<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";
color:black;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p
{mso-style-priority:99;
margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";
color:black;}
p.emailquote, li.emailquote, div.emailquote
{mso-style-name:emailquote;
margin-top:0cm;
margin-right:0cm;
margin-bottom:0cm;
margin-left:1.0pt;
margin-bottom:.0001pt;
border:none;
padding:0cm;
font-size:12.0pt;
font-family:"Times New Roman","serif";
color:black;}
span.EmailStyle19
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-AU link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Not sure of the advantages, by my Alfa Romeo GTV is definitely a nicer engine than either of the Healeys or any single cam Japanese car I’ve driven<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>John Rowe<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Qld Australia<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>From:</span></b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> Healeys [mailto:healeys-bounces@autox.team.net] <b>On Behalf Of </b>Bob Spidell<br><b>Sent:</b> Sunday, 9 July 2017 6:00 AM<br><b>To:</b> healeys@autox.team.net<br><b>Subject:</b> [Healeys] Cams - Was: Re: Vernier timing gears<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p>I never understood the advantage of 'twin' cams (assuming two cams per bank of cylinders, one for intake and one for exhaust). Can't the same results come from lobe profiles; i.e. one profile for intake and one for exhaust, on the same cam? All the twin cam setups I've seen have both cams driven by the same belt, so timing will be the same for both cams. Is this idea just to have less 'load' for each cam?<o:p></o:p></p><p><o:p> </o:p></p><p>What does make sense to me is variable cam timing. My Mustang accelerates smoothly and seamlessly, but on coasting deceleration there is a noticeable 'bump' down in RPM around 1,800-2,000 RPM as the ECU changes--advances?--the cam timing, but it only has one cam per bank. I know the Honda VTEC engines have a third lobe, that only comes into play at higher speeds (thanks Edd!).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>On 7/8/2017 12:43 PM, David Porter wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p>I guess my point in generating some "traffic" is best expressed by Mr. Lawrence. With a single cam acting on the valve timing, one can set it close to factory or deviate a couple degrees advanced or retarded for low end torque or high rpm breathing. It is still a trade off versus a twin cam head where both can be affected and gains can be easily (?) obtained for both instances he states. Not too sure we all have easy access to a dyno. These old long stroke 6/4's were designed for grunt. That would be the wise choice. They don't like to be spun up much, then the Welch crank would be necessary. $$ dave<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>On 7/7/2017 7:16 PM, WILLIAM B LAWRENCE wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div id="x_divtagdefaultwrapper"><p><span style='font-family:"Calibri","sans-serif"'>According to Iskendarian You can optimize cam timing either to provide a boost in low end torque by advancing the timing by up to 8 degrees or in high end power by retarding it a similar amount. <o:p></o:p></span></p><p><span style='font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p><p><span style='font-family:"Calibri","sans-serif"'>Since I am looking for a low end boost and will rarely exceed 3500 on the road I set mine 4 degrees in advance.<o:p></o:p></span></p><p><span style='font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p><p><span style='font-family:"Calibri","sans-serif"'>Waiting to see how it works out...<o:p></o:p></span></p><p><span style='font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p><p><span style='font-family:"Calibri","sans-serif"'>Bill Lawrence<o:p></o:p></span></p><p><span style='font-family:"Calibri","sans-serif"'>BN1 #554<o:p></o:p></span></p></div><div class=MsoNormal align=center style='text-align:center'><hr size=2 width="98%" align=center></div><p class=MsoNormal><o:p> </o:p></p></div></blockquote></blockquote><p class=MsoNormal><o:p> </o:p></p></div></body></html>