Vortec L31 cylinder head

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(→Valve springs, retainers and locks: clean up; add text, image)

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(minor clean up)

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Line 153:

{{!}} It's unknown at this time why there's a discrepancy in the exhaust flow of the Vortec heads between the two tables.

−

==Upgrading and ~~Compatibility~~==

+

==Upgrading and compatibility==

−

The L31 Vortec head ~~will bolt directly onto Gen 1 small block Chevrolets. They will also obviously work~~ on ~~L31 engines (sometimes referred to as Gen1+). They are not compatible~~ with ~~Gen2 (~~LT1 or LT4) engines. They are also not compatible with any of the current LS engines.

+

The L31 Vortec head can be used on any SBC engine from 1955 through the end of Vortec production, with the exception of the Gen 2 LT1/LT4 engines used in some vehicles between 1992-'97. They are also not compatible with any of the current LS engines.

There are some inherent costs associated in swapping from 1995-back heads to the L31 Vortec heads. Here is a list of items to be purchased and/or labor associated with the upgrade:

Line 160:

* Springs if the cam has a valve lift over about 0.420"

* Center bolt style valve covers if the heads used previously were perimeter style

−

~~[[File:Vortec valve-rocker.jpg|thumb|right|300px|Self aligning stamped steel rockers]]~~

+

** Note: [http://www.crankshaftcoalition.com/wiki/Vortec_L31_cylinder_head#Small_port_Vortec_head_p.2Fn_25534351_.28bare.29_and_p.2Fn_25534421_.28assembled.29 GMPP small and large port Vortec heads] and other aftermarket Vortec heads accept either perimeter or center bolt valve covers[[File:Vortec valve-rocker.jpg|thumb|right|300px|Self aligning stamped steel rockers]]

−

** Note: [http://www.crankshaftcoalition.com/wiki/Vortec_L31_cylinder_head#Small_port_Vortec_head_p.2Fn_25534351_.28bare.29_and_p.2Fn_25534421_.28assembled.29 GMPP small and large port Vortec heads] and other aftermarket Vortec heads accept either perimeter or center bolt valve covers

+

*Self aligning rocker arms

* Valve cover gaskets

Line 185:

Line 184:

The stock Vortec valve springs are single wound without a damper and are 1.250" diameter. The damping is done by the spring ID (.880") being a close fit to the guide boss OD (0.845"); this damps the spring without the added cost of an inner flat wound damper seen on the Gen 1 SBC throughout its production. If you have aftermarket springs designed for the earlier heads, you must remove the inner damper because the damper ID will be too small to fit over the guide boss without it being cut smaller. If the boss is cut smaller, a damper should be used.

−

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=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)

+

*'''[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"'''

−

~~{{Note1}}~~The p/~~n26918~~ springs were updated, check w/Comp Cams to be sure ~~the~~ specs are current.

+

{{Note1}}The p/n 26918 springs requires the spring pocket be opened up using Comp Cams tool p/n 4721 or equivalent so there's no binding. The p/n 26918 springs were updated, check w/Comp Cams to be sure these 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"

Line 206:

Line 205:

===Other springs===

−

The following valve springs are single w/either no damper or damper removed. They fit the stock seat and retainer unless otherwise noted.

+

The following valve springs are single w/either no damper or damper removed. They fit the stock seat, guide boss, seal, and retainer unless otherwise noted.

*Comp p/n 981

Line 225:

Line 224:

**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 (p/n unknown) break the dampers on a 0.480" net lift hydraulic cam SBC application. Whether these problems were transient or ongoing is unknown. If these springs are being considered, research them first.

===Locks===

Line 242:

Line 241:

===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 caution if making the seat larger, there have been a few warnings about cracks developing on heads with enlarged seats. Maximum spring seat diameter is 1.44". 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. 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==

Line 250:

Line 249:

[[File:VORTEC GUIDE BOSS MODIFIED.jpg|thumb|250px|Before (right) and after]]

−

In order to fit one of the commonly available smaller diameter positive type valve stem oil seals, the tops of the guide boss needs to be turned down. To fit springs with a smaller ID like ~~doubles~~ or ~~those with~~ a damper, the guide boss needs to be modified by shortening and decreasing the OD of the boss.

