Valve Spring pressure

[marshengnz]

I have added a photo of my valve spring pressure press to the Electronic album in the photos.  

We made the press as I needed a shaft/piston that did not rotate for the digital vernier. The shaft holding the piston is a D shape and fits into a D ring so it can't rotate. I radiused the shaft corners and used an Oring and it works great.

The hydraulic pump is from an old 24 volt vehicle wheelchair hoist and the controller is recycled from a electric wheelchair. It helps to have friends in the right places.

Cheers Wallace

[Jim Schneider-4]

Well, this seems to overlap some of the lines of text in your post?
Don't know why that is happening?  Seems like you could have used a
simple hand press to get the pressures needed, and still used the
digital caliper parts for travel measurement.  What is the top reading
that the fish scale will go up to?  Most of them seem to be fairly low
in lb. readings?  Neat use of inexpensive gear to get your job done!
 
Swiss
 
-----Original Message-----
From: mc-engine@... [mailto:mc-engine@...] On
Behalf Of marshengnz
Sent: Sunday, November 08, 2009 1:03 PM
To: mc-engine@...
Subject: Valve Spring pressure


 

I have added a photo of my valve spring pressure press to the Electronic
album in the photos.

We made the press as I needed a shaft/piston that did not rotate for the
digital vernier. The shaft holding the piston is a D shape and fits into
a D ring so it can't rotate. I radiused the shaft corners and used an
Oring and it works great.

The hydraulic pump is from an old 24 volt vehicle wheelchair hoist and
the controller is recycled from a electric wheelchair. It helps to have
friends in the right places.

Cheers Wallace

[marshengnz]

We needed a new press so this one does it all. It will do up to 25 tons.

The scale I have goes to 61 KG, about 125lb. More than enough for setting seat pressures. Although messy, you can change the scale by using a lever system, 2:1 3:1 etc.

I also have another recycled transducer that goes up to 2500 lb from a pallet scale. I used another fish scale electronic box and wired the 2500lb transducer into it, calibrated the scale it away it went.

Cheers Wallace

[Ava Pxia]

Is there a formula that results into a minimal spring pressure that relates
intake charge pressure, cam lift/duration, rpm,  valve weight, etc.?
Or is it a process of trial and error till you find a spring that will
manage to shut the valve on time before it gets hit?



On Mon, Nov 9, 2009 at 11:55 AM, marshengnz <helen.wallace@...>wrote:

>
>
> We needed a new press so this one does it all. It will do up to 25 tons.
>
> The scale I have goes to 61 KG, about 125lb. More than enough for setting
> seat pressures. Although messy, you can change the scale by using a lever
> system, 2:1 3:1 etc.
>
> I also have another recycled transducer that goes up to 2500 lb from a
> pallet scale. I used another fish scale electronic box and wired the 2500lb
> transducer into it, calibrated the scale it away it went.
>
> Cheers Wallace
>

[marshengnz]

There will be formulas as the Modeling people will have used them, but they are complex.

They have to take into account, valve springs, inertia, valve acceleration, valve and retainer weight and it is all related to RPM.
The calculations are complex and that's why valve simulation programs start at $5000.

The best option is to use known values.

Eg a newer Honda revs to 15000. If you are using the valves and springs in another bike with a mild cam, and only revs to 10000, you are probably ok.


Need to keep in mind that springs can resonate and that is another whole story.

See Youtube for high speed photography of valve in action

Cheers Wallace



> Is there a formula that results into a minimal spring pressure that relates
> intake charge pressure, cam lift/duration, rpm,  valve weight, etc.?

[The Hirzel Office]

I've had valve bounce and cam profile following problems with the ER-6
engine once I put in more agressive cams. Fortunately, I've had access to
the Lotus Engineering simulation software which clearly showed the problem.
It also made it very easy to redesign the valve train, i.e. spring rate and
preload to eliminate it completely. I'd hate to think how you accomplish
this without such a tool. I am sure it's possible, but being able to "see"
the effect of small changes is invaluable. I've posted a small clip on
Youtube of the "before" case showing the simulation output:
http://www.youtube.com/watch?v=ERmQoL01qzc .

 

Cheers,

Felix

 

From: mc-engine@... [mailto:mc-engine@...] On Behalf
Of marshengnz
Sent: 10 November 2009 11:13
To: mc-engine@...
Subject: Re: Valve Spring pressure

 

 

There will be formulas as the Modeling people will have used them, but they
are complex.

They have to take into account, valve springs, inertia, valve acceleration,
valve and retainer weight and it is all related to RPM.
The calculations are complex and that's why valve simulation programs start
at $5000.

The best option is to use known values.

Eg a newer Honda revs to 15000. If you are using the valves and springs in
another bike with a mild cam, and only revs to 10000, you are probably ok.

Need to keep in mind that springs can resonate and that is another whole
story.

See Youtube for high speed photography of valve in action

Cheers Wallace

> Is there a formula that results into a minimal spring pressure that
relates
> intake charge pressure, cam lift/duration, rpm, valve weight, etc.?