measuring & adjusting valve spring install height - Team Camaro Tech
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post #1 of 4 (permalink) Old Mar 16th, 03, 03:34 PM Thread Starter
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Join Date: May 2001
Location: Antigua & Barbuda
Posts: 260

I need some assistance with my sportsman II heads - they are the 64 cc 2.02/1.60 straight plug version - bought complete and set up in house by PAW -

my original springs are like 2.3..." free length -PAW knock off up to .600 lift.

I bought a used swapped out roller cam - the springs were thrown in and a handwritten note saying install at 1.900 for the cam - a Lunati special purpose roller #50157 - 248* int&exh - .555" int&exh

I measured these springs - they are about 2.1.." free length - no specs but the diameter fits where my existing 1.437" springs were installed - they are probably about 1.5" dia. or just a bit less

I decided to try one and the height including retainer is 1.87" / 1.88" - I previously measured the retainer and got about .075" to .08" - so I subtracted that and got an install height of 1.79" - 1.8"

If this sounds right so far, how can I get the springs to 1.900 to suit the cam - or do I have to condemn these springs, and if so why???

If I have to buy other springs what information do you give in order to get them to fit your heads?

T.K.-85 Camaro-383ci/AFR 210 CNCport-65cc/ProSystem750DP/SRP 7cc dome/Motown int./Comp.S roller 268/275-108*-.720"/.700"@1.6/Big Shot plate/TH-350/8in. conv./4.71 Ford 9in/1.75 super comp/10pt. cage/29.5x10.5x15
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post #2 of 4 (permalink) Old Mar 16th, 03, 08:26 PM
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Join Date: Feb 2002
Location: Williamstown,PA
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The installed height is measured from the spring seat to the bottom of the retainer. There is a tool you can buy that you put in place of the spring. You then turn the dial until the valve seats and then you read the measurement. You can also install the retainer and locks on the valve without the spring and measure the distance between the spring seat and the bottom of the retainer with a machinist's ruler and convert 32's or 64's to decimal. 1-58/64 is 1.90625". If the distance measured is less than you need you have to cut down the spring seats.

'69 RS Camaro 355 5-speed 4.11
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post #3 of 4 (permalink) Old Mar 17th, 03, 02:08 AM
Join Date: Apr 2000
Posts: 21,341

I took a 2.25" long finishing nail and used a pair of "dikes" to trim it to an approximate length and then filed it to the exact length I needed measuring with my dial calipers.

I then just mocked up one of my valves and inserted it between the retainer and head. You can use shims of various thicknesses to shorten this length if too long or offset retainers of different installed heights as well as .050" taller locating keepers to get very close to where you need to go.

My BB needed the standard .015" pocket protector hard shims so that is why I mentioned shims, plus I am also using the .050" taller keepers.

Hope this helps. pdq67

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post #4 of 4 (permalink) Old Mar 17th, 03, 08:35 AM
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Location: Kentwood, MI
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If you use the small (factory size) 7* keepers most pockets will have your installed height around 1.75". You can increase that to about 1.80 with +.050 locks (designed for this purpose). The larger heavy duty 11* keepers make roughly the same installed height as the small +.050 locks, so typically you are looking at about 1.80" tall. The 11* locks are also available in a +.050 variety which puts you up to about 1.85".

All pockets are a little different so the example I gave above is kind of generic. There are two ways to increase installed height if you can't get what you need by changing locks/retainers and adding shims. 1) cut the pockets deeper like PDQ said. 2) get valves with longer stems.

Whatever you do don't just install the springs too short --- that will increase the seat and open pressure to a level that can potentially damage the cam (wiped lobe)

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