Valve Springs: Single or Double

[Diehard Ram]

I was looking at valve springs the other day, and saw several different one's.
Most are single. But i saw one that was double. Any advantage to a double over a single spring. All were rated at #110.

 

[DISTURBED]

Control and dampening

 

[Diehard Ram]

So, two is better than one! LOL! I have never heard anything bad about a single spring.

 

[DISTURBED]

Single spring at hi rpm resonates where a dual spring won't as bad. Have you ever seen the vids on YouTube of the hi rpm springs? Pretty cool in slow motion

 

[Diehard Ram]

No i have not. Looks like i should do some searching.

 

[matty169]

Try this.....

No i have not. Looks like i should do some searching.

[ame="http://www.youtube.com/watch?v=019Jyn9oB5k"]PAC Racing Springs BEEHIVE Valve Spring Testing - YouTube[/ame]

In my opinion, the best springs made.
Performance Springs, Inc. -- specialized valve racing springs, 1000 series PSI springs, dual springs, nextel, nhra racing springs - Home

 

[Diehard Ram]

That was interesting to watch. That tells me what i need to know.

 

[TMONEYDIESEL]

Actually the video posted is showing you how a beehive spring can be just as good at controlling the valve train as a dual spring.

 

[matty169]

Correct......

Actually the video posted is showing you how a beehive spring can be just as good at controlling the valve train as a dual spring.

Correct.
Especially at the relatively low rpm range of 99% of diesel engines. Unless you have an insanely heavy valve/retainer combo and need additional pressure to control bounce/harmonics, I dont believe dual springs are needed in most diesel apps. Dual or triple springs also run hotter from friction between the springs.

 

[DISTURBED]

Correct.
Especially at the relatively low rpm range of 99% of diesel engines. Unless you have an insanely heavy valve/retainer combo and need additional pressure to control bounce/harmonics, I dont believe dual springs are needed in most diesel apps. Dual or triple springs also run hotter from friction between the springs.

Can profile and boost/drive pressure it also a factor as well

 

[matty169]

To some degree probably, but...........

Can profile and boost/drive pressure it also a factor as well

Probably to some degree but I do not know at what point duals would be necessary in these apps. On our top fuel Harley engine we actually run a triple spring that has over 1000 lbs. of open seat pressure. Our cam lobe is nearly square and opens the valve nearly instantly, holds it open WAY past what seems possible and literally slams the valve shut. The lobe is actually over square slightly.
High boost, I believe, would also require stronger valve springs in order to be able to close the valve and overcome boost pressure.