<div dir="auto">What issues with too wide a gap?<br><br><div data-smartmail="gmail_signature">Ira Erbs<br>Portland, OR<br>typos and artifacts are the fault of my phone</div></div><br><div class="gmail_quote"><div dir="ltr">On Sun, Jan 13, 2019, 11:10 AM David P <<a href="mailto:frogeye@porterscustom.com">frogeye@porterscustom.com</a> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<p>Absolutely correct......</p>
<p><br>
</p>
<div class="m_-3760638066444155266moz-cite-prefix">On 1/12/2019 11:26 PM, WILLIAM B
LAWRENCE wrote:<br>
</div>
<blockquote type="cite">
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
I disagree that valve clearances are not critical. As the engine
comes up to temperature the metal parts of the valve train
(valves, lifters, push rods, the head itself and the rocker
shaft towers) increase in length and the valve clearances are
calculated to assure that this expansion isn't allowed to affect
the sealing of the valves on their seats. If the valves are set
too tight they reach a point where they won't touch the seats
and therefore won't seal. Hot gases rushing through the gaps
will quickly erode the valves. Also i<span style="font-family:Calibri,Helvetica,sans-serif;background-color:rgb(255,255,255);display:inline!important">ncreasing the duration and/or lift of the cam has
the effect of the decreasing the length of the opening and
closing ramps on the back side of the cam This reduces the
length of time (dwell) the valve remains on the seat.
Increasing the valve clearance restores the dwell time the
valve needs to transfer its heat load to the cooling system
through the valve seat and the cylinder head. Too little dwell
time or the lack of proper valve sealing are two causes of
burned valves.</span></div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<br>
</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
In my own experience I installed an Isky cam with a grind a
little more aggressive than the 100M cam and set the clearances
to 0.012" per the manual. Within about 2,000 miles the exhaust
valves were trashed. I then took the time to read the Isky
installation instructions which specifically state the valve
clearance needs to be set to 0.018". I re-installed the head
with new valves and set them to Isky's spec and never had
another problem with burned valves.</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<br>
</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
Follow the cam grinder's recommendations and you will avoid
trouble.</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<br>
</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
Bill Lawrence</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
BN1 #554</div>
<hr style="display:inline-block;width:98%">
<div id="m_-3760638066444155266divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b>
Healeys <a class="m_-3760638066444155266moz-txt-link-rfc2396E" href="mailto:healeys-bounces@autox.team.net" target="_blank" rel="noreferrer"><healeys-bounces@autox.team.net></a> on behalf of
Bob Spidell <a class="m_-3760638066444155266moz-txt-link-rfc2396E" href="mailto:bspidell@comcast.net" target="_blank" rel="noreferrer"><bspidell@comcast.net></a><br>
<b>Sent:</b> Saturday, January 12, 2019 11:10 PM<br>
<b>To:</b> Michael MacLean; <a class="m_-3760638066444155266moz-txt-link-abbreviated" href="mailto:healeys@autox.team.net" target="_blank" rel="noreferrer">healeys@autox.team.net</a><br>
<b>Subject:</b> Re: [Healeys] Valve clearances</font>
<div> </div>
</div>
<div style="background-color:#ffffff">
<p>I should note the rockers are pretty noisy at 0.015; IIRC I
tightened them up just a bit.<br>
</p>
<div class="m_-3760638066444155266x_moz-cite-prefix">On 1/12/2019 2:39 PM, Michael
MacLean wrote:<br>
</div>
<blockquote type="cite">
<div class="m_-3760638066444155266x_ydpe1d3e9c5yahoo-style-wrap" style="font-family:times new roman,new york,times,serif;font-size:16px">
<div>I'd go with .016. You can always tighten it. Better
loose than tight.</div>
<div>Mike MacLean<br>
</div>
<div><br>
</div>
</div>
<div id="m_-3760638066444155266x_yahoo_quoted_8268064185" class="m_-3760638066444155266x_yahoo_quoted">
<div>
<div>On Saturday, January 12, 2019, 11:01:32 AM PST, Bob
Spidell <a class="m_-3760638066444155266x_moz-txt-link-rfc2396E" href="mailto:bspidell@comcast.net" target="_blank" rel="noreferrer">
<bspidell@comcast.net></a> wrote: </div>
<div><br>
</div>
<div><br>
</div>
<div>
<div id="m_-3760638066444155266x_yiv1110160614">
<div>
<p>Makes sense (for some reason). I put a DWR1 cam
in my BJ8 which, according to DWR, 'is a little
better than the BJ8 cam and so works well in any
standard or mildly tuned car' but I think the
0.015" applies to all profiles on the spec sheet.<br clear="none">
</p>
<p>Bob<br clear="none">
</p>
<div class="m_-3760638066444155266x_yiv1110160614yqt0287165987" id="m_-3760638066444155266x_yiv1110160614yqt70378">
<div class="m_-3760638066444155266x_yiv1110160614moz-cite-prefix">On
1/11/2019 8:48 PM, John Rowe wrote:<br clear="none">
</div>
</div>
</div>
<div class="m_-3760638066444155266x_yiv1110160614yqt0287165987" id="m_-3760638066444155266x_yiv1110160614yqt92654">
<div>
<div class="m_-3760638066444155266x_yiv1110160614WordSection1">
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span style="color:#1f497d">Simon,</span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span style="color:#1f497d">Modified cams require
the large clearance (don’t ask me why?) So
go for .015 that is what mine is.</span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span style="color:#1f497d">John Rowe</span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span style="color:#1f497d">Qld</span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span style="color:#1f497d">Australia</span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span style="color:#1f497d"> </span></p>
<div>
<div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><b><span style="font-size:10.0pt" lang="EN-US">From:</span></b><span style="font-size:10.0pt" lang="EN-US">
Healeys [<a rel="nofollow noreferrer" shape="rect" class="m_-3760638066444155266x_yiv1110160614moz-txt-link-freetext" href="mailto:healeys-bounces@autox.team.net" target="_blank">mailto:healeys-bounces@autox.team.net</a>]
<b>On Behalf Of </b><a rel="nofollow noreferrer" shape="rect" class="m_-3760638066444155266x_yiv1110160614moz-txt-link-abbreviated" href="mailto:simon.lachlan@alexarevel.plus.com" target="_blank">simon.lachlan@alexarevel.plus.com</a><br clear="none">
<b>Sent:</b> Saturday, 12 January 2019
9:14 AM<br clear="none">
<b>To:</b> Healeys<br clear="none">
<b>Subject:</b> [Healeys] Valve
clearances</span></p>
</div>
</div>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"> </p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span lang="EN-GB">The car is a MkII BT7.</span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span lang="EN-GB">The BMC manual says adjust the
clearances, cold, to 0.012”.</span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span lang="EN-GB">Denis Welch said I should go
0.015”, cold, after fitting their “Fast
Road” cam.</span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span lang="EN-GB">The rolling road guy said
0.016”, warm.</span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span lang="EN-GB"> </span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span lang="EN-GB">I have the radiator out right
now so I can get a nice socket onto that nut
and have a go at the clearances.</span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span lang="EN-GB">Stick with 0.015”, cold?</span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span lang="EN-GB"> </span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span lang="EN-GB">Thanks,</span></p>
<p class="m_-3760638066444155266x_yiv1110160614MsoNormal"><span lang="EN-GB">Simon</span></p>
</div>
<br>
</div>
</div>
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