High rpm miss

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OK. Went out tonight and double checked everything. Yesterday was wham bam quick check pattern. Today I got more precise. Cleaned every thing and rechecked pattern. This time I set lash and used a magic marker to mark the valves. The dymek was chipping off. Lash wasn't perfect because I just used the edge of the valve. Lashed at .022. This helped. The way I see it is it shortens duration and raises the rocker another .015 or so before it makes contact. Anyway I'm getting about .033 now and about .110 to .115 from the edge of the valve with the 7.1 pushrods. Take it this all being measured with a magnifying glass and a dial caliper. Having crisp lines to measure helps. New springs coming with taller coil bind height. Should be .094 from bind. Thinking about going with what I have. SO close.
 
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aaronk785 said:
OK. Went out tonight and double checked everything. Yesterday was wham bam quick check pattern. Today I got more precise. Cleaned every thing and rechecked pattern. This time I set lash and used a magic marker to mark the valves. The dymek was chipping off. Lash wasn't perfect because I just used the edge of the valve. Lashed at .022. This helped. The way I see it is it shortens duration and raises the rocker another .015 or so before it makes contact. Anyway I'm getting about .033 now and about .110 to .115 from the edge of the valve with the 7.1 pushrods. Take it this all being measured with a magnifying glass and a dial caliper. Having crisp lines to measure helps. New springs coming with taller coil bind height. Should be .094 from bind. Thinking about going with what I have. SO close.
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You could try it with the 7.100" pushrods, and it might clear up the valve float, even without changing the springs. That's the cheapest test you can do. But, I'm thinking it could probably use another .025-.050" of pushrod length to get where it should be.
 
aaronk785 said:
OK. Went out tonight and double checked everything. Yesterday was wham bam quick check pattern. Today I got more precise. Cleaned every thing and rechecked pattern. This time I set lash and used a magic marker to mark the valves. The dymek was chipping off. Lash wasn't perfect because I just used the edge of the valve. Lashed at .022. This helped. The way I see it is it shortens duration and raises the rocker another .015 or so before it makes contact. Anyway I'm getting about .033 now and about .110 to .115 from the edge of the valve with the 7.1 pushrods. Take it this all being measured with a magnifying glass and a dial caliper. Having crisp lines to measure helps. New springs coming with taller coil bind height. Should be .094 from bind. Thinking about going with what I have. SO close.
Click to expand...

I always try and stay near the .050 between coils rule of thumb...years ago, maybe iir even said by smokey, or was it that circle track article from the 90's... you get the maximum performance and less harmonics iirr pushing that spring for all its worth.
I've played with springs, 'while on a least resistance faze' and let me tell ya... if you're going to play with Springs do it on a motor with tons valve to piston clearance. You need to have the right spring rate and as much Seat pressure as you can 'reasonably speaking' stand ...and not destroy anything.
I tried few diff comp sets and found vsi's dug into and shiny retainers..lol... couldn't hardly feel it , but it was happening and pure luck I didnt eat one... well, that and the mile of valve clearance I had in that 340. Good springs, k motion. Look at a set if those is my advice.
 
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MOPAROFFICIAL said:
you get ..... less harmonics iirr pushing that spring for all its worth.
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Which makes sense.... the biggest thing to fight the vibrations set up within the springs due to rapid length changes is the stiffness of the spring itself. It moves the resonant frequency up higher and further away from the rates of the impulses being put into them.
 
I wanna say; "Gee,all I did was shim mine up some,adjust my rocker arms, cut my pushrods to fit at .5 turn preload, and let 'er buck". But some people might get the wrong impression of me. lol. However, that is just about how it went together.The KB107s seem to have generous pockets.
 
Springs will be here tomorrow. So I'll give it a try and let you know how things turn out. Thanks for all your help everyone. Learned a lot over the last few days. When I go through my 340 this winter I'll have to double check my valvetrain and correct things. This will help me a lot on future builds. Thanks again. Going to get some 7.150 pushrods also.
 
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took car out last night. Ran great to 7000 rpm. Shift point is 6600 so I think were fine. Thanks again for all the help. Never had this problem before, guess I've been lucky but I usually don't mess with stud rocker systems, and now I know how to set one up properly. Thanks all.
 
aaronk785 said:
took car out last night. Ran great to 7000 rpm. Shift point is 6600 so I think were fine. Thanks again for all the help. Never had this problem before, guess I've been lucky but I usually don't mess with stud rocker systems, and now I know how to set one up properly. Thanks all.
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Glad it is working right! Make sure you pay just as much attention to the shaft systems. They are just approached from a different perspective.
 
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