Cam Profiles/Timing

[Anthony V]

Hey guys, new to the forum but i have been reading a while...

anyways, has anyone plotted their cam profiles to see what they actually are? look like?

i have plotted out kawi cams and got some interesting results. they dont match up to published timing numbers in the service manual. i was very careful when i did it, and did it twice. i am pretty confident in my results. at this point, i believe myself more than the service manual.

has anyone else done this and experienced similar discrepancies?

it makes it somewhat difficult to judge what the engine is actually seeing...published or my numbers. thus, harder to judge the exact changes i need to make.

U of Akron Engine Guy

[Anthony V]

Hey guys, new to the forum but i have been reading a while...

anyways, has anyone plotted their cam profiles to see what they actually are? look like?

i have plotted out kawi cams and got some interesting results. they dont match up to published timing numbers in the service manual. i was very careful when i did it, and did it twice. i am pretty confident in my results. at this point, i believe myself more than the service manual.

has anyone else done this and experienced similar discrepancies?

it makes it somewhat difficult to judge what the engine is actually seeing...published or my numbers. thus, harder to judge the exact changes i need to make.

U of Akron Engine Guy

[Kirk Feldkamp]

Did you use a cam measurement device or just measure and plot it yourself? A shop with Cam Pro Plus can save you a ton of time, and will be way more accurate than regular measurement techniques. We measured the GSXR600 cams, and they were dead on!

-Kirk

[UQ Turbo]

I didn't even look for any published figures, as turbotwig says the Cam Pro Plus is the way to go. There are so many different standards on where to start and stop measuring the duration etc. For some it is the end of the lash ramp and others it is obscure values of valve lift. I would have faith in your own results if you are confident in your measurements.

UQTurbo

[Charlie]

What was your method of measurement?

[BeaverGuy]

I did this for our kawi last year. I got nearly identical values on the intake side. The exhaust side had a longer duration but I think I made a mistake when I did them.

[Anthony V]

i did it myself. made a jig and set up a dial indicator in the mill. measured every degree of cam rotation. i am running into the same problems some of you mentioned. different methods of determining the timing numbers. who knows...

i did find that the exhaust was long too. dont think i made any mistake.

what is this cam pro plus you guys talk about? would any engine shop have it and do it for relatively cheap?

thanks

[Charlie]

How did your dial indicator interface with the camshaft though? This is very important.

[PedalOnTheRight]

To Turbotwig, Did you just find a race shop around who had the Cam Pro Plus equipment and ask them to do a profile on you cams?? I'm just wondering how to go about analyzing my cams, thanks.

[jdstuff]

Charlie,

I had a few pics of Anthony V's setup....so I'll save him the trouble of posting them:

http://gozips.uakron.edu/~jdstuff/cam_1.jpg

http://gozips.uakron.edu/~jdstuff/cam_2.jpg

[Kirk Feldkamp]

GasPedal,
I a friend of mine has a Cam Pro Plus setup... but any cam grinding shop or race engine builder should have something that can measure the cams accurately. It should only take them about a half hour to set it up, measure the cam, and put it all away. It's really not a difficult process. Just don't be demanding or annoying, and people will usually be nice enough to help you out. I wouldn't even worry if it cost you $20. Just make sure you get the data files that the measurement tool outputs!

Charlie,
Could you explain to everyone what you're getting at? I'm guessing you're talking about how the measurement interface with the cam should represent the lifter, rather than just a point contact like is shown in the pictures above?

AnthonyV,
You might want to use a live center on the non-chucked end of the cam...

-Kirk

[Anthony V]

the dial was perpendicular to the cam, straight up and down. i had the cam set up in the rotary table and orientated 90 deg from how it usually is. the cam was parallel with the mill table. i also had the cam supported vertically (and constrained horizontally) at the far end (end opposite of where the rotary table was holding it). i hope that makes sense. kinda hard to describe in words.

i have a picture if that is unclear.

[Anthony V]

Jason, looks like we were posting at the same time. http://fsae.com/groupee_common/emoticons/icon_smile.gif Thanks.

[BeaverGuy]

The reason your values are off is because you are measuring at the cam. You need to measure at the valve or bucket. The reason is that the bucket will contact the cam and start to open at a point before the dial indicator will move. I can draw a quick diagram if it still isn't clear.

[Travis Garrison]

You can translate it into bucket movement in a CAD program...I did it in AutoCAD with the cams on Viking 30...and I believe some of the WWU guys have used the kinematics modeler in ProE to convert the data a little less painfully...

[Charlie]

Sorry if I'm being cryptic but I am usually posting with a couple seconds of spare time. Also did not want to just assume someone did something wrong. But my guess was correct. I've made the same mistake.

Valve travels from cam contact with bucket, not at a single point. Make a flat end for your dial indicator that's roughly the diameter of the bucket (or a spare bucket if you've got one), that needs to be the cam-dial interface. Otherwise you'll be way off actual.

[Travis Garrison]

Charlie,

whats to stop them from taking that data, and modeling a lifter bucket in a CAD program...

[Z]

Just a small point...

Anthony isn't measuring the cam profile with a "point contact". He is measuring it with a sphere about 1/8" diameter. That makes a difference (ie. he can use a program to convert lift from the small sphere to lift of a much larger diameter sphere that represents the top of the bucket lifter).

Z

[Charlie]

That's true. In addition at the high rising rates of the cam lobe it's really hard to get the dial point in the right spot.

Technically there's nothing wrong with converting it but why add possible sources of error when you don't need to? It's honestly much quicker & easier to make the measurements with a wider dial base.

[Anthony V]

thanks for the help guys.

i might try the quick pro/e conversion to see if it works. if its still significantly different than what is claimed then im gonna re-do it with a bucket mounted.

thanks again.
later.