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Author Topic:   valve spring installed height
posted May 15, 2003 03:58 PM
I am setting up a set of 882 chevy 400 heads with Manley budget performance valves. i am trying to put the valve springs on but do not know how to check my installed height. I have the micrometer on with the retainers and locks but dont understand the numbers it doesnt seem like a normal micromter heres the pic. my installed height is supposed to be 1.7"

how accurate does the height need to be? can it be 1.75"?

[This message has been edited by Kramer (edited May 15, 2003).]

posted May 15, 2003 04:25 PM
s-crew the height guage down and install the retainer and valve stem locks on top of it. uns-crew the guage until it contacts the retainer and the locks are seated. read the guage and that's your set-up height. if it's 1.750 and you need it to be 1.700, use a .050 shim under the spring. to be completely accurate, you need to do this on every valve and use the correct thickness shim(s) to get the correct set-up height.

[This message has been edited by outlawstock17 (edited May 15, 2003).]

posted May 15, 2003 05:45 PM
If your using a stock diameter retainer , your height micrometer will not work . As you can tell by your picture , the retainer is down inside the second step on the height micrometer . The particular micrometer that you have is designed to take the reading with the retainer seated at the top of the micrometer . Generally stock diameter retainers will not seat on the second step , you can feel the retainer wobble around . So measuring from the top step to the second step and subtracting the difference wont be too accurate . You can take a set of dial calipers , put a retainer and keeper on the valve , pull up on the retainer and measure from the spring seat to the bottom of your retainer to get your installed height .

As for reading this micrometer , the current reading in your photo is 1.970" . The micrometer measures from 1"-2" installed height by the markings .


Hendren Racing Engines
Rutherfordton , NC

posted May 15, 2003 07:17 PM
wow! i guess i wasn't paying attention...from the picture, i didn't think the retainer was present. it's not visible....heck, i'm a ford guy and fords have bigger springs.....that guage works good for a ford...and for that matter, a chevrolet with big springs.

posted May 15, 2003 07:47 PM
I've said this before, and I'll say it again. Actually, I can't believe no one has said it yet. The whole purpose of installed height (besides coil bind) is to get a certain spring pressure. That said, the only way to get correct spring pressure is with a pressure checker. If you've already done that, than your OK. Don't trust the springs to all have the same spring pressures. It's not worth it when you lose a valve into the cylinder. Your machine shop should only charge you about $50 to set all the spring pressures for you. Money well spent, to me anyway.


posted May 15, 2003 08:12 PM
I tested the pressures all of them were close to what they were supposed to be within a few lbs.

I am thinking i might just take them to a machine shop and have it done. i was working on this engine at school and time ran out, i got the seats cut but didnt have time to do this. you can barely see in the picture but i also milled for ***** in studs and guide plates.

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