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Cam and valvetrain longevity....??? low duration high lift...

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Old 10-04-2016 | 05:28 PM
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mine to

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Old 10-04-2016 | 05:29 PM
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Must have had some valves not closing all the way also. Could explain the overly rich looking chambers, down on power, chamber cc's? etc. Would be nice to know what installed height was suppose to be in comparison to what is shown.

Last edited by getrdunn; 10-04-2016 at 05:48 PM.
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Old 10-04-2016 | 05:47 PM
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Originally Posted by getrdunn
Am I seeing measurements correctly? So .040 difference? l
you are,,but remember this too.the springs seats in the head could also be all over the place.plus the seat on the valve could be in a different height also,,stacking the tolerances.

key is to put the head in seat cutter machine and index all the seats.see where they are.when I cut them,there dead nutz on.
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Old 10-04-2016 | 05:52 PM
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Originally Posted by sutphen 30
you are,,but remember this too.the springs seats in the head could also be all over the place.plus the seat on the valve could be in a different height also,,stacking the tolerances.

key is to put the head in seat cutter machine and index all the seats.see where they are.when I cut them,there dead nutz on.

So go by the furthest one in and cut all to same depth with new seats? Time to bake your heads in the wife's oven rather than a roast. Get lucky at 475 they might just fall out.
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Old 10-04-2016 | 05:59 PM
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Reminds me of the shop that replaced the seats and rebuilt my old heads. Install heights all over the place. However, those were 15 year old castings, that been thru a few hands. If the install heights varied that much on a new set of heads that never been cut, I would think that is , well, not so great. At the very least, even if the seat height varies that much, or like sutphen said, the casting itself having different heights of the spring perch, you would think that someone would go thru them, record all install heights with the retainer and locator installed, and shim accordingly, so at least, all the springs have equal pressures. .040 variance, is alot!

Any good shop worth its weight, would blueprint a set of heads so to speak, and check each valve. Not check one valve, throw 16 springs in there, and call it good.
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Old 10-04-2016 | 06:04 PM
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I thought this was all checked when the lifter stuck ?? before it went back together.......spring issues ect.
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Old 10-04-2016 | 06:05 PM
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Old 10-04-2016 | 06:12 PM
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Originally Posted by MILD THUNDER

Any good shop worth its weight, would blueprint a set of heads so to speak, and check each valve. Not check one valve, throw 16 springs in there, and call it good.
better check all the heights,,plus check all the springs.
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Old 10-04-2016 | 06:13 PM
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Originally Posted by getrdunn
So go by the furthest one in and cut all to same depth with new seats? Time to bake your heads in the wife's oven rather than a roast. Get lucky at 475 they might just fall out.
easier to run a tig torch around them and shrink them.then they fall out.
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Old 10-04-2016 | 06:15 PM
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Originally Posted by sutphen 30
better check all the heights,,plus check all the springs.
For sure. On mine, we checked all 32 springs. Sure enough, we found 1 spring out of spec.
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