fot
[Top] [All Lists]

Re: [Fot] TR6 Piston / Head Clearance

To: "'Triumph 'Friends of Triumph'" <fot@autox.team.net>
Subject: Re: [Fot] TR6 Piston / Head Clearance
From: "Steve Yott" <tr4@wi.rr.com>
Date: Fri, 27 May 2016 09:45:00 -0500
Delivered-to: mharc@autox.team.net
Delivered-to: fot@autox.team.net
References: <4ad88e45b29a43f3bf32c409c3cd072c.Gregmogdoc@surfnetusa.com> <CAMJWJcF8_PRT9GXTjjjO0K2CH31gPeKGR_m2gBtxdXb80-7COQ@mail.gmail.com>
Thread-index: AdG3lf1pCC8xt0hPSE6CGOSVDcEk9AAjxOHA
This is a multipart message in MIME format.

--===============6604246436966436090==
        boundary="----=_NextPart_000_002E_01D1B7FC.6FFBF580"
Content-Language: en-us

This is a multipart message in MIME format.

------=_NextPart_000_002E_01D1B7FC.6FFBF580
        charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Since most of you like to play the =E2=80=9Cdeath with pistons=E2=80=9D =
game keep in mind one additional factor as you are building your =
engines.  Over the years I have found crankshafts which were reground =
and the throws were not very precisely indexed.  When a crank is setup =
on the grinding machine for grinding rod journals it is set and reset by =
the number of =E2=80=9Cthrows=E2=80=9D=E2=80=A6 on a 4 cylinder engine =
the grinder has to be indexed twice and on the 6 cylinder, 3 times.  If =
the grinder, either the person or the machine is not perfectly accurate =
you will see variations of TDC for the throws!  I have seen these =
deviations be as much as .006=E2=80=9D when a good grinder will hold =
dimensions within .001=E2=80=9D. =20

=20

So, if you are running close squishes=E2=80=A6. Measure TDC on #1 and #2 =
on the four cylinder and #1, #2 and #3 on the 6 motors=E2=80=A6.. this =
way to can make sure your throws and TDC=E2=80=99s are spot on.

=20

Steve Yott

=20

=20

From: John Styduhar [mailto:johnstydo@gmail.com]=20
Sent: Thursday, May 26, 2016 4:32 PM
To: Gregmogdoc@surfnetusa.com
Cc: Charly Mitchel; Steve Yott; Jim Gray; Triumph 'Friends of Triumph
Subject: Re: [Fot] TR6 Piston / Head Clearance

=20

My forged pistons are .006" in the hole at TDC and I use a .030" thick =
solid copper head gasket and stock crank at 6200 rpm. When removing the =
head, the piston tops are clean in the squish area and it looks like a =
slight indentation at the ledge of the combustion chamber, probably from =
piston rock when the engine is cold.   =20

=20

On Thu, May 26, 2016 at 3:23 PM, Gregmogdoc@surfnetusa.com =
<Gregmogdoc@surfnetusa.com> wrote:

IN our experience with TR-4, and English Ford Kent
racing engines the safe clearance between the head
and the piston crown is .035".  A TR-4 with billet
rods will just "touch" the head at 6800 rpm with
.026" clearance. It will "hit" the head hard enough
to make an imprint in the piston crown at .029"
I would say that the TR-6 crank probably flexes more
than a TR-4 does at high rpm. You would like to have
a little safety margin, I would think. I would not
run less than .035", maybe even a couple more if the
engine is going to run over 6,000 rpm.


Greg Solow
The Engine Room
Sports Car Specialists
Santa Cruz, CA 95060
831 429-1800



------- Original Message -------
>From    : Charly[mailto:charly@mitchelplumbing.com]
Sent    : 5/25/2016 6:52:35 PM
To      : tr4@wi.rr.com; toodamnfunky@comcast.net
Cc      : fot@autox.team.net
Subject : RE: Re: [Fot] TR6 Piston / Head Clearance

 I tried b u idling a TR6 motor with a pop-up on the
piston on c e. Instead of having the pistons cut
down to zero clearance I left them about .005" high.
It eventually bent the rod and broken it. The
pistons had an imprint of the combustion chamber on
them. I learned that at 6000 rpm's, there is
enough deflection in the crank to let them hit the head.
I believe most head gaskets are .0035" aren't they?
Charly Mitchel
TR6 #44

On Wed 25/05/16 11:31 AM , toodamnfunky@comcast.net sent:
> The rattling is likely piston slap on cold forged
pistons. Did it go
> away when it warmed up and came back on the next
cold start ?jim
>
> -------------------------
> FROM: "Steve Yott"
> TO: "Robert Lang" , "FOT List"
> SENT: Wednesday, May 25, 2016 11:27:27 AM
> SUBJECT: Re: [Fot] TR6 Piston / Head Clearance
> I doubt that your .030 squish would cause the
rattling as you
> describe.  The deflection caused by the crank, rod
and piston in order
> to hit the head at .030 would be way up in the
rpm=E2=80=99s like 8000!
> Did the rattling go away after all the parts warmed
up and oil was
> well disbursed or is it still rattling?  My first
guess would be
> either the engine was not pre-oiled or you have
loose piston pin
> bushings=E2=80=A6.  Were the rods rebuilt with new bushings
fitted to about
> .0003?
> Steve Yott
> FROM: Fot [ mailto:fot-bounces@autox.team.net ] ON
BEHALF OF Robert
> Lang
> SENT: Wednesday, May 25, 2016 11:29 AM
> TO: FOT List
> SUBJECT: Re: [Fot] TR6 Piston / Head Clearance
> Hi,
> Where I was going with the query was this: I had a
late block
> "decked" with the intent of making the deck flat.
The machinist took
> of .032 to accomplish the goal. With a head gasket
installed and the
> head torqued, the clearance in the squish area is .030.
>
> I had initially wanted only about .025 removed, but
we had to shave
> an extra .007 to get rid of the fire ring cuts.
>
> On initial startup, the motor sounded like it might
be "rattling" and
> I'm trying to figure out why.
>
> When I used a stethescope on the block, everything
sounds okay - no
> rapping and the valve train sounds "normal" and
there were no weird
> sounds coming from the crank.
>
> I guess where I'm going with this is: if piston /
head clearance is
> too tight, I'll see some sort of indication on the
piston, right?
>
> TIA for any sage advice.
>
> This is my first experience "decking" a block. I'd
like to get it
> right, I don't have the resources to start a new
block from scratch.
>
> Regards,
>
> Bob Lang
> _______________________________________________
> fot@autox.team.net
>
>  http://www.fot-racing.com
>
> Donate:  http://www.team.net/donate.html
> Archive:  http://www.team.net/archive
> Forums:  http://www.team.net/forums
> Unsubscribe/Manage:
>
http://autox.team.net/mailman/options/fot/toodamnfunky@comcast.net

>
>

_______________________________________________
fot@autox.team.net

 http://www.fot-racing.com

Archive:  http://www.team.net/archive
Forums:  http://www.team.net/forums
http://autox.team.net/mailman/options/fot/gregmogdoc@surfnetusa.com





_______________________________________________
fot@autox.team.net

http://www.fot-racing.com

Archive: http://www.team.net/archive
http://autox.team.net/mailman/options/fot/johnstydo@gmail.com



=20


------=_NextPart_000_002E_01D1B7FC.6FFBF580
        charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<html xmlns:v=3D"urn:schemas-microsoft-com:vml" =
xmlns:o=3D"urn:schemas-microsoft-com:office:office" =
xmlns:w=3D"urn:schemas-microsoft-com:office:word" =
xmlns:m=3D"http://schemas.microsoft.com/office/2004/12/omml"; =
xmlns=3D"http://www.w3.org/TR/REC-html40";>

<head>
<meta http-equiv=3DContent-Type content=3D"text/html; charset=3Dutf-8">
<meta name=3DGenerator content=3D"Microsoft Word 12 (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;}
@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:0in;
        margin-bottom:.0001pt;
        font-size:12.0pt;
        font-family:"Times New Roman","serif";}
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;}
span.EmailStyle17
        {mso-style-type:personal-reply;
        font-family:"Calibri","sans-serif";
        color:#1F497D;}
.MsoChpDefault
        {mso-style-type:export-only;}
@page Section1
        {size:8.5in 11.0in;
        margin:1.0in 1.0in 1.0in 1.0in;}
div.Section1
        {page:Section1;}
-->
</style>
<!--[if gte mso 9]><xml>
 <o:shapedefaults v:ext=3D"edit" spidmax=3D"1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
 <o:shapelayout v:ext=3D"edit">
  <o:idmap v:ext=3D"edit" data=3D"1" />
 </o:shapelayout></xml><![endif]-->
</head>

<body lang=3DEN-US link=3Dblue vlink=3Dpurple>

<div class=3DSection1>

<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Since most of you like to play the =E2=80=9Cdeath with =
pistons=E2=80=9D game
keep in mind one additional factor as you are building your =
engines.=C2=A0 Over the
years I have found crankshafts which were reground and the throws were =
not very
precisely indexed.=C2=A0 When a crank is setup on the grinding machine =
for grinding
rod journals it is set and reset by the number of =
=E2=80=9Cthrows=E2=80=9D=E2=80=A6 on a 4 cylinder
engine the grinder has to be indexed twice and on the 6 cylinder, 3 =
times.=C2=A0 If
the grinder, either the person or the machine is not perfectly accurate =
you
will see variations of TDC for the throws!=C2=A0 I have seen these =
deviations be as
much as .006=E2=80=9D when a good grinder will hold dimensions within =
.001=E2=80=9D.=C2=A0 <o:p></o:p></span></p>

<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p>&nbsp;</o:p></span></p>

<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>So, if you are running close squishes=E2=80=A6. Measure =
TDC on #1 and #2
on the four cylinder and #1, #2 and #3 on the 6 motors=E2=80=A6.. this =
way to can make
sure your throws and TDC=E2=80=99s are spot on.<o:p></o:p></span></p>

<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p>&nbsp;</o:p></span></p>

<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Steve Yott<o:p></o:p></span></p>

<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p>&nbsp;</o:p></span></p>

<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p>&nbsp;</o:p></span></p>

<div style=3D'border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt =
0in 0in 0in'>

<p class=3DMsoNormal><b><span =
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span>=
</b><span
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'> John =
Styduhar
[mailto:johnstydo@gmail.com] <br>
<b>Sent:</b> Thursday, May 26, 2016 4:32 PM<br>
<b>To:</b> Gregmogdoc@surfnetusa.com<br>
<b>Cc:</b> Charly Mitchel; Steve Yott; Jim Gray; Triumph 'Friends of =
Triumph<br>
<b>Subject:</b> Re: [Fot] TR6 Piston / Head =
Clearance<o:p></o:p></span></p>

</div>

<p class=3DMsoNormal><o:p>&nbsp;</o:p></p>

<div>

<div>

<p class=3DMsoNormal>My forged pistons are .006&quot; in the hole at TDC =
and I
use a .030&quot; thick solid copper head gasket and stock crank at 6200 =
rpm.
When removing the head, the piston tops are clean in the squish area and =
it
looks like a slight indentation at the ledge of the combustion chamber,
probably from piston rock when the engine is cold. &nbsp; =
&nbsp;<o:p></o:p></p>

</div>

</div>

<div>

<p class=3DMsoNormal><o:p>&nbsp;</o:p></p>

<div>

<p class=3DMsoNormal>On Thu, May 26, 2016 at 3:23 PM, <a
href=3D"mailto:Gregmogdoc@surfnetusa.com";>Gregmogdoc@surfnetusa.com</a> =
&lt;<a
href=3D"mailto:Gregmogdoc@surfnetusa.com"; =
target=3D"_blank">Gregmogdoc@surfnetusa.com</a>&gt;
wrote:<o:p></o:p></p>

<p class=3DMsoNormal style=3D'margin-bottom:12.0pt'>IN our experience =
with TR-4,
and English Ford Kent<br>
racing engines the safe clearance between the head<br>
and the piston crown is .035&quot;.&nbsp; A TR-4 with billet<br>
rods will just &quot;touch&quot; the head at 6800 rpm with<br>
.026&quot; clearance. It will &quot;hit&quot; the head hard enough<br>
to make an imprint in the piston crown at .029&quot;<br>
I would say that the TR-6 crank probably flexes more<br>
than a TR-4 does at high rpm. You would like to have<br>
a little safety margin, I would think. I would not<br>
run less than .035&quot;, maybe even a couple more if the<br>
engine is going to run over 6,000 rpm.<br>
<br>
<br>
Greg Solow<br>
The Engine Room<br>
Sports Car Specialists<br>
Santa Cruz, CA 95060<br>
831 429-1800<br>
<br>
<br>
<br>
------- Original Message -------<br>
From&nbsp; &nbsp; : Charly[mailto:<a =
href=3D"mailto:charly@mitchelplumbing.com";>charly@mitchelplumbing.com</a>=
]<br>
Sent&nbsp; &nbsp; : 5/25/2016 6:52:35 PM<br>
To&nbsp; &nbsp; &nbsp; : <a =
href=3D"mailto:tr4@wi.rr.com";>tr4@wi.rr.com</a>; <a
href=3D"mailto:toodamnfunky@comcast.net";>toodamnfunky@comcast.net</a><br>=