+

In order to fit one of the commonly available smaller diameter positive type valve stem oil seals, the tops of the guide boss needs to be turned down. To fit springs with a smaller ID like double springs or springs that use a damper, the guide boss needs to be modified by shortening and decreasing the OD of the boss.

Line 375:

Line 374:

==Recommended spark plugs==

The exact heat range depends on several factors. This is a guide that will get you in the ballpark. Carefully assess the heat range before settling on a plug for your particular combination.

−

* AC Delco ~~Rapid Fire~~ Spark Plugs R44LTS

+

* AC Delco Rapidfire Spark Plugs R44LTS

−

* AC Delco ~~Rapid Fire~~ Spark Plugs MR43LTS

+

* AC Delco Rapidfire Spark Plugs MR43LTS

* AC Delco Rapidfire No 3 Spark Plug

−

* ~~ACCEL~~ P526S U-Groove ~~“SHORTY”~~ Double Platinum (approximately 3/16″ shorter than AC R44LTS)

+

* Accel P526S U-Groove “shorty” Double Platinum (approximately 3/16″ shorter than AC R44LTS)

−

* ~~ACCEL~~ 516

+

* Accel 516

* Autolite 26

* Autolite 104

Line 632:

Line 631:

Example: 12-235-2 Comp Cam Extreme 4 X 4, flat tappet cam, lift I .447”, E .462”, duration @ .050” 210 I, 218 E.

−

Strong low end and mid range torque. Excellent cam for ~~R.V.,~~ and pickups when changing to the Vortec heads.

+

Strong low end and mid range torque. Excellent cam for RV's and pickups when changing to the Vortec heads.

Note: Valve spring change is required with this cam.</td>

Line 682:

Line 681:

−

Holley ~~Custom, Cast Aluminum, Ball~~-~~Milled Top, Valve Covers~~. The rigid 1-piece aluminum castings combine strength and light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise.

+

Holley custom cast aluminum valve covers with ball-milled top. The rigid 1-piece aluminum castings combine strength and light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise.

</td>

Line 694:

Line 693:

−

Holley ~~Custom, Cast Aluminum, Polished Flat Top, Valve Covers~~. The rigid 1-pc aluminum castings combine strength and

+

Holley custom cast aluminum valve covers with polished flat top. The rigid 1-pc aluminum castings combine strength and light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise.

−

+

−

light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise.

+

</td>

Line 708:

Line 705:

−

MR Gasket, 1987-up SBC, center hold down, baffled. Included: 2 covers, 1 oil fill cap, 2 PCV/breather grommets.)

+

Mr Gasket, 1987-up SBC, center hold down, baffled. Included: 2 covers, 1 oil fill cap, 2 PCV/breather grommets.

</td>

Line 724:

Line 721:

−

<td class="wbg-blacktext" align="center" valign="top">Crane Cams valve spring and retainer kit. ~~(drop~~-in springs with no machine work needed)</td>

+

<td class="wbg-blacktext" align="center" valign="top">Crane Cams valve spring and retainer kit. Drop-in springs with no machine work needed.</td>

</tr>

Line 744:

Line 741:

−

<td class="wbg-blacktext" align="center" valign="top">GM Composition Head Gasket, .028” thick compressed. ~~(price is for one gasket)~~</td>

+

<td class="wbg-blacktext" align="center" valign="top">GM Composition Head Gasket, 0.028” thick compressed. </td>

</tr>

Line 752:

Line 749:

−

<td class="wbg-blacktext" align="center" valign="top">GM Composition Head Gasket, .051” thick compressed. ~~(price is for one gasket)~~</td>

+

<td class="wbg-blacktext" align="center" valign="top">GM Composition Head Gasket, 0.051” thick compressed. </td>

