Camshaft Data

[DewCatTea-Bob]

____ The below quoted-section is from (a post on page-1 of) the thread titled: "W/C Oil pump".....

A friend with many singles has reported good things about about using VeeTwo's desmo cam with H/C piston (which i have) and megaphone exhaust (which he'll lend me) in some of his bikes and I know where there is a new one of them at the right price, so despite some trepidation (particularly with the lift), in the interests of my education I'm going to give it a try. (The camshaft thread you referred me to was therefore of quite some interest).

VeeTwo desmo cam specs:

Inlet opening 54 degrees BTDC
Inlet closing 71 degrees ABDC
Exhaust opening 85 degrees BBDC
Exhaust closing 38 degrees ATDC
Lobe centres inlet 98.5
exhaust 113.5
Maximum lift inlet 12mm
exhaust 11mm
Running clearance inlet .1mm
exhaust .15mm

____ If these valve-timing specs for this cam are properly correlated with those of Ducati's given spec.figures (doubtful), then this cam is much milder (timing-wise).
What's disconcerting with these given specs, is that while the inlet closes & the exhaust opens wildly enough, the 'overlap' figures (of 54 & 38) seem relatively quite mild !
Also, if this really is a DESMO-type camshaft, then with such mild (overall) valve-timing, it's pretty-much a waste of being DESMOdromic, as such non-wild timing should make no good use of desmodromic valve control.
__ On-the-other-hand, if these given spec.figures are actually taken at later points (than Ducati does), with greater specified lash-clearance (at the point where readings are taken), then not only are these given spec.figures meaningless (with respect to Ducati's), but those overlap-figures may actually be sufficiently wild. _ However if THAT's indeed the actual case, then the "71" & "85" spec.figures should thus be way overly wild ! _ And if that's indeed the actual case with this cam, then it would be next to useless for anything other than 'all-out road-racing' !
__ Bottom-line,, IF these given spec.figures are respectful to that of Ducati's, then this cam would be an all-around fairly-good choice for a streetable Duke, (although also being a waste of being DESMOdromic, especially for 350 & 450 engines).
But if the given spec.figures are actually much wilder, (with proper respect to Ducati's), then I'd avoid this cam for anything other than constant high-RPM racing.
So, it really ought to be determined EXACTLY how those spec.figures are to be FAIRLY compared to Ducati's own !
__ I don't mean to discourage anyone from choosing this cam,, if the quality-control is as it ought to be, (most often not the case with many aftermarket cams though), then since you know of someone who's had good results with one, another one ought to be a fairly-good risk then.


Hopeful-Cheers,
-Bob

[machten]

Re the Veetwo cam, some points:

Most importantly, opening and closing figures quotes are checked at .5mm lift. Other Ducati twins opener figures I've seen are at zero (which I think is totally misleading given gas flow below 1mm opening)

Secondly, this is VeeTwo's "road/track" cam which is their compromise between tractability and performance.

I don't know how it is going to work, but it is circa $150 bucks and a few hours of spannering to test it (and then the fun of riding), and I'm more than willing to invest that in a learning experience.

We'll see what happens!

Kev

[Edit] And yes, it is a desmo cam [end edit]

[DewCatTea-Bob]

" Most importantly, opening and closing figures quotes are checked at .5mm lift. Other Ducati twins opener figures I've seen are at zero (which I think is totally misleading given gas flow below 1mm opening) "

____ I agree that the point where the lash-clearance is at zer0, is too soon to take valve-timing readings ! _ However, cylinder-pressure can be effected with just a thousandth's lift, so the FAIREST compromise at which to take valve-timing readings is at the very point where the 'clearance-ramps' lift-rate ends and the cam-lobe lift-rate begins,, which was always my understanding as being the exact point where Ducati would get their own valve-timing spec.figures from. _ And THAT point varies from one cam-lobe design to another.
__ I think -(fully realize!) that the standard 1mm lift point is way-off from fair for comparing cam spec.figures ! _ That ".5mm" is a step in the right direction but, I think .2mm is what should be used as standard ! _ (Unfortunately, I'm not the 'Dictator' of such matters.)
At least the .5mm point lets us realize that the actual timing is not too very far off from those given spec.figures ! - (I'll soon do a little math with the clearance-figures and come-up a guestimate of what [the expected clearance-ramp's effect is on whatever] the actual valve-timing figures might really be.)


