Milling cylinder heads

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(Created page with "==Overview== When the decks of the block or heads are milled to raise compression (usually the heads are milled to raise the CR), or to correct the [http://www.crankshaftcoal...")
 
(→Intake flange angles)
 
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==Overview==
 
==Overview==
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When the decks of the block or heads are milled to raise compression (usually the heads are milled to raise the CR), or to correct the [http://www.crankshaftcoalition.com/wiki/Quench '''quench measurement'''] (the block is milled for correcting quench), or to true the surfaces, often the intake flanges and the ends of the intake manifold (or the surfaces of the block, or a combination of them both) need to be milled to correct the port and bolt hole alignment.  
+
Cylinder heads are milled to raise compression or to correct the deck surface if it's warped or otherwise out of spec.
  
−
==Mill the heads or the intake manifold?==
+
==How much to mill==
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It is better to keep all the modifications to the cylinder head or intake manifold- one or the other. Otherwise, the heads and intake become basically inseparable. On engines that show an amount to be removed from the ends in the table below, do a mock up ''before'' milling because in cases where the intake seals the lifter valley (like the SBC) there may be enough clearance without milling the ends. Always seal the ends using RTV whenever possible. On engines that use a separate valley cover, the ends need to be checked.
+
Generally speaking the less that's milled beyond what is needed to true the surfaces, the better. Care should be used when milling production heads because the castings are generally none too thick. Even so, builders have milled stock SBC heads all the way to where the intake seat is almost flush w/the deck surface, or to where the cooling passages around the spark plug are removed. Milling 0.125"-plus is not unusual, but this is usually only done where a race track/series has rules regarding what cylinder heads can be used. This is often "open chamber" SBC heads as was used in the smog years, the idea being the costs associated with engine building will be less using these commonly available heads.
  
−
==How much to mill the decks==
+
The compression ratio can also be raised by using a thinner head gasket. Only when the thinnest practical head gasket is used should milling be considered. Not only are head gaskets cheaper than milling, but the decks will be thicker with less milling. As an example, the difference between a 0.041" thick head gasket and a 0.015" head gasket is almost 0.75:1 on a 350 SBC.
−
Whether milling the intake mounting surfaces is necessary and how much needs to be removed depends on the angles involved and how much material was removed from the decks.  
+
  
−
It should be taken into consideration that when the heads are milled, the [http://www.crankshaftcoalition.com/wiki/Valve_train_geometry '''valve train geometry'''] changes and [http://www.crankshaftcoalition.com/wiki/Valve_train_points_to_check piston to valve clearances] will be closer.  
+
{{Note1}}It should be taken into consideration that when the heads are milled or a thinner head gasket used, the [http://www.crankshaftcoalition.com/wiki/Valve_train_geometry '''valve train geometry'''] changes, the [http://www.crankshaftcoalition.com/wiki/Valve_train_points_to_check piston to valve clearances] will be closer, as well as the [http://www.crankshaftcoalition.com/wiki/Quench '''quench measurement'''] will be reduced.
 +
 
 +
==Correcting the intake flange==
 +
Whenever the block or heads are milled, often the intake flanges and the ends of the intake manifold (or the surfaces of the block, or a combination of them both) need to be milled to correct the port and bolt hole alignment.
 +
 
 +
===Mill the heads or the intake manifold?===
 +
Often, builders opt to mill only the heads so any off the shelf intake manifold will fit the engine. In any event, it is better to keep all the modifications to either the cylinder head or intake manifold- one or the other. Otherwise, the heads and intake become basically inseparable.
 +
 
 +
On engines that show an amount to be removed from the ends in the table below, do a mock up ''before'' milling because in cases where the intake seals the lifter valley (like the SBC) there may be enough clearance without milling the ends. Always seal the ends using RTV whenever possible. On engines that use a separate valley cover, the ends need to be checked.
 +
 
 +
===How much to mill the decks===
 +
Whether milling the intake mounting surfaces is necessary and how much needs to be removed depends on the angles involved and how much material was removed from the decks.  
  
 
While there are math formulas for this, the table below is quick and easy to use.  
 
