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#1
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Valve springs ????
Ok I am gathering parts to build my 440 again. The cam I've decided on is the 308 Magnum Comp Roller... 23-742-9. The recommended springs according to Comp is the 929-16. I can't believe these are the correct springs, as they seem way to weak.. I.E. 148lbs @ 1.88"installed and 432lbs @ 1.23"open. What looks like a better spring to me would be the K-Motion K-1100, which is 230lbs @1.9"installed and 555lbs at 1.25"open.... Even the K Motion springs seem a little on the light side on the open, cause this cam will only have .555" lift after the valve lash is taken out, so 1.9" - .555" would = 1.345" and that would only have 507lbs open pressure. However the comp springs would only have 387lbs open. Has anyone used this cam and what valve spring did you use....any opinions here...
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#2
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I really think on a roller cam weak springs would be detrimental. I need this thing to last this time, cause the motor was ruined last time, cause I wiped 2 Comp cams, the first I wiped during breakin, the second lasted about 3 races, and the third cam which held up fine was a Lunati, however it didn't run as well, and my bearings were toast by this time anyways. That is why I'm insistent on a roller, plus I don't like hyd. lifters (roller or flat tappet) anyways. This is about the last chance I get to play with my race truck, cause my wife wants more kiddo's, and they outrank the race truck for some reason...lol
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#3
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Why not run the Comp 938`s? 204 @ 1.9 and 516 @ 1.25? Seems strong enough for a STREET roller. Those lobes are not as agressive as a true race roller lobe. Do you have the valvetrain parts to operate at these pressures with some reliabality? Once you get in the 500`s and up, you`ll need good parts.
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#4
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By the way, isn`t the lash factored in when they give lift specs?
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#5
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The lash factor isn't usually factored in the lift specs...but I will double check this..Yes I already have the valvetrain parts ... hardened shafts, Crane Gold Rockers, Comp pushrods .080 wall 7432-16, the heads 906 factory castings can take up to .700" lift (they were built and ported by Dan Dvorak), however the flow stalls after .550" lift. Right now the springs are for the Hyd. cam... 120lbs @ 1.9" and 300lbs @ 1.4" open. the coil bind is at 1.15". I was looking at the Comp 938 springs, but was wondering if there was a reason why they recommended the 929's??? Is there anything wrong with the K-Motion springs?
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#6
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Quote:
They do recomend the 938`s on that cam. No, nothing wrong with the K-Motion spring. It looks like you`re trying to get a 600# spring for that cam, and while it won`t hurt, I don`t think they are necessary for a street roller lobe. |
#7
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Go to the valve springs listed in "RED" as they are the preimum (SP) part to use.
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#8
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rampage 82
You may wish to try a full flow oil filter with this build. This WILLl stop all remnants of failure (should this happen again)from contaminating the rest of your engine! |
#9
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Quote:
I went overkill on valve springs using the PAC Racing 1325 springs installed at #250@2.00", and about #700 open pressure. I have not used these springs before, but they were recommended. I hope they are as good as I was lead to believe, because they are pricy at $538.00 /set, not to mention the additional $400 for Ti Retainers, Machined ChroMoly locks, and spring seats. The reason I am building a new engine is I dropped a valve, possably due to old weak valve springs. |
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