Valve spring height
08-21-2008, 10:06 PM
#1
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Location: Brighton, TN
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Valve spring height
Ok i am at that point in my cam install where i am checking my spring height and i dont understand how to read the mic. Here is a pic can someone tell me what this means? http://gh94z28.diinoweb.com/files/CI08%20057.jpg
I am installing 26918 valve springs and 4705 spring seats and Locks 614-16 and retainers 795-16. I just want to make sure i get this right. Thanks in advance
I am installing 26918 valve springs and 4705 spring seats and Locks 614-16 and retainers 795-16. I just want to make sure i get this right. Thanks in advance
08-21-2008, 10:18 PM
#2
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I would say the mic is reading 1.905" but it will be reading .150" too high since that will be the difference between the top of the mic and the shoulder the retainer is sitting on. This makes the reading 1.755". You will need to check the distance from the top of the mic to the first shoulder to be sure. Just take the reading and subtract the shoulder distance and that is your installed height. Remember to give the top of the valve stem a rap with the handle of a screwdriver or other item that is softer than steel and readjust the mic to seat the locks.
08-21-2008, 10:20 PM
#3
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Search for the thread that was begun on 8/4/08 on this topic. The title is:
<Summit Valve Spring Height Micrometer>
You are experiencing the same problem in getting a measurement because the retainer is not resting on the top edge of the mic. That thread explains how to deal with this problem. If you have questions after reading the thread, ask away! This is a manageable problem once you understand what's going on.
Good luck,
c
<Summit Valve Spring Height Micrometer>
You are experiencing the same problem in getting a measurement because the retainer is not resting on the top edge of the mic. That thread explains how to deal with this problem. If you have questions after reading the thread, ask away! This is a manageable problem once you understand what's going on.
Good luck,
c
08-21-2008, 10:58 PM
#4
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I would say the mic is reading 1.905" but it will be reading .150" too high since that will be the difference between the top of the mic and the shoulder the retainer is sitting on. This makes the reading 1.755". You will need to check the distance from the top of the mic to the first shoulder to be sure. Just take the reading and subtract the shoulder distance and that is your installed height. Remember to give the top of the valve stem a rap with the handle of a screwdriver or other item that is softer than steel and readjust the mic to seat the locks.
08-22-2008, 03:45 AM
#6
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Join Date: Jan 2007
Posts: 275
I would say the mic is reading 1.905" but it will be reading .150" too high since that will be the difference between the top of the mic and the shoulder the retainer is sitting on. This makes the reading 1.755". You will need to check the distance from the top of the mic to the first shoulder to be sure. Just take the reading and subtract the shoulder distance and that is your installed height. Remember to give the top of the valve stem a rap with the handle of a screwdriver or other item that is softer than steel and readjust the mic to seat the locks.
It was exactly the same for me when installing pac1218s. Just measure like he ^ said and you should have no problem.
08-22-2008, 09:25 AM
#9
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Since the mic is only marked to 1.800" the final number has to be extrapolated. One full turn past 1.800" would be 1.900" plus the .005" past the zero mark. While it would be better to have a mic that registered all the way out, this is an acceptable practice at this point. Don't forget to subtract the depth of the recess in the top of the mic from the indicated number. On my mic that depth is .150". Yours could be different. This is one of those occasions where .005" isn't a big deal. Shims only come in .015", .030", and .060" anyway. Compared to some other measuring situations inside a motor, this is not ever going to be a highly precision-dependent process. Use the 1.905", subtract the depth of the recess and that number will be the installed height of the spring. Put the spring on a tester, pull it down to that height, and read the pressure. Shim as necessary to get the final pressure that you want.
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