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#1
06-22-2022, 06:34 PM
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9.44" pushrods?
I had my #64 455HO heads redone a few years ago by Dave at SDPerformance. He did guides, seats and new valves. Longer valves, set up for .560 or .56 lift. Something like that. Now I ran the engine, maybe 4000 miles since, then cam issues. I never had a pushrod checker before, and still don't. But lots of dial gauges and other things from my machine shop. Ran with Comp 9.3" pushrods, but doing the 90" mid lift method, I am coming in at 9.44, 0 preload. Crower cam saver lifters on a 041 Melling cam. Scorpion 1.65 roller rockers. Does that length, 9.4-9.5" sound right?
When doing the 90* method at half lift, I have .140" I need to make up over my present 9.3" pushrods to get the 90* Should I be also adding in .050" lifter preload to pushrod length or not? Can't really test complete stem mark right now either as no adjustable pushrod yet. Everywhere either want's a fortune, or out of stock. No build shops close by either.
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Dan Pesonen  "If it ain't broke, modify somethin till it is" |
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#2
06-22-2022, 09:26 PM
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i made a checker from a old pushrod cut in 2 used 3/16 fine threaded bolt cut down just for threaded part tapped the inside of the pushrod
i use it in conjunction with light springs from busted sprinkler heads when i lived in CA. |
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#3
06-23-2022, 03:26 AM
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Always a little nerve racking doing the math and I might get roasted for my technique.
I measure the distance from zero lash to bottoming the lifter, and that will be totally dependent on the brand of lifter. For conversation let's say we have 2-1/2 turns total from zero lash to bottom. I then leave the lifter bottomed out and get the best centered pattern I can with the adjustable pushrod. Say the test pushrod length comes out to exactly 9". I want the lifter preload to be a half turn or .025" preload (one turn being .050"). So all I have to do is add 2-1/4 turns (2-1/2 - 1/4) to the pushrod length which is another .1250" for a desired pushrod length of 9.125" and I'd probably round up to 9.150" as the available pushrod. Normally the measuring doesn't come out right in the middle of available pushrod lengths and I round to what available pushrod length is the closest.
__________________
Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon in progress. |
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