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Valve Spring Installed Height
So my new heads (same mfg, just ported with better valves and professional assembly) have a 0.070" different installed spring height than my previous setup. How much will the pushord lengths change? Will they necessarily? I have 1.65 ratio rockers.
70 thou is like a fuzz over 1/16"... I do plan on inking the valve stems and checking. Thoughts? |
I am not a machinist but have two things:
1. Is it a solid lifter engine? 2. I think that much difference can be taken off the top of the valve to make the clearance larger. It it is too short..... |
:eek:I am a machinist I break stuff all the time just to see how it works I know their are guys (real machinist) who specialize in setting up valve trains and they will tell you they still have to work on the aftermarket heads and it goes for all of them (manufactures).
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Also depends on whether you have bolt on shaft mounted rockers or stud mounted pozilock rockers.
.070 would hardly be noticed with a stud mounted rocker. Is the extra .070 actual stem height? Or installed height of the spring, which is a combination of all the parts? Gary |
Roller track
1 Attachment(s)
Stud mounted roller rockers, hydro cam, they look pretty good, pretty well centered. Top of stems colored with sharpie pen, pre load set, engine barred over a few times. Dizz reinstalled while doing this...
Steve H 1764 |
That's a good marking, so I would keep going with assembly.
One little thing that stands out for me is the collets seem to sit out from the retainer a bit. I would like the collet gaps to be smaller. So are the collets correct for the stem groove diameter? |
My Edelbrock heads came new with totally different springs from spec and spring heights all over the place. Had to buy new springs and shim all valve platforms for the right spring height.
Lesson learnt - don't assume new is ok just to install as is. Another point - constant valve height doesn't mean the spring height is right. |
Quote:
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Assembly
As ive gleaned from lots of reading and talking, these heads were bought absolutely bare and given to valley heads in Northridge CA to assemble. We went with Ti intake valves and Ti retainers, dual springs 180/360, and their marathon valve job. I am pretty confident that they are done right...
One thing that was a bit disturbing pulling the heads off the FRPP crate motor was the location dowels were seemingly not doing much, block engagement was minimal and they looked bent? Think some of my trouble was poorly aligned heads on the block...i drifted in new ones and the new heads clicked right in. The intake als seems to ride better when dry fitted... The thing ought to be making noise by the weekend! |
Its difficult to tell from a picture-----but some retainers and keeper combos such as that are for use with lash caps that will push on the keepers to transfer the movement against the valve retainer instead of totally just against the valve tip. This removes the force needed to open valve against these extremely high valve spring pressures from the keeper /valve stem grove in these modern small stem valves.
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The valves and pushrods are not at the same angle but close, the difference is about 20 degrees. If the geometry was correct before, the pushrods would need to be a little less than .070" longer. Check your pattern on the valve tip, probably will be OK as is.
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