Editing Valve spring tech

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[[File:Spring clearance diagram1.jpg|thumb|upright=3|Valve spring clearances. Seal to retainer may be less in some cases]] 
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==Overview==
This article will show how to set up the valve spring installed height to prevent coil bind and check/correct the clearance at the valve guide boss/seal and the valve spring retainer. Only simple hand tools will be required so that most anyone can do this at their home garage.

==You will need:==
#A 6" to 8" length of small diameter welding rod or clothes hanger wire
#Wire cutters 
#Caliper or 0"-2" micrometer 
#Feeler gauge pack
#Bench-mounted vise
#A buddy on hand to help
#Bench grinder or hand-held file
#Needle-nose pliers
 
==Procedure==
*Using the installed height of the outer spring given with the springs, cut a piece of welding rod or clothes hanger wire to that length. Round both ends of the wire on a grinder, or with a hand-held file. 

*Install a valve with retainer and keepers. Use a heavy grease to hold the keepers in place. Pull on the retainer while twisting clockwise and counter-clockwise slightly to seat the assembly, pressing down on the valve face with your other hand to prevent the valve from rotating. 

*Hold the wire with needle-nose pliers and position it between the outer spring pocket and outer step on the retainer. 

*Have a buddy use a feeler gauge to measure the gap between the wire and the retainer. This will tell you the shim thickness you'll need to achieve the correct installed height. Mark a single ring around one end of the wire with a felt-tip marker, to identify the wire later. 

*Cut another wire to length, so that it fits between the inner spring pocket and the inner step of the retainer. Mark two rings around one end of the wire with a felt-tip marker.

*Subtract theoretical valve lift from installed height. For simplicity, let's say the installed height is 1.700" and the theoretical valve lift is 0.500". Cut a third wire to 1.200" and mark it with three rings. 

*Place the outer spring in a vise along with whatever thickness of shims you determined you will need (within +/- 0.015" is close enough tolerances). Holding the three-ring wire with needle-nose pliers and the wire parallel with the spring in the vise jaws, compress the spring down to the length of the wire. 

*Insert a 0.010" feeler gauge blade between the spring coils at 5 positions along the spring. If the feeler gauge goes in without interference at all positions, you're good to go with the outer spring.

*Measure the length of the two-ring wire with a caliper or 0-2" micrometer. Subtract theoretical valve lift. Cut the wire to this new length. Place the inner spring in the vise (no shims). Holding the two-ring wire parallel with the spring, compress the spring down to the length of the wire and repeat with feeler gauge. If it clears at all 5 positions, you're good to go with the inner spring. 

*Disassemble the retainer/keepers. Install the correct shim thickness you will use. Reassemble retainer/keepers. Holding the one-ring wire with pliers on the spring shim/shims at the outer step, open the valve until the retainer outer step contacts the wire. This will place the retainer at the full valve lift position. Verify 1/16" to 1/8" clearance between the valve guide and the bottom of the retainer. If seals are installed, you're good to go. If seals are not installed yet, allow for their height above the guide.

*If the clearance is insufficient, different retainers or keepers (available in +0.050" size) can be used to correct it, or you can cut the valve guide bosses to correct the issue. An alternative is to use longer valves, just remember that using longer valves will alter the installed height of the valve spring. Most valves are available with stems that are 0.050" or 0.100" longer than factory specification. Adjust your shim thickness accordingly.

==Resources==
;Crankshaft Coalition wiki articles
*[[Valve train points to check]]
*[[Adjusting hydraulic lifters]]
*[[How to prep and start a rebuilt engine]] 
*[[Identifying camshafts]]

;Hotrodders forum threads
*[http://www.hotrodders.com/forum/difference-measured-vs-calculated-coil-bind-clearance-192254.html?highlight=between+single+coil Valve spring coil bind]
*[http://www.hotrodders.com/forum/rocker-arm-199353.html Valvetrain geometry]

[[Category:Engine]]
[[Category:Camshaft]]