cam profiles, lobe angles, etc...

[A Reinke]

hey guys, we're doing some modeling in Ricardo, and we tried (and failed) at measuring the cam profile on our 2001 Suzuki GSXR 600.

has anyone else been able to get some numbers besides lift and duration from their formula engines?

some specifics like, lobe center angle would be nice.

any help is appreciated, thanks.

[A Reinke]

hey guys, we're doing some modeling in Ricardo, and we tried (and failed) at measuring the cam profile on our 2001 Suzuki GSXR 600.

has anyone else been able to get some numbers besides lift and duration from their formula engines?

some specifics like, lobe center angle would be nice.

any help is appreciated, thanks.

[Denny Trimble]

I've never done it, but how difficult is it? I'd imagine you could chuck your camshaft in a lathe, find a way to read out rotational angle (perhaps on the chuck because it's large), and set up a dial indicator to read out displacement. Then rotate in small increments and record readings.

University of Washington Formula SAE ('98, '99, '03, '04)

[Travis Garrison]

I've measured cams for our V8, fairly simple to get close...stick the cam in the A axis, and measure away...

Good measuring tools are critical though, make sure you're using a nice dial indicator...should be obvious, but wasn't to me at the time.

Travis Garrison
WWU FSAE

[Matthew]

denny-
you'd still need to determane an anchor angle - to locate the ICO in crank degrees, plus its easyer to mock up something on the engine and measure actual valve lift rather than just the cam, that way valve lash is included

-Matthew Hetler
hetl0020@umn.edu

[A Reinke]

the lathe is a good idea...

i'm still not all familiar with what numbers we need just yet. was anyone able to get some 'actual' numbers off a motorcycle engine ever?

~Adam

[Travis Garrison]

A Reinke, as I mentioned above, I've done it before, and yes I got actual numbers off a camshaft.

If you want to make a new cam, you will want to measure the cam itself, couple of reasons for this, biggest one is so you know how the factory cam ramps up to lift, esp as it takes up any backlash / clearance.

You can either measure the cam directly with a dial indicator actually contacting the lobe (risky in my book, a lot of ways to get off center) or you can simulate the bucket the cam would actually act on by placing something flat, and stable, between your cam and the dial indicator. In my case I used an electronic tool offset device (used to set offsets for our CNC machines), which turned out to be a lot less accurate than I was led to believe.

You should also make sure you're aware of how your measurement technique will effect your numbers before you get too far (measuring off the bucket will mean the number need to be tranlated before generating a cam profile, and measuring off the cam will require translation before you actually know the lift curve)

If I had it to do over again I would consider simply removing the valve and replacing it with a long rod of the same OD as the valve stem, or shimming the valve such that the valve and bucket are always in very solid contact with the cam (never let the valve seat itself). This would ensure that you were actually measuring the ramp on the cam profile as it approaches the lift curve. All you would have to do to measure it would be to build a large degree wheel that you could mount on you cam gear, and measure lift with a dial indicator...then setup some method of turning the cam by hand. No fancy equipment needed and you should end up with very accurate numbers

Travis Garrison
WWU FSAE

[karter]

The diameter of the follower/cup needs to be accounted for as the contact line moves accross it. Best way to measure a cam without a fixture is on the engine, just put the appropriate shim umder the cup for zero valve lash and use a degree wheel on the crank. Any decent speed shop will have a degree wheel.

[A Reinke]

Travis, thank you. we aren't making a new cam, we just would like some of the numbers to put into the computer software for an accurate model.

[turboteener]

I chucked the cam up in a rotary table and measured degrees in relation to lift and made an excell graph and chart that would give me the numbers that I needed. You just measure in a 360 degree rotation and then translate the lift back to zero.

University Of Alabama in Huntsville

FSAE car #124