While there are math formulas for this, the table below is quick and easy to use.  
  
−
{{Note1}}The figures below are used when ''flat milling'' the decks.
+
{{Note1}}The figures below are used when '''''flat milling''''' the decks.
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<br>
+
;All measurements are in inches.
−
<table bgcolor="#eeeeee" border="2" cellpadding="1" width="98%">
+
<table border="2" cellpadding="2" cellspacing="0" width="98%">
−
     <tr>
+
     <tr bgcolor="#DDDFFF">
−
         <td align="center" width="200"><p align="center"><font color="black"><strong>Engine/Head Type</strong></font></p>
+
         <td align="center" width="200"><p align="center"><font color="black">'''Engine/Head Type'''</font></p>
 
         </td>
 
         </td>
−
         <td align="center" width="300"><p align="center"><font color="black"><strong>Amount in inches to reduce chamber volume by 1cc</strong></font></p>
+
         <td align="center" width="300"><p align="center"><font color="black">'''Amount to reduce chamber volume by 1cc'''</font></p>
 
         </td>
 
         </td>
−
         <td align="center" width="300"><p align="center"><font color="black"><strong>Amount in inches to mill intake flanges for each 0.010 removed from heads or block</strong></font></p>
+
         <td align="center" width="300"><p align="center"><font color="black">'''Amount to mill intake flanges for each 0.010" removed from heads or block'''</font></p>
 
         </td>
 
         </td>
−
         <td align="center" width="200"><p align="center"><font color="black"><strong>Amount in inches to mill intake ends for each 0.010 removed from heads or block</strong></font></p>
+
         <td align="center" width="200"><p align="center"><font color="black">'''Amount to mill intake ends for each 0.010" removed from heads or block'''</font></p>
 
         </td>
 
         </td>
 
     </tr>
 
     </tr>
 
     <tr>
 
     <tr>
−
         <td align="center" width="200">SBC 64cc chamber</td>
+
         <td align="center" width="200">'''SBC 64cc chamber'''</td>
−
         <td align="center" width="200"><strong>0.0055</strong></td>
+
         <td align="center" width="200">0.0055</td>
−
         <td align="center" width="200"><strong>0.0123</strong></td>
+
         <td align="center" width="200">0.0123</td>
−
         <td align="center" width="200"><strong>0.0173</strong></td>
+
         <td align="center" width="200">0.0173</td>
 
     </tr>
 
     </tr>
−
     <tr>
+
     <tr bgcolor="#F1F1F1">
−
         <td align="center" width="200">SBC 76cc chamber</td>
+
         <td align="center" width="200">'''SBC 76cc chamber'''</td>
−
         <td align="center" width="200"><strong>0.0059</strong></td>
+
         <td align="center" width="200">0.0059</td>
−
         <td align="center" width="200"><strong>0.0123</strong></td>
+
         <td align="center" width="200">0.0123</td>
−
         <td align="center" width="200"><strong>0.0173</strong></td>
+
         <td align="center" width="200">0.0173</td>
 
     </tr>
 
     </tr>
 
     <tr>
 
     <tr>
−
         <td align="center" width="200">BBC 109cc closed chamber</td>
+
         <td align="center" width="200">'''BBC 109cc closed chamber'''</td>
−
         <td align="center" width="200"><strong>0.0065</strong></td>
+
         <td align="center" width="200">0.0065</td>
−
         <td align="center" width="200"><strong>0.0070</strong></td>
+
         <td align="center" width="200">0.0070</td>
−
         <td align="center" width="200"><strong>0.0193</strong></td>
+
         <td align="center" width="200">0.0193</td>
 
     </tr>
 
     </tr>
−
     <tr>
+
     <tr bgcolor="#F1F1F1">
−
         <td align="center" width="200">BBC 118cc open chamber</td>
+
         <td align="center" width="200">'''BBC 118cc open chamber'''</td>
−
         <td align="center" width="200"><strong>0.0050</strong></td>
+
         <td align="center" width="200">0.0050</td>
−
         <td align="center" width="200"><strong>0.0070</strong></td>
+
         <td align="center" width="200">0.0070</td>
−
         <td align="center" width="200"><strong>0.0193</strong></td>
+
         <td align="center" width="200">0.0193</td>
 
