Is this possible ?
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Hi,
So the Ducati system won't work, but what about a pneumatic valve spring mod for the dale? Anyone have links to web info for them?
God bless...
Mark
So the Ducati system won't work, but what about a pneumatic valve spring mod for the dale? Anyone have links to web info for them?
God bless...
Mark
QUOTE (J. Delaney @ Sep 9 2007, 07:48 AM) <{POST_SNAPBACK}>
That's a WSB motor, not your average Ducati street bike engine.
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Just stroke it and dont worry about revs!Only reason they have to make them scream is class size restrictions.Agree for 450cc class Pnuematic or electric valves will happen in future for sure.But think about this.I have hundred hours at least on my Phazer sled which is a two cylinder 500cc 5v 4st.That motor runs at 11600rpm ALL THE TIME since it has a snowmobile clutch which keeps it at that rpm no matter the speed.The key is lightwieght valvetrain and Babbit bearings in rest of motor.First valve adjustment is 20,000 mi.
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Hi Steve,
What are Babbit bearings? What kind of HP is your phazer motor making?
God bless...
Mark
What are Babbit bearings? What kind of HP is your phazer motor making?
God bless...
Mark
QUOTE (cannondale27 @ Mar 2 2008, 04:00 PM) <{POST_SNAPBACK}>
Just stroke it and dont worry about revs!Only reason they have to make them scream is class size restrictions.Agree for 450cc class Pnuematic or electric valves will happen in future for sure.But think about this.I have hundred hours at least on my Phazer sled which is a two cylinder 500cc 5v 4st.That motor runs at 11600rpm ALL THE TIME since it has a snowmobile clutch which keeps it at that rpm no matter the speed.The key is lightwieght valvetrain and Babbit bearings in rest of motor.First valve adjustment is 20,000 mi.
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Hi,
I googled the pneumatic springs ans found this interesting article on Wikipedia. For what its worth...An early solution to oscillating spring mass was the mousetrap or hairpin spring [6] used on Norton Manx [7] engines. These avoided resonance but were ungainly to locate inside cylinder heads. Today, formula-one racing engines use gas springs that have no resonant parts, their working parts having an insignificant mass compared to the force of their compressed gas. These springs are expensive and short lived, therefore, offering no benefit for most motors.
Valve springs that do not resonate are progressive, wound with varying pitch or varying diameter called beehive springs[8] from their shape. The number of active coils in these springs varies during the stroke, the more closely wound coils being on the static end, becoming inactive as the spring compresses or as in the beehive spring, where the small diameter coils at the top are stiffer. Both mechanisms reduce resonance because spring force and its moving mass vary with stroke. This advance in spring design removed valve float, the initial impetus for desmodromic valve drive.
Today, desmodromic valve drive is an anachronism that, with diligence, can be made to work but at significant cost and maintenance effort. Overhead cams using flat tappets and springs offer advantages over desmodromic drive that are apparent in current automotive engines. Only those in Ducati motorcycles use desmodromic drive. Reasons for not using a desmodromic approach are increased maintenance and valve noise which can be uncomfortably loud in engines with four or more
God bless...
Mark
Ps. Pretty Wiki is not copy writed, so I think this cut and past is legal, right?
I googled the pneumatic springs ans found this interesting article on Wikipedia. For what its worth...An early solution to oscillating spring mass was the mousetrap or hairpin spring [6] used on Norton Manx [7] engines. These avoided resonance but were ungainly to locate inside cylinder heads. Today, formula-one racing engines use gas springs that have no resonant parts, their working parts having an insignificant mass compared to the force of their compressed gas. These springs are expensive and short lived, therefore, offering no benefit for most motors.
Valve springs that do not resonate are progressive, wound with varying pitch or varying diameter called beehive springs[8] from their shape. The number of active coils in these springs varies during the stroke, the more closely wound coils being on the static end, becoming inactive as the spring compresses or as in the beehive spring, where the small diameter coils at the top are stiffer. Both mechanisms reduce resonance because spring force and its moving mass vary with stroke. This advance in spring design removed valve float, the initial impetus for desmodromic valve drive.
Today, desmodromic valve drive is an anachronism that, with diligence, can be made to work but at significant cost and maintenance effort. Overhead cams using flat tappets and springs offer advantages over desmodromic drive that are apparent in current automotive engines. Only those in Ducati motorcycles use desmodromic drive. Reasons for not using a desmodromic approach are increased maintenance and valve noise which can be uncomfortably loud in engines with four or more
God bless...
Mark
Ps. Pretty Wiki is not copy writed, so I think this cut and past is legal, right?
QUOTE (m_mcgranahan @ Mar 2 2008, 11:40 PM) <{POST_SNAPBACK}>
Hi Steve,
What are Babbit bearings? What kind of HP is your phazer motor making?
God bless...
Mark
What are Babbit bearings? What kind of HP is your phazer motor making?
God bless...
Mark
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Phazer makes 80hp at crank.Babbit bearings are like are used in a car or streetbike.Sheetmetal with a coating of Babbit and another coating over that.Requires a pressurized oil system and really the moving parts are running on a film of oil.
Your last post regarding resonating springs is reason why I throw used valve springs out.Spring pressure only tells half the story.Shimming a spring that is out of spec is a waste of time.
Your last post regarding resonating springs is reason why I throw used valve springs out.Spring pressure only tells half the story.Shimming a spring that is out of spec is a waste of time.
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Hi Steve,
Hmmm, a 2cyl. 80hp dale conversion????!!!!! Wow. I was thinking I wonder if we could get those "beehive" springs made out of Ti for our motors?
BTW, have have your Ti valves and springs working for you? What will all that set me back if I go that route some day?
Thanks
God bless...
Mark
Hmmm, a 2cyl. 80hp dale conversion????!!!!! Wow. I was thinking I wonder if we could get those "beehive" springs made out of Ti for our motors?
BTW, have have your Ti valves and springs working for you? What will all that set me back if I go that route some day?
Thanks
God bless...
Mark
QUOTE (cannondale27 @ Mar 3 2008, 01:59 AM) <{POST_SNAPBACK}>
Phazer makes 80hp at crank.Babbit bearings are like are used in a car or streetbike.Sheetmetal with a coating of Babbit and another coating over that.Requires a pressurized oil system and really the moving parts are running on a film of oil.
Your last post regarding resonating springs is reason why I throw used valve springs out.Spring pressure only tells half the story.Shimming a spring that is out of spec is a waste of time.
Your last post regarding resonating springs is reason why I throw used valve springs out.Spring pressure only tells half the story.Shimming a spring that is out of spec is a waste of time.
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I need to get some time on them.Mostly just dyno and one race so far.Wayne is working on Beehive spring if I remember right should work great.
I believe that head costed me $1500 plus Timbos port work.Yes I know.Way too much but I bought it because original owner didnt pay R/D valvespring.Always wanted to try Ti valves done right also after everyone had failures with SouthBay Motors Ti setup.
I believe that head costed me $1500 plus Timbos port work.Yes I know.Way too much but I bought it because original owner didnt pay R/D valvespring.Always wanted to try Ti valves done right also after everyone had failures with SouthBay Motors Ti setup.