camshaft ID

[44 Sebring]

Hi guys I have a Camshaft in my race tuned 350 which I wish to identify, the timing appears to be io 45 BTDC ic 55 ABDC eo 60 BBDC ec 36 ATDC is anyone familiar with this Cam. Thanks

[DewCatTea-Bob]

Hi guys I have a Camshaft in my race tuned 350 which I wish to identify, the timing appears to be io 45 BTDC ic 55 ABDC eo 60 BBDC ec 36 ATDC is anyone familiar with this Cam. Thanks

____ When you took your readings, how much clearance-space did you have set between your rocker-arms & valve-stems,, and did you take your degree-readings as soon as that clearance began to go negative, or what ?
__ Anyhow, I'm left to assume that your 350 is a narrow-case model because your resulting overlap-timing is too short to be that of either of the two other camshafts which came stock within the 350 w-c.models. _ And if actually so, then it seems you probably have the stock Sebring violet-cam, as your stated valve-timing readings are too mild to be that of a cam more suited for racing.
__ If you could provide a picture of your camshaft-lobe's profile, I could then confirm whether it's (likely) a stock Sebring/violet-cam (or not).


Duke-Cheers,
-Bob

[Jordan]

There's a collection of cam data at ducatimeccanica.com
"Cam timing for all bevel Ducati" under More Good Stuff.

Jordan

[double diamond]

The timing results you get are largely influenced by the clearance that your valves are set at when the opening/closing results were measured. I don't see any cam among the data I have that corresponds exactly with the figures you've provided. But, I've recorded that Eldert Rademaker stated opening/closing figures of 41/64 - 66/29 for a 350 W/C SCR green/white cam at 1mm valve clearance. This timing is about as close to your readings as anything in the cam timing data I have. Matt

[DewCatTea-Bob]

By: Jordan...
" There's a collection of cam data at ducatimeccanica.com "

____ Our w.site here also has such a list... http://www.motoscrubs.com/Ducati_Tech/Duc_cams.htm ,
however it does have some stated errors !
Some-time I'll have to check-out that other w.site's list and look to see if it also includes any errors as well. ---> UPDATE-> I've since looked-over that cam.data-listing,, and not only is it's hand-written data rather messy to read, it's also filled with considerable misleading errors ! <-UPDATE <-
__ Back in the late '70s (when I became a tech-adviser for the DIOC), I compiled a complete list of all Ducati camshaft-data (sourced only from just actual D.factory released printed-data), which included cam/valve-lift figures.
I've always meant to post that complete list at this w.site but, so far I have yet to get-around to doing that task.
__ I also still have my collection of most-all 250/350/450 Duke-cams, (over 12 DIFFERENT cam-models !), the only std.cams missing from my collection is the 250GT-cam and the (real) 450Mk3-cam.

____ It seems we've been left to wonder exactly what the clearance-settings were set at when he -(44 Sebring) checked his valve-timing, so I'd have to guess that his figures were taken with the recommended valve-clearance settings for normal engine-running.
And if that's the case, then the cam's clearance-ramps were included (along-with the cam's 'lift'), which then unfairly exaggerates the timing-durations. _ That being so, there's certainly no way that his camshaft is a G&W.cam (which has at least 115-degrees of v.overlap) !
The 350/violet-cam however has only 50-degrees of overlap, which logically FITS within his (likely exaggerated) stated-specs (which happen to indicate 81-degrees of overlap).
Of-course that somewhat vague clue doesn't eliminate all other cam-model possibilities,, but I've been left to assume that his camshaft is likely a stock-350 cam, and his stated-figures rule-out all other 350-cams (other than the violet-cam).


Dukaddy-DUKEs,
-Bob

[44 Sebring]

Sorry for not responding to the replying to the info posted about the origin of the camshaft in my narrow case 350 as I had to be away from home for the past week or so, the cam specs were checked @ .1mm . Subsequent to my post I have obtained a copy of the orange covered Ducati workshop manual and on page 89 I found a specification for the 350 Sebring cam timing which confirms my measurement, and DewCatTea-Bobs reply would also confirm that I have a standard violet cam. The engine has a 36mm Amal concentric Mk2 and the head has been ported and pulls very well from relativly low revs, from this I can only assume that a different cam has been fitted at some point but before I purchased the bike the sebring cam has been refitted. As an old bloke returning to racing after many years the driveability is a boon, hopefully I will get a little faster and some advice on a more race oriented cam would be usefull, as an engine strip and rebuild is planned for the long Scottish winter. Cheers Sebring 44

[DewCatTea-Bob]

" the cam specs were checked @ .1mm . "

____ Well that amount of clearance is still not enough to completely bypass all of the cam's clearance-ramp. ...
While the running-clearance is supposed to be .06mm, the clearance required for checking the valve-timing is supposed to be .2mm . _ So your resulted v.timing-figures are somewhat exaggerated.


" Ducati workshop manual and on page 89 I found a specification for the 350 Sebring cam timing which confirms my measurement, "

____ Actually, the standard Sebring figures DO-NOT "confirm" the figures you've previously stated. ...
Your stated-figures are listed at left, and the Sebring's at right ...
INtake
45 - BTDC - 20
55 - ABDC - 70
EXhaust
60 - BBDC - 50
36 - ATDC - 30
While your exhaust-figures seem to support "exaggerated" Sebring-cam valve-timing, your intake-figures, (while also possibly exaggerated), are too advanced (by 20-degrees) to be normal (and within the 5-degree tolerance-range).
So do you think you could've made some kind of error concerning your intake-readings ?
If not, then your cam ought to perform better at higher RPMs IF it were to be retarded a few degrees.


" some advice on a more race oriented cam would be usefull, "

____ In my good opinion, the Gray/M1-cam is the best factory-stock cam for racing a 350-Duke (on 'fun' road/tracks which allow good-use of 1st.gear) !
However if you wish to ring-out an extra horse, then one of the Green&White-cams would provide a slight edge but, only at TOP-RPMs !
__ Unfortunately, it seems that both the '350Mk3' & the '250F1' camshafts have been assigned that same G&W.color-code.
The 250F1-cam ([pt.# 0747.29.010], with it's 134-degrees of v.overlap) doesn't provide a great enough power-gain (available only at top-RPM) to make-up for its substantial loss of low-end power-output.
However the 350Mk3-cam (with it's 115-degrees of v.overlap) is a fairly-good compromise between the F1-cam & the M1-cam -(with it's 110-degrees of overlap).


Duke-Cheers,
DCT-Bob