     </tr>
 
     </tr>
 
     <tr>
 
     <tr>
−
         <td align="center" width="200">Ford 1965-'77 289-302 engine</td>
+
         <td align="center" width="200">'''Ford 1965-'77 289-302'''</td>
−
         <td align="center" width="200"><strong>0.0060</strong></td>
+
         <td align="center" width="200">0.0060</td>
−
         <td align="center" width="200"><strong>0.0100</strong></td>
+
         <td align="center" width="200">0.0100</td>
−
         <td align="center" width="200"><strong>0.0143</strong></td>
+
         <td align="center" width="200">0.0143</td>
 
     </tr>
 
     </tr>
−
     <tr>
+
     <tr bgcolor="#F1F1F1">
−
         <td align="center" width="200">Ford 1969-'77 351W engine</td>
+
         <td align="center" width="200">'''Ford 1969-'77 351W'''</td>
−
         <td align="center" width="200"><strong>0.0055</strong></td>
+
         <td align="center" width="200">0.0055</td>
−
         <td align="center" width="200"><strong>0.0100</strong></td>
+
         <td align="center" width="200">0.0100</td>
−
         <td align="center" width="200"><strong>0.0143</strong></td>
+
         <td align="center" width="200">0.0143</td>
 
     </tr>
 
     </tr>
 
     <tr>
 
     <tr>
−
         <td align="center" width="200">Ford 1978-up 302/5.0L/351W
+
         <td align="center" width="200">'''Ford 1978-up 302/5.0L/351W'''<br>
−
         engines except 86 5.0 HO</td>
+
         (except 1986 5.0 HO)</td>
−
         <td align="center" width="200"><strong>0.0045</strong></td>
+
         <td align="center" width="200">0.0045</td>
−
         <td align="center" width="200"><strong>0.0100</strong></td>
+
         <td align="center" width="200">0.0100</td>
−
         <td align="center" width="200"><strong>0.0143</strong></td>
+
         <td align="center" width="200">0.0143</td>
 
     </tr>
 
     </tr>
−
     <tr>
+
     <tr bgcolor="#F1F1F1">
−
         <td align="center" width="200">Ford 351C engine</td>
+
         <td align="center" width="200">'''Ford 351C'''</td>
−
         <td align="center" width="200"><strong>0.0050</strong></td>
+
         <td align="center" width="200">0.0050</td>
−
         <td align="center" width="200"><strong>0.0100</strong></td>
+
         <td align="center" width="200">0.0100</td>
−
         <td align="center" width="200"><strong>0.0143</strong></td>
+
         <td align="center" width="200">0.0143</td>
 
     </tr>
 
     </tr>
 
     <tr>
 
     <tr>
−
         <td align="center" width="200">Ford 385 Series with quench-type head</td>
+
         <td align="center" width="200">'''Ford 385 Series with quench-type head'''</td>
−
         <td align="center" width="200"><p align="center"><strong>.0050</strong></p>
+
         <td align="center" width="200"><p align="center">.0050</p>
 
         </td>
 
         </td>
−
         <td align="center" width="200"><strong>0.0100</strong></td>
+
         <td align="center" width="200">0.0100</td>
−
         <td align="center" width="200"><strong>0.0143</strong></td>
+
         <td align="center" width="200">0.0143</td>
 
     </tr>
 
     </tr>
−
     <tr>
+
     <tr bgcolor="#F1F1F1">
−
         <td align="center" width="200">Ford 385 Series with open chamber head</td>
+
         <td align="center" width="200">'''Ford 385 Series with open chamber head'''</td>
−
         <td align="center" width="200"><p align="center"><strong>.0030</strong></p>
+
         <td align="center" width="200"><p align="center">.0030</p>
 
         </td>
 
         </td>
−
         <td align="center" width="200"><strong>0.0100</strong></td>
+
         <td align="center" width="200">0.0100</td>
−
         <td align="center" width="200"><strong>0.0143</strong></td>
+
         <td align="center" width="200">0.0143</td>
 
