Motoscrubs.com

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

44 Sebring wrote: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

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

Jordan

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

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

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

" 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