.473 lift valve guide trim?

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Slantsix64

Slantsix64

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have you guys ran anything with .473 lift and had to trim the valve guides a bit?
 
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wouldn't it be much, much safer to mock up the assembly, and measure the actual clearance for your particular head, valves, keepers, retainers, guides and seals?
 
Hm yeah, but I'm just curious because I had a 474 lift prior on the same motor never had any issues but this time around I'm going to be using 340 springs or 318 springs instead of the original slant six ones
 
Slantsix64 said:
Hm yeah, but I'm just curious because I had a 474 lift prior on the same motor never had any issues but this time around I'm going to be using 340 springs or 318 springs instead of the original slant six ones
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curious is ok, but you know what's better? Measuring, and KNOWING what your clearances are. It's not that hard to do.
 
Slantsix64 said:
How do I do this? With the springs on and all that measure clearance height?
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mock it up without the springs or you can use a "checking spring" which is a super light spring that just barely puts tension on the retainer and holds up the valve enough so you can still easily depress the valve tip with your finger. You can measure the distance between valve spring seat and bottom of retainer with a telescoping gauge, or even an inside hand-caliper and then measure those in a micrometer, or in a pinch a dial caliper. You can compress the valve spring in a vise to the now measured installed height, then crank it in until you reach the full lift compressed height and check for coil bind clearance. Next you can depress the valve the specifield lift amount and measure the clearance to the guide and seal with feeler gauges stacked to fit the gap. There are other ways to do it. Be creative, but thorough. Even if it's probably
not going to be an issue, it's good practice and a good mental exercize.
 
Also, if you do have an issue just because of the retainers and locks to guide clearance, you could use the Hughes set that they use for the magnum heads that give more clearance.
I can't imagine 318 spring retainers and locks causing a clearance problem, but spring bind might.
(I see that mentioned up there)

Just mock it up like rustycowl69 said and you'll know for sure.
 
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