     </tr>
 
     </tr>
 
     <tr>
 
     <tr>
−
         <td align="center" width="200">Chrysler 273, 318ci "LA" engine with 57-61cc chamber</td>
+
         <td align="center" width="200">'''Chrysler 273, 318ci "LA" with 57-61cc chamber'''</td>
−
         <td align="center" width="200"><strong>0.0053</strong></td>
+
         <td align="center" width="200">0.0053</td>
−
         <td align="center" width="200"><strong>0.0095</strong></td>
+
         <td align="center" width="200">0.0095</td>
−
         <td align="center" width="200"><strong>0.0144</strong></td>
+
         <td align="center" width="200">0.0144</td>
 
     </tr>
 
     </tr>
−
     <tr>
+
     <tr bgcolor="#F1F1F1">
−
         <td align="center" width="200">Chrysler 340-360ci "LA" engine with 63-71cc chamber</td>
+
         <td align="center" width="200">'''Chrysler 340-360ci "LA" with 63-71cc chamber'''</td>
−
         <td align="center" width="200"><strong>0.0048</strong></td>
+
         <td align="center" width="200">0.0048</td>
−
         <td align="center" width="200"><strong>0.0095</strong></td>
+
         <td align="center" width="200">0.0095</td>
−
         <td align="center" width="200"><strong>0.0144</strong></td>
+
         <td align="center" width="200">0.0144</td>
 
     </tr>
 
     </tr>
 
     <tr>
 
     <tr>
−
         <td align="center" width="200">Chrysler B/RB engine with 66.5cc or 73.5cc chamber</td>
+
         <td align="center" width="200">'''Chrysler B/RB with 66.5cc or 73.5cc chamber'''</td>
−
         <td align="center" width="200"><strong>0.0062</strong></td>
+
         <td align="center" width="200">0.0062</td>
−
         <td align="center" width="200"><strong>0.0123</strong></td>
+
         <td align="center" width="200">0.0123</td>
−
         <td align="center" width="200"><strong>Not required</strong></td>
+
         <td align="center" width="200">Not required</td>
 
     </tr>
 
     </tr>
−
     <tr>
+
     <tr bgcolor="#F1F1F1">
−
         <td align="center" width="200">Chrysler B/RB engine with 79/81/83cc
+
         <td align="center" width="200">'''Chrysler B/RB with 79/81/83cc chamber'''</td>
−
        chamber</td>
+
         <td align="center" width="200">0.0042</td>
−
         <td align="center" width="200"><strong>0.0042</strong></td>
+
         <td align="center" width="200">0.0123</td>
−
         <td align="center" width="200"><strong>0.0123</strong></td>
+
         <td align="center" width="200">Not required</td>
−
         <td align="center" width="200"><strong>Not required</strong></td>
+
 
     </tr>
 
     </tr>
 
     <tr>
 
     <tr>
−
         <td align="center" width="200">Chrysler B/RB Max Wedge
+
         <td align="center" width="200">'''Chrysler B/RB Max Wedge with 81 or 86cc chamber'''</td>
−
        engine with 81 or 86cc chamber</td>
+
         <td align="center" width="200">0.0050</td>
−
         <td align="center" width="200"><strong>0.0050</strong></td>
+
         <td align="center" width="200">0.0120</td>
−
         <td align="center" width="200"><strong>0.0120</strong></td>
+
         <td align="center" width="200">0.0170</td>
−
         <td align="center" width="200"><strong>0.0170</strong></td>
+
 
     </tr>
 
     </tr>
−
     <tr>
+
     <tr bgcolor="#F1F1F1">
−
         <td align="center" width="200">Olds 403-455 Big Block
+
         <td align="center" width="200">'''Olds 403-455'''</td>
−
        engines</td>
+
         <td align="center" width="200">.0050</td>
−
         <td align="center" width="200"><strong>.0050</strong></td>
+
         <td align="center" width="200">.0130</td>
−
         <td align="center" width="200"><strong>.0130</strong></td>
+
         <td align="center" width="200">.0169</td>
−
         <td align="center" width="200"><strong>.0169</strong></td>
+
 
