Fine adjustments on cam timing

[JoeMag]

Timing up some cams and I find that each hole on the timing gear is very close to 3 degrees. I found to get reading in between that you can force the cam a little more advanced or retarded when the pin is in the hole.

Normal operation would be to force cam toward retard and then tighten bold as that's the way it would be in normal operation if there was some "slip" between the keyed gear on cam and the chain gear.

My question is if you force the cam towards advance and tighten is there enough friction force to hold it there in operation? I found if you do this you can get an "in between" setting between the 3 degrees per hole.

[Flat6pac]

I find that if you rotate the chain wheel in the chain a tooth it will give a whole new set of possibilities for settings.
I use to load the setting against the pin, then by 993 they were just using pressure of the torque to hold the setting including removing the key way from production
I did notice in the Stompski racing video he just torques on the number with the pin just in place.
Bruce

[VFR750]

I believe the answer to your question is yes, the torque creates sufficient friction, if you assemble the bolt on to dry surfaces.

Oil slathered surface is not a good idea.

I also noted the small increment, and used a small screwdriver to incrementally move the gear to get the pin in an adjacent hole.



This picture was taken after two years of operation.

You can see the three different relative positions I tried as I dialed in the timing to 4.5mm on my cam.

I had to torque that bolt three time and measure timing, but it goes very fast this way

[lvporschepilot]

I just tried JB Racing's adjustable cam gears. Get the hang on how to use them and they are amazing. Spot on accurate

[Walt Fricke]

I think I am going to spring for the JBs next time. They are by far a better mousetrap for convenience and minimizing the fuss and iteration.

[jpnovak]

Originally Posted by lvporschepilot

I just tried JB Racing's adjustable cam gears. Get the hang on how to use them and they are amazing. Spot on accurate

I will probably run these next time also.

The early cams are so easy. Grab the sprocket with tool. rotate the cam on snout with another tool. dial in your lift.

Later style cams there is no mechanism to independently turn cam relative to sprocket. I lever an allen key or screwdriver across an inner tooth and cam sprocket hole to dial in lift. With all rockers in place the spring tension will usually hold it in place. Fiddly but works fine.