" this is VeeTwo's "road/track" cam which is their compromise between tractability and performance. "

____ Well that -("tractability and performance"), sounds like something out of a sales-brochure !
With that mix, (of fairly-Wild in.close & ex.open vs. the fairly-Mild overlap), of valve-timing, it indeed seems to be a "compromise" !


" but it is circa $150 bucks "

____ That's a really good price ! - I would've expected between 250 & 500 bucks for such.
__ It'll be of much interest to learn if this aftermarket DESMO-cam has as near coinciding lash-tolerances (between opening & closing lobes) as Ducati's own !


" and I'm more than willing to invest that in a learning experience. "

____ It's actually quite great that we have someone here to do that, so I'm glad that you are going this route !
Please be sure to keep up informed of all your steps through this interesting project of yours !


Hopeful-Cheers,
-Bob

UPDATE! - I soon realized (after I got done doing this post before), that I didn't have sufficient data to actually calculate the likely spec.figures for this VeeTwo cam, so as to be fairly compared to Ducati's !
However I'm sure that my guestimate is going to be very close to what the converted figures would actually be. _ And they are:
Inlet opens 59-degrees BTDC - & - closes 76-degrees ABDC
Exhaust opens 90-degrees BBDC & closes 43-degrees ATDC
__ These adjusted figures are now more closely comparable to what they ought to be if done the same as the Ducati method.
And after seeing these adjusted figures, I then realized that this cam-timing ought to be retarded about 8-degrees !
If that doable task is done, then the resulting timing would become:
In. = 51-BTDC & 84-ABDC
Ex. = 82-BBDC & 51-ATDC
__ Now, THESE (well adjusted) spec.figures look much more familiar & desirable to me !! _ And I can therefore now actually recommend this camshaft, (if retarded the 8.6-degrees) !
If the quality of these VeeTwo cams is at least up to par, they should then be considerably more desirable than the stock Ducati DESMO-cams! _ Plus, my opinion is now changed, as this cam is actually worth being a DESMOdromic-type after-all !! - Especially in the higher-revving 250.
So now, I've gone from thinking that it's just merely an 'okay' choice, to being fully on-board with this being a great cam-choice for ya ! _ Now I'm as excited about it as you must be !
__ (I wouldn't recommend their wilder-cam though, not even for road-racing ! _ As a wilder cam would likely only produce slightly greater PEAK-power, at an unreasonable loss of low & mid-range power.)
____ I hope that when you get your hands on it, you'll then post pictures of it side-by-side with your stock DESMO-cam !


Excited-Cheers!
-Bob

[machten]

____ Well that -("tractability and performance"), sounds like something out of a sales-brochure !
With that mix, (of fairly-Wild in.close & ex.open vs. the fairly-Mild overlap), of valve-timing, it indeed seems to be a "compromise" !

The "tractability and performance" statement was my own assessment based on my reading of the cam specs rather than any marketing thing from VeeTwo. VeeTwo are now no longer trading, however Brook Henry (the original owner) recently bought back the VeeTwo farm (other than the name) on 24/12/2010 including all tooling and IP as I understand it.

" but it is circa $150 bucks "

____ That's a really good price ! - I would've expected between 250 & 500 bucks for such.

Yep! Original price US$346....but there has to be some benefit in living in the local area these things were made in! (like 12km from my home!)

If the quality of these VeeTwo cams is at least up to par,

Their quality of gear and hard chrome parts that i have purchased ove the last 5 years is excellent. They've produced bevel twin gearboxes, oil pumps, valves, guides, cams, shims, and all sorts of CNC alloy parts for years to name a few things. VeeTwo produced the Alchemy bevel twin (google it). They also produced a whole range of belt parts.

So now, I've gone from thinking that it's just merely an 'okay' choice, to being fully on-board with this being a great cam-choice for ya ! _ Now I'm as excited about it as you must be !

As you know from reading other forums, i have an interest in cams and synchronisation. My interest was spiked in these cams when I was looking at VeeTwo's twin cams. I still think they are a compromise between tractibility and top end performance, and i think they might be a pretty good attempt. As stated earlier they come recommended by someone who I think should know, but as always, the proof of the pudding...cant be confirmed without sweat, grease, oil, spanners and currency of the realm!!!

I'll keep you informed as news comes to hand. Fingers crossed!

Kev