[v2junkie]

I was wondering if anybody ever played with the exhaust cam timing, I would like to retard it one tooth, but i gota no how many degrees each tooth is so i dont bash the valves, or even this can be done at all. if this is POSSIBLE this should increase top end performance.

 

[TWF]

20 degree per teeth.

 

[andyauger]

You can split the angle

If there are 18 teeth on the cam sprocket then each tooth you advance or retard is a 20 degree change, like TWF says (360 degrees / 18 teeth = 20 degrees per tooth).

If you move the chain on the crank sprocket the change would be 10 degrees per tooth, half of moving the chain on the cam sprocket. This isn't intuitive, but it's true. Moving the chain on the crank sprocket one tooth rotates the crank 1/2 the number of degrees that the cams move when you move a tooth on them.

Whether or not you gain or lose horsepower is debatable until you dyno the results. I would guess this isn't going to be a happy engine.

 

[TWF]

Re: You can split the angle

If there are 18 teeth on the cam sprocket then each tooth you advance or retard is a 20 degree change, like TWF says (360 degrees / 18 teeth = 20 degrees per tooth).

If you move the chain on the crank sprocket the change would be 10 degrees per tooth, half of moving the chain on the cam sprocket. This isn't intuitive, but it's true. Moving the chain on the crank sprocket one tooth rotates the crank 1/2 the number of degrees that the cams move when you move a tooth on them.

.

there are 36 teeth on cam sprocket.each is 10 degree.since crank rotates twice each is 20 degree.
if you move chain on crank for 1 tooth it is same,20 degree.

 

[andyauger]

OOPS, got the ratio backwards

In that case, moving the chain one tooth on the cam sprockets changes the timing 10 degrees, moving the chain on the crank sprocket moves the timing 20 degrees. I was thinking bass ackwards. The cams turn 1/2 the rate of the crank. That's what I get for trying to think without a pencil and paper in my hands.

 

[v2junkie]

i need timing specs this engine is an 05 if that helps. i think i am gona try this. it should increase overlap, whats the worst that can happen, loose power, with 10 deg i dont think i have to worry about piston to valve clearance.

 

[TWF]

Re: OOPS, got the ratio backwards

In that case, moving the chain one tooth on the cam sprockets changes the timing 10 degrees, moving the chain on the crank sprocket moves the timing 20 degrees. I was thinking bass ackwards. The cams turn 1/2 the rate of the crank. That's what I get for trying to think without a pencil and paper in my hands.

you got it right first time.for cam timing each tooth on cam sprocket is 20 degree.it is 10 if you count teeth(36) but you measure both strokes.crank makes two revolutions and cam one.
crank has 18 teeth,each 20 degree of piston travel.
now think what happens when you move chain on crank.both cams move together.at that point you better not hit starter button

 

[TWF]

i need timing specs this engine is an 05 if that helps. i think i am gona try this. it should increase overlap, whats the worst that can happen, loose power, with 10 deg i dont think i have to worry about piston to valve clearance.

you will destroy valves if you move it one tooth.
you can figure what timing is if you look at specs for opening and closing of valves.
if you go by specs listed for 03 intake is 105 and exhaust 103.
20 degree either way and you will have dancing in there.