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Shiming Valve springs

2K views 1 reply 2 participants last post by  dgcantrellsr 
#1 ·
Hey you guys,
Yesterday while trial assy of my heads for cc'ing, I was checking my valve spring height with a valve spring mic and adding shims to get the correct "installed height". I was using the mic kind of like a screw jack by twisting it hard back and forth several times after it had take up all the slack between the head and retainer to make sure the locks were seated and recording the measurement.
Well, I was measuring the 5th valves height when I decided to make sure the locks and retainers were seated by smacking the valve stem with a plastic hammer with the mic fully extended. I didn't think it would be a good thing to do to the mic, but I needed to know the locks were fully seated.
Lo and behold, the mic could be extended another .020" after smacking the stem about 3 times. After removing the mic, I set it to the same reading and measured it with a caliper, to see if I had damaged it with the hammer blows, and it was basically the same reading.
So apparently, just extending the mic isn't enough force to seat the locks into the retainers fully, if a few smacks with the hammer will seat them further.
Something tells me I should'nt be subjecting the mic to blows with the plastic hammer! As far as the springs already installed, I'm going to remove and re-shim them as needed. I know the locks would seat into the retainers further than they are now after being in a running engine in short order, causing me to lose some seat pressure, or worse.
My question is how else can I seat the locks with the mic in place without having the mic extended, or is it ok to smack it around a little?
ssmonty
 
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#2 ·
Well in my opinion the mike is not meant to be abused like that, if .020 is making you parinoid just add it to the reading you get when the mike is tight.
Close counts in horse shoes, hand grenades and setting up spring height. Given the size of spring shims it's nearly impossible to set them up exact anyway.



ssmonty said:
Hey you guys,
Yesterday while trial assy of my heads for cc'ing, I was checking my valve spring height with a valve spring mic and adding shims to get the correct "installed height". I was using the mic kind of like a screw jack by twisting it hard back and forth several times after it had take up all the slack between the head and retainer to make sure the locks were seated and recording the measurement.
Well, I was measuring the 5th valves height when I decided to make sure the locks and retainers were seated by smacking the valve stem with a plastic hammer with the mic fully extended. I didn't think it would be a good thing to do to the mic, but I needed to know the locks were fully seated.
Lo and behold, the mic could be extended another .020" after smacking the stem about 3 times. After removing the mic, I set it to the same reading and measured it with a caliper, to see if I had damaged it with the hammer blows, and it was basically the same reading.
So apparently, just extending the mic isn't enough force to seat the locks into the retainers fully, if a few smacks with the hammer will seat them further.
Something tells me I should'nt be subjecting the mic to blows with the plastic hammer! As far as the springs already installed, I'm going to remove and re-shim them as needed. I know the locks would seat into the retainers further than they are now after being in a running engine in short order, causing me to lose some seat pressure, or worse.
My question is how else can I seat the locks with the mic in place without having the mic extended, or is it ok to smack it around a little?
ssmonty
 
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