     </tr>
 
     </tr>
 
     <tr>
 
     <tr>
−
         <td align="center" width="200">Olds 350 Small Block
+
         <td align="center" width="200">'''Olds 350'''</td>
−
        engine </td>
+
         <td align="center" width="200">.0060</td>
−
         <td align="center" width="200"><strong>.0060</strong></td>
+
         <td align="center" width="200">.0130</td>
−
         <td align="center" width="200"><strong>.0130</strong></td>
+
         <td align="center" width="200">.0169</td>
−
         <td align="center" width="200"><strong>.0169</strong></td>
+
 
     </tr>
 
     </tr>
−
     <tr>
+
     <tr bgcolor="#F1F1F1">
−
         <td align="center" width="200">Pontiac 1965-'67</td>
+
         <td align="center" width="200">'''Pontiac 1965-'67'''</td>
−
         <td align="center" width="200"><strong>0.0061</strong></td>
+
         <td align="center" width="200">0.0061</td>
−
         <td align="center" width="200"><strong>0.0061</strong></td>
+
         <td align="center" width="200">0.0061</td>
−
         <td align="center" width="200"><strong>Not required</strong></td>
+
         <td align="center" width="200">Not required</td>
 
     </tr>
 
     </tr>
 
     <tr>
 
     <tr>
−
         <td align="center" width="200">Pontiac 1968-'70</td>
+
         <td align="center" width="200">'''Pontiac 1968-'70'''</td>
−
         <td align="center" width="200"><strong>0.0052</strong></td>
+
         <td align="center" width="200">0.0052</td>
−
         <td align="center" width="200"><strong>0.0052</strong></td>
+
         <td align="center" width="200">0.0052</td>
−
         <td align="center" width="200"><strong>Not required</strong></td>
+
         <td align="center" width="200">Not required</td>
 
     </tr>
 
     </tr>
−
     <tr>
+
     <tr bgcolor="#F1F1F1">
−
         <td align="center" width="200">Pontiac 1971-'79</td>
+
         <td align="center" width="200">'''Pontiac 1971-'79'''</td>
−
         <td align="center" width="200"><strong>0.0047</strong></td>
+
         <td align="center" width="200">0.0047</td>
−
         <td align="center" width="200"><strong>0.0047</strong></td>
+
         <td align="center" width="200">0.0047</td>
−
         <td align="center" width="200"><strong>Not required</strong></td>
+
         <td align="center" width="200">Not required</td>
 
     </tr></table>
 
     </tr></table>
−
<br><br>
+
 
−
==Intake flange angles==
+
−
For those who would prefer to calculate it for themselves, the table below gives the intake flange angles. The amounts shown are how much difference there is from 90 degrees between the flange and deck. The flange angles listed below may be used with the following formula:
+
−
;Amount to be removed from intake flange = .707 ÷ (SIN (45 - intake face angle))
+
 
<br>
 
<br>
−
<table bgcolor="#eeeeee" border="2" cellpadding="1" width="98%">
 
−
<tr valign="TOP"><td colspan="5" align="center"><b>Common V8 intake flange angles </b></td></tr>
 
−
<tr><td><b>Make</b></td><td><b>Engine</b></td><td><b>Displacement</b></td><td align="center"><b>Intake flange angle</b></td></tr>
 
−
<tr valign="TOP"><td>Chevrolet</td><td>SB 1955-up</td><td>262, 265, 267, 283, 302, 305, 307, 327, 350, 400</td><td align="center">'''10°'''</td></tr>
 
−
<tr valign="TOP"><td rowspan="7">Chrysler</td><td>“LA” 1964-up</td><td>273, 318, 340, 360</td><td align="center">'''-3°'''</td></tr>
 
−
<tr valign="TOP"><td>“B/RB” 1958-'78</td><td>350, 361, 383, 400, 413, 426W, 440</td><td align="center">'''10°'''</td></tr>
 
