Classic 2CV Racing Club

Classic 2CV Racing Club Ltd Forum => Technical => Topic started by: Andrew Bull on September 23, 2008, 09:39:14

Title: Cam Profile
Post by: Andrew Bull on September 23, 2008, 09:39:14
This is the Results of the Cam Profile Measurements I have taken from a standard Cam and a Club Cam.  Both Used.

THIS IS MEASURED WITH THE CAMSHAFT IN THE ENGINE, AND CAN BE DONE AT THE TRACK, WITH THE ENGINE IN THE CAR.

The net Effect of the club Cam is approximatly 1mm extra cam lift. Thus multiplied by the rocker ratio quoted on the club cam specs on the website = 1.15mm extra valve lift. 

Method. 
Using a USB data capture device in to an Excel spreadsheet
Measure the lift with a Digital Dial Gauge from push rod or valve top cap, at pre-determined points on a degree wheel.  For this I used 5 degree increments, triggering the capture device using a Laser sensor.
Complete six Crank revolutions giving three cam revolutions.  (for accurate measurement).
The three revolutions will overlay each other again showing any measurement errors. 
The average of the three revolutions is then plotted on the graph shown in the attachment.

I have also included a baseline showing the Standard Cam. 

These are the first complete set of results I have obtained using the prototype form of the equipment and a Loaned Data Capture device and Digital Dial Gauge.  The completed working system will be developed over the off season and hopefully will be much more user friendly.  I also hope to tune the equipment to use the teeth on the flywheel rather than a degree wheel thus giving even greater accuracy of measurement, and quicker results per engine.  Some spreadsheet development will also take place for accurate record keeping. 

IN SUMMARY- THE CLUB (OR SCRUTINEER) WILL* HAVE THE ABILITY TO MEASURE CAM SHAFTS FOR LIFT AND PROFILE AT ANY TIME AND WILL NOT NEED TO REMOVE IT FROM THE ENGINE.


* Subject to approval from the technical committee and spend on the Data capture device and Digital Dial gauge being authorised.
Title: Re: Cam Profile
Post by: Pete Sparrow on September 27, 2008, 19:54:32
Andrew,
This is excellent work. This is why we love you.
I am most impressed that you managed to make the graph look like a pair of breasts. I can see no reason why any male member of the club (and may be some females) wouldn't want to see their cam profile on a graph like that, in fact, can i have my engine done first please! (does the shape change with the age of the cam like in reall life?)
Now I really can't wait until next season, the club goes from strengh to strengh  ;)
Title: Re: Cam Profile
Post by: Andrew Bull on September 29, 2008, 10:34:10
In theory pete yes it will. 

As the cam gets older the peaks will get lower, just as your analogy suggests.  Maybe we can find other similar areas on the car that show these feminine tendancies to sink / get lower / droop with age. 

I suppose for equality, we ought to say that valve springs are like married men.  Exhibiting the male tendancy to get weaker with age.  Tyres could aslo be compared to men of ageing years.  As they get older, they get more bald!!!!!

Any one got any more feminine / masculine relationships they may have noticed?????

Dare we say valves are like women?  Very tempremental...........likely to snap at any time.......... Now I am walking that fine line between being funny and getting in to trouble!  oops.






Title: Re: Cam Profile
Post by: Derek Coghill on September 29, 2008, 14:21:57
You could say that valves can be a bit like Anne Boleyn.
Title: Re: Cam Profile
Post by: Andrew Bull on September 29, 2008, 17:14:19
So we could draw the conclusion that if your a larger driver your valves will lose thier heads.  (you know Henry was a fattie).  I wonder if this is where the phrase could be re-written.
" if you can keep your head whilst all those around are losing theirs ...., maybe you'll win!!!!"

Title: Re: Cam Profile
Post by: Pete Sparrow on October 06, 2008, 19:15:36
What a bizzare post this has turned into. I tried to lighten the subject by getting breasts (every close to my heart) into a technical discussion on camshafts (bet no one else thought about doing it) and we get from that onto some sort of royal history. That's the last time I bother with you lot. ???
Title: Re: Cam Profile
Post by: Roo on November 14, 2009, 15:10:57
Is this sort of thing common?
(http://photos-f.ak.fbcdn.net/hphotos-ak-snc3/hs111.snc3/15856_179939181860_564731860_3514188_2586598_n.jpg)
Title: Re: Cam Profile
Post by: Paul Robertson on November 14, 2009, 15:40:47
 yep,even on standard cams.caused by sticking followers,not bedding cam in properly.
Title: Re: Cam Profile
Post by: Sean on November 18, 2009, 21:41:03
....and cam re grinders "takin it too far" and going thru the hardening?

Sean