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| nicskitz |
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Just a quick question
Can the valve springs found on the SVO Y303 alloy heads handle a cam upgrade? By looking at the stock ones fitted to it atm, they are only a single spring with what looks to be a flater spring/dampener on the iner-side. Seeing the T2 goin by crow specs had a 455thou lift cam with 1.7:1 assuming around 490thou lift or so with that ratio rocker, can they handle much larger then that with out a spring/retainer change?
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| xr8ute |
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If they are the original springs, then they are the "gt40" spring kit. You can find the specs in the Ford Racing Parts catalogue.
They are still a pretty mild spring. |
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| XR9UTE |
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I ran them on my 351 nic...no worries with the .545" Lift that resulted from 1.7 rockers on that mild comp cam.
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| nicskitz |
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Ahh excellent, cheers
That was around the lift i was thinking of goin any way,
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| gogetta |
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but u have to know the spring pressures on the seat on over the nose...its not just about avoiiding coil bind
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| nicskitz |
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well i cant check that unless the heads get pulled back off.
but more concerned about it snapping a spring, or just valve float and slapping the piston due to the valve spring not having enough pressure on it
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| XR9UTE |
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Actually you can check that with the heads still on.
My cam had a pretty extreme ramp and coupled with 1.7's it means pretty high loads on the springs. |
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| nicskitz |
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How would you go about testing this? i would say stock springs form what ive heard have something around the 100lb of pressure and doubles give you at least 120lb? this sound correct?
Also prob wont be running a crane now, was thinking of goin on of the crow roller jobs, either of the two, one has .505" lift and the other has .538", the last one will a little over kill using the 1.7, and the heads will proberly already be maxed out to there flow limit any way
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| XR9UTE |
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Take a couple of springs off while the heads are still on. You can do it either with compressed air or by feeding a piece of rubber tube into the cylinder through the spark plug hole with the piston near TDC and use an on-engine valve spring compressor. I think you'll be fine with those cams you suggested though. The springs give around 130 on the seat.
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| nicskitz |
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Thanks Pete
Are good ill just leave them at that then, and see how it goes 
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