valve collet types

[Timmy250]

groove_shape.jpg

Hi, I need to replace my valve keepers, 250 Monza, circa '62 narrow case. My valves are as #1 in photo, but it seems that replacement parts I have been able to find have only keepers for #2. Does anyone have any thoughts or suggestions? Thanks,

Tim

[double diamond]

I've never encountered a valve like #1 in a N/C single head. #2 is typical. Does the head have coil springs or stock hairpin springs?

[Timmy250]

Hair pin springs.

[machten]

Number 1 is a Desmo valve, 2 is the type of valve you'd expect to see in a Monza. The collets (or half rings) should be readily available from all the usual sources.

Kev

[DewCatTea-Bob]

[quote= Timmy250 ...
" I need to replace my valve keepers,
My valves are as #1 in photo,
Does anyone have any thoughts or suggestions? "

_____ I'm pretty-sure I've seen valves like that odd one before,, but I'm afraid I can't agree with Kev, as the keeper-groove doesn't look quite right to me, to be an actual DESMO-valve.
Could you post pictures of the valve-keepers and the spring-ties (top & bottom views), which you got with that strange valve ? _ Cuz I not only believe that your v.keepers are considerably larger than the DESMO-type 'C-clips', but I'm also pretty-sure that the associated spring-ties are-not the same as DESMO spring-ties either. _ (And if indeed they're not, then your spring-ties wouldn't be able to hold the collet which retains the DESMO-type C-clip v.keepers anyhow !)
__ My memory of finding such unusual valves & keepers is rather faint (from the early '70s),, however as I recall, the v.keepers were-not merely 'C-clips', but rather somewhat more like the rather common regular/standard valve-keepers along-with a protruding ridge (which fits into the valve-groove). _ So whereas the flat-top of the common/std.keepers lock-against the common/std.valve's stem-recess,, in the unusual case of this uncommon valve-keeper setup, the uncommon-keepers rather rely upon their added (male) groove-RIDGE to lock-into the (female) grove of the uncommon-valves. _ And-so other than their added 'ridge',, the uncommon-keepers appear much like the common-keepers, except that their top-edges aren't flattened (as the common-keepers need to be).
As for the associated spring-ties (which the v.keepers fit into), they appear to be pretty-much the same as the common std.spring-ties,, however I'm not sure whether they're interchangeable, as the common-keepers may employ a wider taper-fit (than that of the odd-keepers).
____ My only suggestion, (if you really need replacement valve-keepers), is to acquire the common/std.type valves to go with the type of v.keepers which you can obtain.


Hopeful-Cheers,
-Bob

[Timmy250]

Bob, I believe you are correct. I'm away, but will post pics when I return.

Tim

[DewCatTea-Bob]

[quote= Timmy250 ...
" will post pics when I return. "

____ Looking forward to that, and hope you have at-least one of the uncommon valve-keepers to show us ! _ If you have both pairs,, then please take a close-up picture showing all four laid-out so that we can see each one posed at a different angle, with each exposing an opposite end and/or side.
Then hopefully I'll be certain to identify whether they are the exact-same type which I-myself have encountered (within old-250 or 200 heads).
__ Also to help reduce the number of pictures taken, please show both spring-ties posed together with one upside-down & laid at a different angle.
What's important to determine about this part (which the v.keepers fit into), is not only whether a DESMO-type, but also whether interchangeable with the spring-ties that retain the common-type v.keepers.


Hopeful-Cheers,
-Bob

[machten]

Here's a pic of the inlet valve that came out of my 250 M3D (bottom) and the new one I put in it (top). You may recall my query at the time regarding the different relative distance of the c-clip slots from the top of the valve stem.

The slot width does look a bit larger. The width of the slot on my pictured valves is about 1.3mm as best as I can measure it.

Inlet Valves.jpg2.jpg

Kev

[graeme]

How much clearance from the collet groove, fitted with a closing shim, to the lower edge of the opening shim?
Where did you buy the new valve?

Graeme

[machten]

I don't recall exactly Graeme, but there was no issue with that clearance. Best photo I have is this..The head had just been fitted with new valve seats and guides at this point. The closing shims I ran fairly loose to accommodate Ducati's rather asymmetrical camshaft opener/closer lobe grinds.

Capture2.JPG

I got the valves from Ian Gowanloch back in 2011. I've had no issues with them at all.

Kev