38 replies to this topic

[OzOAP]

Conical valve springs are the future. I have been running them on Minis for over a year now, High seat poundage, low poundage at full lift, steel top caps weighing 5g.
Have a look at www.facebook.com/ozoap

[Cooperman]

Sounds good.

[hhhh]

Conical valve springs are the future. I have been running them on Minis for over a year now, High seat poundage, low poundage at full lift, steel top caps weighing 5g.
Have a look at www.facebook.com/ozoap

I hate Facebook. I couldn't find the the conical springs at the link. A search on "spring" yielded nothing. Who supplies them? Thanks.

[nicklouse]

Ian does. PM him.

[OzOAP]

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Edited by OzOAP, 14 June 2018 - 08:40 PM.

[grizzler73]

Interesting, what is the theory behind them please?

[hhhh]

They're self-damping because of the oval wire cross-section shape and changing radius (so inners are completely superfluous, except for breakage backup). You get higher lift without bind, and because the radius is smaller at the top, you end up with much lighter retainers,

[grizzler73]

They sound good! What sort of rev range would they be an advantage for? I will probably not go much over 7000 rpm.

Edited by grizzler73, 15 June 2018 - 09:33 AM.

[hhhh]

It all depends on the particulars of the design. I didn't know anyone made them for Minis, that's why I asked about supply. They may not be an advantage at extreme levels of lift and RPM, but that's not typical with Minis anyway.

[nicklouse]

Well Oz has been fitting them for at least 2 years that I know of.

[OzOAP]

I do two different types. They are limited to 0.400 lift.
On the 998 Mini 7 we rev to 9500.
At installed height they give a seat poundage of 75lb, same as most aftermarket springs, but at full lift(for Mini 7) they are 130lb where as other springs are 180. Less pushrod flex = more lift and controlled timing.
Some race series think they offer such an advantage, they have tried to ban them!

Edited by OzOAP, 15 June 2018 - 05:23 PM.

[grizzler73]

So a sort of rising rate in reverse! The lift is more reliable so therefore at top revs your timing is more reliable. I looked at my regs and valves springs are free. I think I might get a set...

[Racer_Pete]

I would change the 1.5 rockers to either the standard ones or get the 1.3:1 rockers, imo 1.5 are overkill with a 296 cam, what does it Idle at and when does power come in?

[OzOAP]

Interesting feedback on conical springs on PM.
Interest from Australia and Canada, two countries that have strong links to V8s where the conical spring development came from. They obviously know the benefits.

[dotmatrix]

I would change the 1.5 rockers to either the standard ones or get the 1.3:1 rockers, imo 1.5 are overkill with a 296 cam, what does it Idle at and when does power come in?

in my engine, wide open throttle can be used from about 3200 rpm. idle isn't great. when hot it idles at about 12-1500rpm. it wont idle much lower than that.