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Post by ron90 on Oct 6, 2011 15:27:44 GMT -5
I am trying to work on valve spring issues due to valve float.
Does anyone know where I can located specifications for "installed height", "valve lift", "coil bind height", "valve seat pressure", and "spring pressure"?
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Post by scoots27 on Oct 6, 2011 16:47:47 GMT -5
valve float? at what RPMs? are ya spinning that thing over 84 or8500?
I will meed to change them now, but I've been running my same springs for almost three years now with no issues. the installed height has been growing with every valve job.
This time it looks like---intake about .820 ext about .750ish. valve lift is .275 @0 lash.
is'nt spring press. the pressure (at installed height) of the valve on the seat? I dont know what mine are.
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Post by ron90 on Oct 6, 2011 17:09:29 GMT -5
Yes I was hitting those RPM's and loving it, except for the float.
Your installed height is supposed to remain the same even after machining. The installed height is the height of the spring in the compressed state from head to bottom of retainer. If it is too low then you shim up. If it is too high then your valve may not be opening enough. Am I missing something, or looking at this wrong?
My kart problem started with the replacement head. It had springs on it already. I don't know how old or what condition the springs are in. I intend on putting my old "cracked" head springs (not new springs) on the new head provided they spec out.
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Post by scoots27 on Oct 6, 2011 21:30:49 GMT -5
Why do you think you were floating the valves and wich one? Were there marks on top of the piston? Could it be too rich at top end? If the high speed is alittle to rich it wants to fall over itself at the higher RPM. I don't think you'll float the valve train much below 9500 RPM .
Turning the high speed in about 1\8 of a turn may just fix that but you need to reinstall the head to try it.
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Post by ron90 on Oct 7, 2011 1:07:20 GMT -5
The sounds it was making appeared to be float and metal on metal. Loss of power, etc. Issues started at Dixon, last race. Carburetor issues resolved between Dixon and PC. Thanks to BradH running great. Awesome temperature, spark plug color, response on bottom, etc. Problem loss of power and knocking at high end. I don't understand your 9,500 float reference. If you assume a float should only occur at 9,500, assumes a certain spring pressure. For example, if you have a 40 pound spring that floats at 9,500, a 20 pound spring woould float sooner because it cannot keep up with the RPMs. Notwithstanding, I found the problem and it is not in the head. (See Redding post for the rest of the story.  ) |
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