Postby DewCatTea-Bob » Tue Feb 12, 2013 8:24 pm
____ Boy-O-boy, am I ever sorry that I've been stuck off-line for so long ! ... As this stuff is my second-favorite Duke-related topic, (electrical-systems being the first) !
So-thus it may take an extra-while for me to add all I wish to get included, (in this post's build-up).
____ On the subject of Ducati-manufactured camshafts made for use in 450-model springer-engines,
I unfortunately don't KNOW all I'd like to know ! _ And due to learning that Ducati didn't serve the rest of the world as they had the U.S.A., I can't be too sure of which camshaft-models were actually originally installed in ALL 450-springer models exported from Italy. _ So-thus I can't argue whether a cam found in another country's imported Duke is original-stock or not,, but with that point now understood, I'll offer what I know to be the case(s) for here within the U.S. ...
" I'm pretty sure I have a gray (grey) cam,,, "
____ Unfortunately, I believe that Ducati assigned the 'Gray' color-code to two different camshafts...
The original Gray-cam was designed for the 250 Mach-I Duke-model, thus it's designation-name is referred-to as the 'M1-cam'. ...
However, a somewhat milder version of it machined as a WideCase-version, is employed in the w-c.250Mark-3 Duke-model, (which is not to be confused with the original Mark-III 'Red' cam.model !), so-thus IT's designation-name is the 250Mark-3 cam-model.
__ While these two camshafts are considerably different, to the point that they really DESERVE differing color-codes, it's really too-bad that they seem to, (according to the parts-books), share the very-same color-code. _ This unfortunate circumstance was probably allowed because their valve-timing & lift are fairly close, (but ya can tell them apart at a glance by noting that the w-c.Gray-cam version has a notably smaller base-circle ! - [Which is a feature of all w-c.camshafts] ). _ Taking measurements of both Gray-cam.models reveals that the M1-cam has slightly higher lobe-lifts than the M3.version, (not to mention slightly wilder valve-timing).
" a 450 scrambler that I'd like to rebuild in the future. "
____ One of the 450-models came with a camshaft that's very quite similar to the Gray-cam, valve-timing-wise,, but I can't offer any other info/data on it as I've never had or even seen one of such, (and rely on another source of info about it's existence).
__ But if your 450Scrambler-model came with the same cam.model* as most, (* that being the 1968-version of the w-c.250Scr.cam), then your 450 will run considerably stronger with most any other of the wilder cam-models ! ...
__ I've done a LOT of experimenting with various Duke-cam.models in various Duke-engines, and while I've never installed a 'Mk-III' or 'M1' cam.model in a 450, I have tried a 'Mk3' cam in a 450 (which HAD had the stock std.250/450 Scr.cam originally-installed),, and it made a very notable improvement in overall power-output ! _ So I can highly-recommend that swap/change !
" The SCR has a standard scrambler cam in it now. "
____ That's fairly fair to state,, cuz as far as I know, most-all 450Scranbler-models were originally-stock with the 'White' w-c.Scrambler-cam.model (which was ACTUALLY the camshaft that was first employed within the '1968 w-c.250Scrambler' [BEFORE the 450-engine went into production !]).
__ But what's not understood by many, is that Ducati did (somewhat later) actually design a camshaft SPECIFICALLY for the 450Scrambler-model,, but so far as I-myself know, THAT cam.model was never installed by the factory, (but I've heard-tale that it was installed in some production-run or another, of the 450-engine).
" Will the grey cam work in the 450 or is it better to leave the standard cam in there? "
____ If your 450 indeed has the common/standard w-c 'White' Scrambler-cam.model, then by all means ditch that cam,, as THAT cam.model has NO-business being in any 450-engine (unless perhaps used exclusively for hill-climbing). _ Cuz that cam.model really starves/chokes a 450 from being able to sufficiently fill it's lungs (so to speak) !
__ As for trying-out your Gray/M1-cam.model in your 450, I believe that you'd then get at-LEAST the GREAT-result which I-myself discovered with the Gray/Mk3-cam.model,, however, your M1-camshaft's larger base-circle may possibly present a valve-adjustment issue for you, especially if the cyl.head's valve-seats have been over-worn or ground-down too much. _ The negative results of which could possibly be that you'd then not be able to find valve-shims which are thin enough to suit, (as they don't come any thinner than 2mm, and you may possibly end-up with only just 1.0 to .5mm or less of clearance for fitting a v.shim into).
In the past when I've run-into such an issue, I've either had to scrap the idea of fitting such a n-c.cam into my w-c.head-project, or-else grind-down the valve-shims and/or the valve-stems, (so that I could then achieve proper running valve-clearance).
It's something you'd have to check-out to be sure, but I'd guess that there's at-least a 75% chance that the M1-cam would fit-in well enough, without any such clearance concern.
" Cam measures 23/32, 23/31.45 mm "
____ That is indeed the n-c.version Gray/M1-cam.model ! _ A very DESIRABLE camshaft !
Where did you find it ?
__ If the valve-shims which are currently installed in your 450-head are fairly-over 3mm thick, then you'll probably not have any un-ordinary troubles fitting that M1-camshaft in-with it's valve-train.
" I've found a cam that has the shaft beveled down ( tapered) that is 120mm long, is this a narrow case cam? "
____ Well that seems to be a fair deduction but, all 250*/350/450 (*except the 69x66mm 250) n-c & w-c models have camshafts which are of the very-same length, of 126mm !
__ The shorter camshafts are from the 175/200 models, which have cylinder-heads that have a 'square' bolt-pattern...
The 250-models (with the 74mm-bore) needed to have their left & right bolt-pairs relocated/widened-apart (for the larger cylinder & head bore-size), and-so at that time, the camshafts got widened/(lengthened) as well ! _ Although such was not actually needed to be done, as the shorter camshafts will fit & work within the newer cyl.head design. _ I-myself have even done so but, I then prefer to fit a wider bearing into the bearing-support cap/cover.
__ If you could, it would be nice to see a picture posted of your 175/200-camshaft, (preferably placed side-by-side with your longer n-c.camshaft).
" And some springer cams that are 126 mm long, wide case 450 I presume? "
____ They all must be 250/350/450 n-c/w-c camshafts !
If you post pix of them all, I may then be able to identify their cam.models for you.
____ I WAS planning on adding more 450-cam info here in THIS post, but now I guess I'll add it later in another post.
Duke-Cheers,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob