Originally posted by lun40119
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Valve Spring Testing 101
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There seems to be a bit of an evolution going on with valve train mass, spring rates and associated lobe design. I was really surprised when we put mine together with the A460 heads and their tall valves the first time back in early 2006 and the valve spring of choice was essentially the same as the ones I'm using now with just a bit over 215# on the seat and 650 over the nose. We we're at 230# on the seat this time, but only .830 net lift on a big block, not pushing an inch like the SBC guys are.
I'm following the build philosphy of trophy truck engines as they have to deal with harsh conditions and extended time at WOT or near to it for a 1000 miles or sometimes multiple races covering several 1000's of miles before refresh. Not the sophistication of Cup motors, but a well understood combination of bore sizes, ring packages, assessory drives etc. Each time we up the ante a bit I learn something and we go ont to the next build. I still want to keep doing all the stuff I do with the car, drags, auto-x, open course and soon standing mile, never mind the drives and driving events, so it'll never be close to what a lot folks make in terms of power etc.
Like Bob says, I'm still learning.Drag Week 2006 & 2012 - Winner Street Race Big Block Naturally Aspirated - R/U 2007 Broke DW '05 and Drag Weekend '15 Coincidence?
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Originally posted by MR P-BODY View PostDont ya think PAC might know just a little about springs
That being said.....Ill stand by my comment.
300lbs of seat pressure on a small stem Ti valve? Wow.....Last edited by lun40119; June 12, 2013, 04:23 AM.Team Clueless
1st Place SB/NA DW12
2nd Place SB/NA DW11
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Originally posted by lun40119 View PostYes they do.....I know Matt pretty well. Just ordered a set of springs from him the other day.
That being said.....Ill stand by my comment.
300lbs of seat pressure on a small stem Ti valve? Wow.....
suggested what spring.... I dont run Ti valves and run 320# on seat
and have been as high as 9600 rpm in my SB but I didnt make any
power up that high ... and I run PAC also
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Originally posted by lun40119 View PostCool.....I am telling you, with a Ti valve and a truck grind.......it won't have 300lbs seat.
but I wont run them on a so called street engine.... to pay $1000 for
the intakes and get a shorter life cycle doesnt work for my street stuff
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Originally posted by MR P-BODY View PostI would assume PAC asked what the components were before they
suggested what spring.... I dont run Ti valves and run 320# on seat
and have been as high as 9600 rpm in my SB but I didnt make any
power up that high ... and I run PAC also
Too much spring pressure can be just as bad if not worse than not enough. Think of it like cause and effect....excessive spring pressure causes excessive deflection........deflection "HAS" to be released. No way around it....it is released as loft, you will not ever "stick" the lifter to the lobe. Now you have separation, with so much spring rate you force the system back into deflection....and the cycle starts over.
I am telling you right now, because I have seen it with my own eyes.....rigid valvetrain, reduce valvetrain mass, come off spring pressure. You will find that now you have control of the valve. As you reduce deflection you increase duration at the valve, odds are, you have too much lobe for what you are trying to do.Team Clueless
1st Place SB/NA DW12
2nd Place SB/NA DW11
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Originally posted by MR P-BODY View PostI understand what your saying.. I have run Ti valves in the past...
but I wont run them on a so called street engine.... to pay $1000 for
the intakes and get a shorter life cycle doesnt work for my street stuffTeam Clueless
1st Place SB/NA DW12
2nd Place SB/NA DW11
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Yes, and Yes. The short life tells you it was not happy.2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
First to run in the .90s .80s and .70's in SBN/A
2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!
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What type of racing were you doing where you were seeing 10,000rpm? What was the combo.....just curious.
PS......spoke to a buddy also that works at an engine shop that builds truck engines.......6mm intake, 7mm exhaust..130ish/650ish spring pressures in that 2006ish era....
Then I asked about 300lbs seat on a 5/16 Ti stem.....he responded....."better have your shit together, won't tolerate much bounce or separation at all!!!"Last edited by lun40119; June 12, 2013, 06:51 AM.Team Clueless
1st Place SB/NA DW12
2nd Place SB/NA DW11
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Originally posted by lun40119 View PostWhat type of racing were you doing where you were seeing 10,000rpm? What was the combo.....just curious.
PS......spoke to a buddy also that works at an engine shop that builds truck engines.......6mm intake, 7mm exhaust..130ish/650ish spring pressures in that 2006ish era....
Then I asked about 300lbs seat on a 5/16 Ti stem.....he responded....."better have your shit together, won't tolerate much bounce or separation at all!!!"
in the mid 70s
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Drag racing is my true love.......but I am telling you right now. Us Drag Week guys, and actually all Drag Racing guys could really learn a lot from the cup/busch stuff. ESPECIALLY in the valvetrain department!!!Team Clueless
1st Place SB/NA DW12
2nd Place SB/NA DW11
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I am in Realville, Cup motor 8500/9300 for 500 miles
Drag Motor 10,000 RPM for 3 seconds of 100 passes a year for three years
That's not much cycle time at 10,000, but he Captain Cave Man cams back then and junk Valve springs where a issue. Our Cam Dynamics cam had .736 lift and broke 2 springs at least every pass.Last edited by JeffMcKC; June 12, 2013, 07:11 AM.2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
First to run in the .90s .80s and .70's in SBN/A
2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!
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