</tr>

Vortec L31 cylinder head

Revision as of 07:33, 16 January 2013

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@@ Line 153: / Line 153: @@
 {{!}} It's unknown at this time why there's a discrepancy in the exhaust flow of the Vortec heads between the two tables.
-==Upgrading and Compatibility==
+==Upgrading and compatibility==
-The L31 Vortec head will bolt directly onto Gen 1 small block Chevrolets. They will also obviously work on L31 engines (sometimes referred to as Gen1+). They are not compatible with Gen2 (LT1 or LT4) engines. They are also not compatible with any of the current LS engines.
+The L31 Vortec head can be used on any SBC engine from 1955 through the end of Vortec production, with the exception of the Gen 2 LT1/LT4 engines used in some vehicles between 1992-'97. They are also not compatible with any of the current LS engines.
 There are some inherent costs associated in swapping from 1995-back heads to the L31 Vortec heads. Here is a list of items to be purchased and/or labor associated with the upgrade:
@@ Line 160: / Line 160: @@
 * Springs if the cam has a valve lift over about 0.420"
 * Center bolt style valve covers if the heads used previously were perimeter style
-[[File:Vortec valve-rocker.jpg|thumb|right|300px|Self aligning stamped steel rockers]]
+** Note: [http://www.crankshaftcoalition.com/wiki/Vortec_L31_cylinder_head#Small_port_Vortec_head_p.2Fn_25534351_.28bare.29_and_p.2Fn_25534421_.28assembled.29 GMPP small and large port Vortec heads] and other aftermarket Vortec heads accept either perimeter or center bolt valve covers[[File:Vortec valve-rocker.jpg|thumb|right|300px|Self aligning stamped steel rockers]]
-** Note: [http://www.crankshaftcoalition.com/wiki/Vortec_L31_cylinder_head#Small_port_Vortec_head_p.2Fn_25534351_.28bare.29_and_p.2Fn_25534421_.28assembled.29 GMPP small and large port Vortec heads] and other aftermarket Vortec heads accept either perimeter or center bolt valve covers
 *Self aligning rocker arms
 * Valve cover gaskets
@@ Line 185: / Line 184: @@
 The stock Vortec valve springs are single wound without a damper and are 1.250" diameter. The damping is done by the spring ID (.880") being a close fit to the guide boss OD (0.845"); this damps the spring without the added cost of an inner flat wound damper seen on the Gen 1 SBC throughout its production. If you have aftermarket springs designed for the earlier heads, you must remove the inner damper because the damper ID will be too small to fit over the guide boss without it being cut smaller. If the boss is cut smaller, a damper should be used.
-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=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)
+*'''[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"''' <br>
-{{Note1}}The p/n26918 springs were updated, check w/Comp Cams to be sure the specs are current.
+{{Note1}}The p/n 26918 springs requires the spring pocket be opened up using Comp Cams tool p/n 4721 or equivalent so there's no binding. The p/n 26918 springs were updated, check w/Comp Cams to be sure these 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"
@@ Line 206: / Line 205: @@
 ===Other springs===
-The following valve springs are single w/either no damper or damper removed. They fit the stock seat and retainer unless otherwise noted.
+The following valve springs are single w/either no damper or damper removed. They fit the stock seat, guide boss, seal, and retainer unless otherwise noted.
 *Comp p/n 981
@@ Line 225: / Line 224: @@
 **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 (p/n unknown) break the dampers on a 0.480" net lift hydraulic cam SBC application. Whether these problems were transient or ongoing is unknown. If these springs are being considered, research them first.
 ===Locks===
@@ Line 242: / Line 241: @@
 ===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 caution if making the seat larger, there have been a few warnings about cracks developing on heads with enlarged seats. Maximum spring seat diameter is 1.44". 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. 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==
@@ Line 250: / Line 249: @@
 [[File:VORTEC GUIDE BOSS MODIFIED.jpg|thumb|250px|Before (right) and after]]
