valve springs.

[b231v6]

Well I broke another valve spring. The first time the engine had about 6500 miles on it. This time about 7500 miles. First time it was #4 exhaust now it's #6 exhaust.

My ? would be. Do roller rocker valve springs tend to brake more often then non ones?

 

[2QUIK6]

What cam and what's the lift on it? What kind/type/specs of valve springs are you runnings?
May have too much lift and the springs are binding at high rpms.

 

[b231v6]

1:55 T&D roller rockers,Schneider cam 204-214. Double valve springs 6500/6600. I can't give much more info because I can't read a cam card.

 

[2QUIK6]

As far as roller rockers tending to break them more than non, the springs don't matter whether you are using rollers or non rollers as long as the geometry is the same. Be sure that the springs you are using will not bind and can handle the lift specs for your cam, and be sure to keep in mind that the lift specs for the cam may be for 1.5 rockers, so 1.55 rockers will produce more lift.
Be sure that the rocker geometry is ok also and not coming into contact with anything.
On my truck I've got a roller cam and roller self-aligning rockers and one of the alignment disks on the rocker tip was pressing down on top of the valve retainer and not letting the rocker tip make contact with the valve stem. Had to change the valve retainer top and use a different shaped one.

 

[b231v6]

Curious, because someone told me roller valve springs have a higher spring compression. Oh well thanks.

 

[2QUIK6]

Originally posted by b231v6
Curious, because someone told me roller valve springs have a higher spring compression. Oh well thanks.

Your spring pressures should be based on what is recommended for the cam you have. Now if its a roller lifter cam, then yes, they can tolerate higher spring pressures and generally a roller cam opens and closes the valves more quickly due to the steeper grind on the cam. I'm betting that the springs are binding if you have broke two of them.
I'd post all of the info you have on the cam in another post asking what type of valve springs would be recommended for it and see what type of responses you get, and based on that and then consult a reputable racing engine rebuilder and see if they agree then change your spings to whats recommended.
Breaking a spring can be very destructive. If the retainers pop loose then you'll have 2 tiny peices of metal floating around the engine, or you could have a piston slam into the valve and do some serious damage then your talkin complete rebuild.
Be alot easier to just spend $100-$150 for the correct springs.
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You can also take one of the springs down to a machine shop and they can measure the seat pressures at different heights and tell you the max lift before binding, then compare that to your cam specs, and be sure to mention you have 1.55 rockers since that will most likely increase the advertised lift of the cam, since most cam specs are at 1.5 rockers.

 

[b231v6]

Called and ordered a few sets of springs from Schneider.
They say that is the correct spring for that cam. 290-310 lbs open and 120-130 lbs closed with 000 lash open or closed.

The one I replaced about 1500 miles earlier is o.k. Maybe It was just a bad batch of springs.

I'm getting a little better at diagnosing the problem.