Setting installed height

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TT5.9mag

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What tolerance do you guys use for setting up the installed height? Comp and Lunati both say +- .020 is acceptable but I’ve got shims down to .005 so why not get them closer? I’m currently setting the installed height on my brand X speedmaster big block heads and they were all over the place as assembled from speedmaster. Glad I checked. Right now my spread is 1.890-1.906. Shooting for 1.900. Thoughts?
 
TT5.9mag said:
What tolerance do you guys use for setting up the installed height? Comp and Lunati both say +- .020 is acceptable but I’ve got shims down to .005 so why not get them closer? I’m currently setting the installed height on my brand X speedmaster big block heads and they were all over the place as assembled from speedmaster. Glad I checked. Right now my spread is 1.890-1.906. Shooting for 1.900. Thoughts?
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If you can get them that close I don't see any reason not to.
 
I’m just wondering really where I should stop. Usually I call it good at a .020 spread but my ocd is acting up. A .020 difference in installed height at my spring load is 7.4 pounds. And really the only downside of getting them closer is the time it takes.
 
Could you do an offset retainer/locks to gain some installed height on the shorter ones? Sounds like you can shim some of them pretty close to 1.900. I am one of those people that would try my best to get them all as close to my installed height as I could, so just my thought are to try and tighten the range of heights as much as I could.
 
I could but I don’t like doing that because I like to use all the same retainers and locks on one set of heads and set the height with shims. If I needed .050 across the board I would change retainers or locks but I’m down to changes in the .010-.005 range.
 
TT5.9mag said:
I could but I don’t like doing that because I like to use all the same retainers and locks on one set of heads and set the height with shims. If I needed .050 across the board I would change retainers or locks but I’m down to changes in the .010-.005 range.
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Leave the lower ones, shim the others down close to 1.900 and call it. Either that or run it now lol
 
TT5.9mag said:
What tolerance do you guys use for setting up the installed height? Comp and Lunati both say +- .020 is acceptable but I’ve got shims down to .005 so why not get them closer? I’m currently setting the installed height on my brand X speedmaster big block heads and they were all over the place as assembled from speedmaster. Glad I checked. Right now my spread is 1.890-1.906. Shooting for 1.900. Thoughts?
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I see you mentioned the variation of 7.4 lbs. I am curious if you are actually checking the spring pressure as well in that 1.90” range to know, or just setting the height and using the math to get that variation?
 
Bobzilla said:
I see you mentioned the variation of 7.4 lbs. I am curious if you are actually checking the spring pressure as well in that 1.90” range to know, or just setting the height and using the math to get that variation?
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Both. Although my spring checker is hard to read down to single digits.

turboking15 said:
I set all my springs up +- .005
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flyfish said:
If I recall correctly, I shimmed mine within 0.010.
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Thanks to both of you for chiming in.
 
AJ/FormS said:
My experience with .005s is they hammer out. If you use one, put fat boys on each side.
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I’ll be using comp cams spring locators (which the heads did not come with, just springs on aluminum) and shimming under the locators. Think they (.005 shims) will live between the head and the locators ok?
 
What I really wonder about is why they were not all the same. In 2020, it's pretty unforgivable to have machine work off that far. It was unforgivable in 1960, too, but things are supposed to get better over time.
 
If the heights are indeed “all over the place”, I’d be checking the valve job first. Has that been done? How are the stem heights?
 
gregcon said:
What I really wonder about is why they were not all the same. In 2020, it's pretty unforgivable to have machine work off that far. It was unforgivable in 1960, too, but things are supposed to get better over time.
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Agree. But, (there’s always a but) I did buy speedmaster heads and I expected to have to correct some things on them before using them after reading what others here, and elsewhere have written.
 
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moper said:
If the heights are indeed “all over the place”, I’d be checking the valve job first. Has that been done? How are the stem heights?
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The stem heights are all perfect, Surprisingly. The valve job, well I’m not a machinist so I’ll defer to you and others. I’ll say it “looks” nice.
9AE35A33-1B3F-4205-8C27-C4B419C388FD.jpeg
902257FC-2FDB-4959-BDDC-0D78DADB3595.jpeg
BBA816AD-AA70-4BF2-BB5A-9B61D7E80A8E.jpeg

If you want pics of anything else let me know.
 
MOPAROFFICIAL said:
A hair tighter is better than a hair looser..to a point.
You need to check the spring pressure .
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That’s exactly how I’ve set everything up for as long as I can remember. Measure the spring pressure, shim to within +-.020 and run it. I am a hobbyist and my tools may not measure as closely as someone with nicer stuff. I have two spring checkers and both have a scale that is hard to read down to the “pound” level. On this set I wondered how far guys really go. Your “hair” and my “hair” may be different by .010 or .020. Really that’s what my original question was. Here’s a better way of asking it, what’s the smallest spring shim you buy?
 
TT5.9mag said:
That’s exactly how I’ve set everything up for as long as I can remember. Measure the spring pressure, shim to within +-.020 and run it. I am a hobbyist and my tools may not measure as closely as someone with nicer stuff. I have two spring checkers and both have a scale that is hard to read down to the “pound” level. On this set I wondered how far guys really go. Your “hair” and my “hair” may be different by .010 or .020. Really that’s what my original question was. Here’s a better way of asking it, what’s the smallest spring shim you buy?
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.015 is the thinnest i use.
Hardened shims, especially when they're only .015-.030, copper color if using .060
 
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