Vortec L31 cylinder head
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(→Valve springs, retainers and locks: clean up; add text, image) |
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The stock springs are not suited for high performance use or for lifts above about 0.420" using stock retainers. There are several replacements for the stock springs, among the best is the beehive spring and retainer combination from Comp Cams, originally designed for the LS engine series. | The stock springs are not suited for high performance use or for lifts above about 0.420" using stock retainers. There are several replacements for the stock springs, among the best is the beehive spring and retainer combination from Comp Cams, originally designed for the LS engine series. | ||
*'''[http://www.compcams.com/WhatsNew/NewsDetails.aspx?ListHistoryID=164462240 p/n 26915]'''- 105 pounds at 1.8" installed height; open pressure 293 lbs. at 1.2"; coil bind at 1.100"; spring rate 313 lbs./in.; bottom OD 1.290" | *'''[http://www.compcams.com/WhatsNew/NewsDetails.aspx?ListHistoryID=164462240 p/n 26915]'''- 105 pounds at 1.8" installed height; open pressure 293 lbs. at 1.2"; coil bind at 1.100"; spring rate 313 lbs./in.; bottom OD 1.290" | ||
| − | *'''[http://www.compcams.com/WhatsNew/NewsDetails.aspx?ListHistoryID=1166393320 p/n 26918]'''- 125 pounds at 1.8" installed height; open pressure 367 pounds at 1.15"; coil bind 1.100"; spring rate 372 lbs./in.; bottom OD 1.310" | + | *'''[http://www.compcams.com/WhatsNew/NewsDetails.aspx?ListHistoryID=1166393320 p/n 26918]'''- 125 pounds at 1.8" installed height; open pressure 367 pounds at 1.15"; coil bind 1.100"; spring rate 372 lbs./in.; '''bottom OD 1.310"''' (requires the spring pocket be opened up using Comp Cams tool p/n 4721 so there's no binding) |
| − | {{Note1}}The p/n26918 springs were updated, | + | {{Note1}}The p/n26918 springs were updated, check w/Comp Cams to be sure the specs are current. |
*'''[http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=26981-16&Category_Code= p/n 26981]'''- 110 pounds at 1.70" installed height; open pressure 292 lbs. at 1.175"; coil bind 1.115"; spring rate 347 lb./in.; bottom OD 1.240" | *'''[http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=26981-16&Category_Code= p/n 26981]'''- 110 pounds at 1.70" installed height; open pressure 292 lbs. at 1.175"; coil bind 1.115"; spring rate 347 lb./in.; bottom OD 1.240" | ||
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**Seat pressure: 125 lbs | **Seat pressure: 125 lbs | ||
**Open pressure: 340 lbs @ 0.500" lift | **Open pressure: 340 lbs @ 0.500" lift | ||
| − | ** Retainer p/n 23652 | + | **Retainer p/n 23652 |
{{Note1}} K Motion K-700 springs have been reported by one member of Hotrodders,com to be breakage prone. Another member (this writer) has had several sets of 1.25" OD single springs with damper break the dampers on a 0.480" net lift hydraulic cam SBC application. Whether these problems were transient or ongoing remains to be seen. If these springs are being considered, research them first. | {{Note1}} K Motion K-700 springs have been reported by one member of Hotrodders,com to be breakage prone. Another member (this writer) has had several sets of 1.25" OD single springs with damper break the dampers on a 0.480" net lift hydraulic cam SBC application. Whether these problems were transient or ongoing remains to be seen. If these springs are being considered, research them first. | ||
===Locks=== | ===Locks=== | ||
| − | + | {{Note1}}On Vortec and other heads using self aligning rocker arms, using a +0.050" lock can cause interference between the rocker tip and the locks/retainer. Rocker contacting the locks/retainer has been encountered using a combination of c/n 906 Vortec heads, Comp Pro Magnum rockers p/n 1317, Comp retainer p/n 787, Comp spring p/n 26918, and the +0.050" locks. | |
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| + | The engine builder must mock up the assembly and check the clearance closely. In the case there's insufficient clearance, there are a few options: | ||
| + | *Use non self aligning rocker arms. Requires guide plates be installed. | ||
| + | *Use longer valves | ||
| + | *Use a different spring/retainer combo that uses a standard lock | ||
| + | *If just the locks are hitting the rocker, using a shorter (lash cap compatible) lock like the Edelbrock p/n 9615 may help. This 7 degree lock is 0.050" lower than a regular lock. | ||
| + | *{{!}}Use extreme caution if making the spring seat any deeper. | ||
| + | |||
| + | A tool to help determine the installed height using different retainers and/or locks is the Howards Cams p/n 92010, shown immediately below: | ||
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| + | [[File:Ret height92010.jpg]] | ||
===Spring seat=== | ===Spring seat=== | ||
| − | Use reduced hex head bolts or 12 point fasteners to give more clearance if a larger seat like for a 1.44" OD spring is used. Use caution if making the seat larger, there have been a few warnings about cracks developing on heads with enlarged seats. Do not make the spring seat deeper. If more installed height is required, get it from a different retainer, locks, or a longer valve stem. | + | Use reduced hex head bolts or 12 point fasteners to give more clearance if a larger seat like for a 1.44" OD spring is used. Use caution if making the seat larger, there have been a few warnings about cracks developing on heads with enlarged seats. Do not make the spring seat deeper. If more installed height is required, get it from a different retainer, locks, or a longer valve stem. |
==Valve guide boss== | ==Valve guide boss== | ||
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