[Grand Duc]

Is there any equivalent for Ducati engine ???

This is a Chevy Roller rocker, it reduce friction of the lifter on the cam witch is steel on steel by replacing the friction point by a bearing.. I can see a HP gain and reduce wear of cam and rocker.

I did a quick search but did not find anything like this for Ducati.

http://www.enjoythedrive.com/content/?id=9722

They reduce operating friction in the engine and therefore reduce engine oil temperatures--by as much as 200 degrees in the neighborhood of the rocker arms. In turn, the engine produces more power and requires less fuel, and it will live longer, too.

 

[DucatiGuy]

Considering Harley's and other motorcycles use roller tipped rockers, I'm certain the concept is nothing new to Ducati. Why they haven't incorporated the design into their newest engines, I can't answer for sure...

 

[fairplayinc]

Doesnt the desmodromic setup cause the rocker make contact with the cam lobes at multiple locations?

If so, it may be hard to add a roller.

Someone please correct me if Im wrong.

 

[DucatiGuy]

With its current design, yes (see the above pic, notice the wide contact area beneath the tip of the rocker)... However, if a roller tip would be added, the rocker arm itself would have to be redesigned as well as possibly the cams themselves...

 

[darthvader]

DucatiGuy is right. This picture gives you a good idea why.

 

[brettc63]

I can't see the point and I'm guessing Ducati can't either otherwise they may have converted already.

I'd say the roller tip on the rocker is to reduce friction on the top of the valve because of the reasons stated by Grand Duc (Heat etc).

We have to keep in mind one word 'DESMO' - no valve spring (conventional) for the rocker to fight against and therefore much less friction at the contact points.

Effectively it is only the weight of the valve that the rocker has to move and that is only while opening. It would be hard to put a roller on the closing rocker i'm guessing. Whereas a conventionally sprung valve has the weight on the rocker 100% of the time.

I'm sure if the sums were done by ducati and there were benefits then they would have already.

Adding a roller rocker would add more reciprocating weight (not good) and also complicate manufacturing and increase cost. I guess if it ain't broke, don't fix it.

With the change to 800cc and 18,000 + rpm, i believe that the Desmo heads are finally showing their true worth (at last). Thank goodness Ducati stuck with 'odd' Desmo.

 

[Grand Duc]

Nice reply guy's !

I must agree that Desmo valves are making close to 0 pressure on the rocker.

Thanks

 

[NevadaBoy]

May be 0 pressure, but remember the rockers had the flaking problem.
I also think the roller would reduce friction and prevent the rocker to flake
NevadaBoy