--===============5322088116913435035==
Content-Language: en-US
boundary="_000_BN6PR14MB14577B7D97F7CAC15DABE844FA749BN6PR14MB1457namp_"
--_000_BN6PR14MB14577B7D97F7CAC15DABE844FA749BN6PR14MB1457namp_
Content-Transfer-Encoding: quoted-printable
I appreciate all the advice. This is why I have subscribed to this list for=
24 years.
I had measured the head height on the car and that figure was not accurate,=
or my eyeball didn=92t read the scale correctly.
Off the car now and on the bench the head measures 3.180=94 which means it =
has had 0.150=94 cut away. This is the limit which Kastner describes. The =
chambers have had some radiusing, not as much as is described in Kastner=92=
s book.
Since I=92m not building a race car, and prioritize reliability over perfor=
mance, I think I will look for a different head.
If anyone knows someone looking for a usable head for a race car, perhaps I=
have what they need.
Oh, and the pushrods are 257mm in length, which is the shorter set sold by =
Revington TR (stock is 260mm).
Cliff
Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=3D550986> for Window=
s 10
Sent: Wednesday, April 7, 2021 3:24 PM
Subject: [TR] Advice on high compression head
The telenovela =93What=92s going on with this 4A cylinder head=94 has devel=
oped a new plot twist.
The head, after cleanup, measures 3.21=94 from bottom to the surface for th=
e valve cover gasket. Stock is 3.330 (if I got the number correctly). Some =
PO cut 0.11 off, because only 0.010=94 was removed in this round of clean u=
p. Now I can see an explanation for the persistent pinging I=92ve dealt wit=
h over the last few years (head has been milled so compression is high, mat=
erial near intake valves has been thinned, increasing likelihood of hot spo=
ts =96 I=92m getting this from Kastner=92s preparation book), which I had t=
hought was due to leaking intakes, carb shafts, or operating at higher alti=
tude.
As is, I can=92t use this head because there is not enough slack in the val=
ve train to give 0.010=94 clearance on several valves. I didn=92t notice be=
fore, but now that I am looking, all the valve adjusters were nearly backed=
out all the way.
Looking for advice from the list: is there any reasonable way to use this h=
ead?
- I=92d prefer to reduce compression but don=92t see any reasonable way to =
accomplish that. I called GasketWorks and he gently discouraged me from get=
ting a custom thick head gasket, saying instead I=92d be better off finding=
a head which had not been milled so much.
- Shimming the rocker pedestals to get valve clearance feels like a bandai=
d which certainly won=92t address the pinging (assuming that the pinging is=
a result of the shortened head).
Would appreciate any advice on the way forward.
Cliff
Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=3D550986> for Window=
s 10
--_000_BN6PR14MB14577B7D97F7CAC15DABE844FA749BN6PR14MB1457namp_
Content-Transfer-Encoding: quoted-printable
<html xmlns:o=3D"urn:schemas-microsoft-com:office:office" xmlns:w=3D"urn:sc=
hemas-microsoft-com:office:word" xmlns:m=3D"http://schemas.microsoft.com/of=
fice/2004/12/omml" xmlns=3D"http://www.w3.org/TR/REC-html40";>
<head>
<meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3DWindows-1=
252">
<meta name=3D"Generator" content=3D"Microsoft Word 15 (filtered medium)">
<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;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style>
</head>
<body lang=3D"EN-US" link=3D"blue" vlink=3D"#954F72" style=3D"word-wrap:bre=
ak-word">
<div class=3D"WordSection1">
<p class=3D"MsoNormal">I appreciate all the advice. This is why I have subs=
cribed to this list for 24 years.</p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">I had measured the head height on the car and that f=
igure was not accurate, or my eyeball didn=92t read the scale correctly.</p=
>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Off the car now and on the bench the head measures 3=
.180=94 which means it has had 0.150=94 cut away. This is the limit w=
hich Kastner describes. The chambers have had some radiusing, not as much a=
s is described in Kastner=92s book.
</p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Since I=92m not building a race car, and prioritize =
reliability over performance, I think I will look for a different head.&nbs=
p;
</p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">If anyone knows someone looking for a usable head fo=
r a race car, perhaps I have what they need.</p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Oh, and the pushrods are 257mm in length, which is t=
he shorter set sold by Revington TR (stock is 260mm).
<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Cliff</p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Sent from <a href=3D"https://go.microsoft.com/fwlink=
/?LinkId=3D550986">
Mail</a> for Windows 10</p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<div style=3D"mso-element:para-border-div;border:none;border-top:solid #E1E=
1E1 1.0pt;padding:3.0pt 0in 0in 0in">
<p class=3D"MsoNormal" style=3D"border:none;padding:0in"><b>From: </b><a hr=
ef=3D"mailto:cliff_hansen@outlook.com";>Cliff Hansen</a><br>
<b>Sent: </b>Wednesday, April 7, 2021 3:24 PM<br>
<b>To: </b><a href=3D"mailto:triumphs@autox.team.net";>list Triumph</a><br>
<b>Subject: </b>[TR] Advice on high compression head</p>
</div>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">The telenovela =93What=92s going on with this 4A cyl=
inder head=94 has developed a new plot twist.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">The head, after cleanup, measures 3.21=94 from botto=
m to the surface for the valve cover gasket. Stock is 3.330 (if I got the n=
umber correctly). Some PO cut 0.11 off, because only 0.010=94 was removed i=
n this round of clean up. Now I can see
an explanation for the persistent pinging I=92ve dealt with over the last =
few years (head has been milled so compression is high, material near intak=
e valves has been thinned, increasing likelihood of hot spots =96 I=92m get=
ting this from Kastner=92s preparation book),
which I had thought was due to leaking intakes, carb shafts, or operating =
at higher altitude.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">As is, I can=92t use this head because there is not =
enough slack in the valve train to give 0.010=94 clearance on several valve=
s. I didn=92t notice before, but now that I am looking, all the valve adjus=
ters were nearly backed out all the way.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Looking for advice from the list: is there any reaso=
nable way to use this head?<o:p></o:p></p>
<p class=3D"MsoNormal">- I=92d prefer to reduce compression but don=92t see=
any reasonable way to accomplish that. I called GasketWorks and he gently =
discouraged me from getting a custom thick head gasket, saying instead I=92=
d be better off finding a head which had
not been milled so much. <o:p></o:p></p>
<p class=3D"MsoNormal"> - Shimming the rocker pedestals to get valve c=
learance feels like a bandaid which certainly won=92t address the pinging (=
assuming that the pinging is a result of the shortened head).<o:p></o:p></p=
>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Would appreciate any advice on the way forward.<o:p>=
</o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Cliff<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Sent from <a href=3D"https://go.microsoft.com/fwlink=
/?LinkId=3D550986">
Mail</a> for Windows 10<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
</div>
</body>
</html>
--_000_BN6PR14MB14577B7D97F7CAC15DABE844FA749BN6PR14MB1457namp_--
--===============5322088116913435035==
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
** triumphs@autox.team.net **
Archive: http://www.team.net/pipermail/triumphs http://www.team.net/archive
--===============5322088116913435035==--
|