−
<tr valign="TOP"><td>Mopar Hemi 1964-'71</td><td>426</td><td align="center">'''-13°'''</td></tr>
 
−
<tr valign="TOP"><td>Chrysler Hemi 1951-'58</td><td>331, 354, 392</td><td rowspan="3" align="center">'''25°'''</td></tr>
 
−
<tr valign="TOP"><td>DeSoto Hemi 1952-'57</td><td>276, 291, 330, 341, 345</td></tr>
 
−
<tr valign="TOP"><td nowrap="">Dodge Hemi &amp; Poly 1953-'58</td><td>241, 259, 270, 315, 325</td></tr>
 
−
<tr valign="TOP"><td>Poly “A” 1956-'67</td><td>277, 301, 303, 318, 326</td><td align="center">'''10°'''</td></tr>
 
−
<tr valign="TOP"><td rowspan="3">Ford</td><td>SB 1962-up</td><td>221, 260, 289, 302, 351, 400</td><td rowspan="3" align="center">'''0°'''</td></tr>
 
−
<tr valign="TOP"><td>FE 1958-'76</td><td>332, 352, 390, 406, 410, 427, 428</td></tr>
 
−
<tr valign="TOP"><td>385 Series 1968-'97</td><td>370, 385, 429, 460</td></tr>
 
−
<tr valign="TOP"><td rowspan="2">Oldsmobile</td><td>1949-'63 “Rocket”</td><td>303, 324, 371, 394</td><td align="center">'''20°'''</td></tr>
 
−
<tr valign="TOP"><td>1964-up (late)</td><td>260, 307, 330, 350, 400, 403, 425, 455</td><td align="center">'''0°'''</td></tr>
 
−
<tr valign="TOP"><td rowspan="2">Pontiac</td><td>1955-'79</td><td>265, 287, 301, 316, 347, 326, 350, 370, 389, 400, 421, 428, 455</td><td align="center">'''0°'''</td></tr>
 
−
</table>
 
−
 
 
==Another way to calculate the amount to remove==
 
==Another way to calculate the amount to remove==
−
In cases where the head in question isn't listed or the list cannot be accessed, the amount of material to remove from the cylinder head deck to reach a specific volume can be found by using a graduated burette or even a syringe.
+
In cases where the head in question isn't listed or the list cannot be accessed, the amount of material to remove from the cylinder head deck to reach a specific volume can be estimated by using a graduated burette or even a large syringe.
  
 
Assuming the target chamber volume is known, a burette or syringe can be used to dispense that amount of fluid into the chamber. Then measure down to the surface of the fluid and that will be the amount of material that needs to be removed from the deck.
 
Assuming the target chamber volume is known, a burette or syringe can be used to dispense that amount of fluid into the chamber. Then measure down to the surface of the fluid and that will be the amount of material that needs to be removed from the deck.
  
 
Using a fluid other than water will make this easier, since water has a relatively high surface tension. Mineral spirits or rubbing alcohol with a drop or two of food coloring works well for this.
 
Using a fluid other than water will make this easier, since water has a relatively high surface tension. Mineral spirits or rubbing alcohol with a drop or two of food coloring works well for this.
 +
 +
==CC'ing the chambers==
 +
[[File:Cc chamber.jpg]]
  
 
==Resources==
 
==Resources==
 +
*[http://www.crankshaftcoalition.com/wiki/Dynamic_compression_ratio#Online_calculators Online compression ratio calculators]
 
*[[Valve train points to check]]
 
*[[Valve train points to check]]
 +
*[[Quench]]
 +
*[[Valve train geometry]]
 
*[[Head gasket]]
 
*[[Head gasket]]
−
*[[Dynamic compression ratio]]
 
 
<br><br>
 
<br><br>
 +
 
{{newarticle1}}  
 
{{newarticle1}}  
  
 
[[Category:Engine]]
 
[[Category:Engine]]
 
[[Category: Cylinder head]]
 
[[Category: Cylinder head]]

Latest revision as of 22:32, 3 March 2015

Retrieved from "https://www.crankshaftcoalition.com/wiki/index.php?title=Milling_cylinder_heads&oldid=800914"
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