f4i lift vs timing graph

[Gaanja]

Can anyone help me out with the lift vs duration graph for the honda cbr f4i (2004 model preferably)?? i have been looking for it for a long time and have not been able to find it... It would be great if someone could provide it or tell me how i can get it...

cheers

[Gaanja]

Can anyone help me out with the lift vs duration graph for the honda cbr f4i (2004 model preferably)?? i have been looking for it for a long time and have not been able to find it... It would be great if someone could provide it or tell me how i can get it...

cheers

[exFSAE]

Well.. you could get it by measuring it..

[Wesley]

ABSURD!

[Gaanja]

@ ex Fsae: Yes we did try putting the cam on a lathe with a dial to indicate the rotation and measure the the profile with a dial indicator. The problem i faced was that it tended to go off center too often. We were looking to get readings for every degree of rotation. But this turned out to be inaccurate too as the rotation was done by hand.

I did realize later that a part of the inaccuracy in measurement was due to the absence of the bucket interface between the cam lobe and point the tool. Later we did set up a bucket interface with a spring such that it is always in contact with the cam lobe. But when the points were transferred onto the cad software the profile did not seem accurate. The ramps were not accurate. This again is probably due to the inaccuracy in the rotation.

It would be great if anyone could give suggestions to improve the existing setup.

We have also thought about a jig setup where we can mount the cam on the bearings and get accurate rotation by coupling it to a stepper motor.

We have only a couple of guys around who grind cams. It is a big hassle to get through the bureaucracy and the red tape to actually get the profiles measured by them.

I posted the request for the numbers because we are only trying to measure up the stock cams. Quite a few teams or some of the manufacturers would have the data. I just wanted to know if there was any means of getting the data as it would save a great deal of time and effort. I have read about teams getting it done by cam pro plus, web cams, comp cams and the like which hardly takes an hour. It is just that we don't have such luxuries at our disposal. Also we have spent quite a bit of time on it and time is of great essence in a competition like this...

cheers

[Ockham]

There's a type of milling fixture called a rotary table that might be the answer. Imagine a lathe head stock attached to a simple rack and pinion. Rotate a crank, and you get precise rotation, usually marked in single degrees. They bolt to Bridgeport ways, so if there's any compliance in your setup, it should be pretty easy to cut it down. Once you have the actual cam profile, I'd take another crack at modeling the cam/bucket interface in CAD. You might have to make a bunch of small, simple 2D models to show snapshots of the interface during rotation.

[Gaanja]

@ Ockham : Thanks a ton... I'll see if i can get access to one right away... I know for sure our university does not have one...

[Wesley]

Barring that, pull a sidecover and connect a degree wheel to your crank via a spacer and long bolt. Pull the valve cover, put a dial indicator on the exposed part of the cam follower and rotate the engine by hand. You'll have twice the resolution since the crank rotates twice per cam rotation.

[exFSAE]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Wesley:
Barring that, pull a sidecover and connect a degree wheel to your crank via a spacer and long bolt. Pull the valve cover, put a dial indicator on the exposed part of the cam follower and rotate the engine by hand. You'll have twice the resolution since the crank rotates twice per cam rotation. </div></BLOCKQUOTE>

This.

Measure while it's still in the engine.