-In order to fit one of the commonly available smaller diameter positive type valve stem oil seals, the tops of the guide boss needs to be turned down. To fit springs with a smaller ID like doubles or those with a damper, the guide boss needs to be modified by shortening and decreasing the OD of the boss.
+In order to fit one of the commonly available smaller diameter positive type valve stem oil seals, the tops of the guide boss needs to be turned down. To fit springs with a smaller ID like double springs or springs that use a damper, the guide boss needs to be modified by shortening and decreasing the OD of the boss.
 <br style="clear:both"/>
@@ Line 375: / Line 374: @@
 ==Recommended spark plugs==
 The exact heat range depends on several factors. This is a guide that will get you in the ballpark. Carefully assess the heat range before settling on a plug for your particular combination.
-* AC Delco Rapid Fire Spark Plugs R44LTS
+* AC Delco Rapidfire Spark Plugs R44LTS
-* AC Delco Rapid Fire Spark Plugs MR43LTS
+* AC Delco Rapidfire Spark Plugs MR43LTS
 * AC Delco Rapidfire No 3 Spark Plug
-* ACCEL P526S U-Groove “SHORTY” Double Platinum (approximately 3/16″ shorter than AC R44LTS)
+* Accel P526S U-Groove “shorty” Double Platinum (approximately 3/16″ shorter than AC R44LTS)
-* ACCEL 516
+* Accel 516
 * Autolite 26
 * Autolite 104
@@ Line 632: / Line 631: @@
 <span class="wbg-blacktext-12pxB">Example:</span> 12-235-2 Comp Cam Extreme 4 X 4, flat tappet cam, lift I .447”, E .462”, duration @ .050” 210 I, 218 E.
-Strong low end and mid range torque. Excellent cam for R.V., and pickups when changing to the Vortec heads.<br>
+Strong low end and mid range torque. Excellent cam for RV's and pickups when changing to the Vortec heads.<br>
 <span class="wbg-blacktext-12pxB">Note:</span> Valve spring change is required with this cam.</td>
@@ Line 682: / Line 681: @@
 <td class="wbg-blacktext" align="center" valign="top">
-Holley Custom, Cast Aluminum, Ball-Milled Top, Valve Covers. The rigid 1-piece aluminum castings combine strength and light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise.
+Holley custom cast aluminum valve covers with ball-milled top. The rigid 1-piece aluminum castings combine strength and light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise.
 </td>
@@ Line 694: / Line 693: @@
 <td class="wbg-blacktext" align="center" valign="top">
-Holley Custom, Cast Aluminum, Polished Flat Top, Valve Covers. The rigid 1-pc aluminum castings combine strength and
+Holley custom cast aluminum valve covers with polished flat top. The rigid 1-pc aluminum castings combine strength and light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise.
-light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise.
 </td>
@@ Line 708: / Line 705: @@
 <td class="wbg-blacktext" align="center" valign="top">
-MR Gasket, 1987-up SBC, center hold down, baffled. Included: 2 covers, 1 oil fill cap, 2 PCV/breather grommets.)
+Mr Gasket, 1987-up SBC, center hold down, baffled. Included: 2 covers, 1 oil fill cap, 2 PCV/breather grommets.
 </td>
@@ Line 724: / Line 721: @@
 <td class="wbg-blacktext" align="center" valign="top">10309-1</td>
-<td class="wbg-blacktext" align="center" valign="top">Crane Cams valve spring and retainer kit. (drop-in springs with no machine work needed)</td>
+<td class="wbg-blacktext" align="center" valign="top">Crane Cams valve spring and retainer kit. Drop-in springs with no machine work needed.</td>
 </tr>
@@ Line 744: / Line 741: @@
 <td class="wbg-blacktext" align="center" valign="top">10105117</td>
-<td class="wbg-blacktext" align="center" valign="top">GM Composition Head Gasket, .028” thick compressed. (price is for one gasket)</td>
+<td class="wbg-blacktext" align="center" valign="top">GM Composition Head Gasket, 0.028” thick compressed. </td>
 </tr>
@@ Line 752: / Line 749: @@
 <td class="wbg-blacktext" align="center" valign="top">12557236</td>
-<td class="wbg-blacktext" align="center" valign="top">GM Composition Head Gasket, .051” thick compressed. (price is for one gasket)</td>
+<td class="wbg-blacktext" align="center" valign="top">GM Composition Head Gasket, 0.051” thick compressed. </td>
 </tr>