. I'll put up with inconvenience since slip prevention is a priority.). The cam gear should be rigid or surface-hardened enough to prevent the bolt from sinking into the cam gear surface.

3. have etched-on, clearly readable, easy to understand, highly accurate markings. Painted on markings are easily worn off. if the 0 degree mark is not TDC what good is the cam gear? Some cam gears makers have not double-checked (quality control) their TDC markings against the stock TDC marks and degree the cams after their cam gears have been installed to see if the 0 mark is truly TDC, so be cautious on install and check.

Make sure that INTAKE 0 degree and EXHAUST 0 degree markings on those cam gears were indeed set at TDC?

On a tuning session on the street or at the strip, I suggest that you do the cam gear tuning by going with a friend in the passenger seat with a stopwatch , if you don't have a datalogger that records speed and elapsed time. Do some wide open throttle acceleration runs at the 1/4 mile strip on a test & tune day.

The point here is that , for each cam gear setting, do your timing over the exact same stretch of road and over the same exact distance. Have your friend time how long it takes you to go from say 30 mph to 90 mph. Do 2 runs for every setting. You want an objective measure ,like an acceleration time, to tell you if the setting is good for your particular engine. Acceration is the change in speed over the change in time. You want a higher number if the cam gear setting is good. A change of 1 tenth of a second or more consistently is good.

Don't rely on the butt dyno. It's only sensitive to changes in the early part of the rpm range.

DO NOT COPYCAT SOMEONE ELSE CAM PULLEY SETTING
Each person's engine will have a different optimal cam gear setting for it. Just because someone has the exact same model Integra and parts as you, does not necessarily mean that their engine and yours behave identically. Variations in performance can occur simply from minor differences in assembly at the factory, engine break-in procedures (if any) by the owner, and owner maintenance.

I would go 2 camshaft degrees at a time starting with the intake cam, since it also determines the reference baseline ignition timing as well (connected to the distributor) . Do 2 runs per setting over the same track distance.

When you stop seeing an improvement in the elapsed time in between your 2 set mph points, then go back to the best setting.


DoN'T FORGET TO RESET YOUR IGNITIoN TIMING BACK TO YOUR INITIAL SETTING USING AN IGNITIoN TIMING LIGHT AFTER THE INTAKE CAM GEAR HAS BEEN CHANGED AND YOU ARE DoNE CAM GEAR TUNING.


WARNING: If you advance the intake cam gear and retard the exhaust cam gear too far, you risk piston to valve contact. Remember 1 cam gear degree = 2 crankshaft degrees and so you exceed 8-10 cam gear degree change at your own peril, unless you have precisely degreed your cams and know exactly how many degrees max. advance/retard you have to play with.