Cc&nbsp; &nbsp; &nbsp; : <a =
href=3D"mailto:fot@autox.team.net";>fot@autox.team.net</a><br>
Subject : RE: Re: [Fot] TR6 Piston / Head Clearance<br>
<br>
&nbsp;I tried b u idling a TR6 motor with a pop-up on the<br>
piston on c e. Instead of having the pistons cut<br>
down to zero clearance I left them about .005&quot; high.<br>
It eventually bent the rod and broken it. The<br>
pistons had an imprint of the combustion chamber on<br>
them. I learned that at 6000 rpm's, there is<br>
enough deflection in the crank to let them hit the head.<br>
I believe most head gaskets are .0035&quot; aren't they?<br>
Charly Mitchel<br>
TR6 #44<br>
<br>
On Wed 25/05/16 11:31 AM , <a =
href=3D"mailto:toodamnfunky@comcast.net";>toodamnfunky@comcast.net</a>
sent:<br>
&gt; The rattling is likely piston slap on cold forged<br>
pistons. Did it go<br>
&gt; away when it warmed up and came back on the next<br>
cold start ?jim<br>
&gt;<br>
&gt; -------------------------<br>
&gt; FROM: &quot;Steve Yott&quot;<br>
&gt; TO: &quot;Robert Lang&quot; , &quot;FOT List&quot;<br>
&gt; SENT: Wednesday, May 25, 2016 11:27:27 AM<br>
&gt; SUBJECT: Re: [Fot] TR6 Piston / Head Clearance<br>
&gt; I doubt that your .030 squish would cause the<br>
rattling as you<br>
&gt; describe.&nbsp; The deflection caused by the crank, rod<br>
and piston in order<br>
&gt; to hit the head at .030 would be way up in the<br>
rpm=E2=80=99s like 8000!<br>
&gt; Did the rattling go away after all the parts warmed<br>
up and oil was<br>
&gt; well disbursed or is it still rattling?&nbsp; My first<br>
guess would be<br>
&gt; either the engine was not pre-oiled or you have<br>
loose piston pin<br>
&gt; bushings=E2=80=A6.&nbsp; Were the rods rebuilt with new =
bushings<br>
fitted to about<br>
&gt; .0003?<br>
&gt; Steve Yott<br>
&gt; FROM: Fot [ mailto:<a =
href=3D"mailto:fot-bounces@autox.team.net";>fot-bounces@autox.team.net</a>=

] ON<br>
BEHALF OF Robert<br>
&gt; Lang<br>
&gt; SENT: Wednesday, May 25, 2016 11:29 AM<br>
&gt; TO: FOT List<br>
&gt; SUBJECT: Re: [Fot] TR6 Piston / Head Clearance<br>
&gt; Hi,<br>
&gt; Where I was going with the query was this: I had a<br>
late block<br>
&gt; &quot;decked&quot; with the intent of making the deck flat.<br>
The machinist took<br>
&gt; of .032 to accomplish the goal. With a head gasket<br>
installed and the<br>
&gt; head torqued, the clearance in the squish area is .030.<br>
&gt;<br>
&gt; I had initially wanted only about .025 removed, but<br>
we had to shave<br>
&gt; an extra .007 to get rid of the fire ring cuts.<br>
&gt;<br>
&gt; On initial startup, the motor sounded like it might<br>
be &quot;rattling&quot; and<br>
&gt; I'm trying to figure out why.<br>
&gt;<br>
&gt; When I used a stethescope on the block, everything<br>
sounds okay - no<br>
&gt; rapping and the valve train sounds &quot;normal&quot; and<br>
there were no weird<br>
&gt; sounds coming from the crank.<br>
&gt;<br>
&gt; I guess where I'm going with this is: if piston /<br>
head clearance is<br>
&gt; too tight, I'll see some sort of indication on the<br>
piston, right?<br>
&gt;<br>
&gt; TIA for any sage advice.<br>
&gt;<br>
&gt; This is my first experience &quot;decking&quot; a block. I'd<br>
like to get it<br>
&gt; right, I don't have the resources to start a new<br>
block from scratch.<br>
&gt;<br>
&gt; Regards,<br>
&gt;<br>
&gt; Bob Lang<br>
&gt; _______________________________________________<br>
&gt; <a href=3D"mailto:fot@autox.team.net";>fot@autox.team.net</a><br>
&gt;<br>
&gt;&nbsp; <a href=3D"http://www.fot-racing.com"; =
target=3D"_blank">http://www.fot-racing.com</a><br>
&gt;<br>
&gt; Donate:&nbsp; <a href=3D"http://www.team.net/donate.html"; =
target=3D"_blank">http://www.team.net/donate.html</a><br>
&gt; Archive:&nbsp; <a href=3D"http://www.team.net/archive"; =
target=3D"_blank">http://www.team.net/archive</a><br>
&gt; Forums:&nbsp; <a href=3D"http://www.team.net/forums"; =
target=3D"_blank">http://www.team.net/forums</a><br>
&gt; Unsubscribe/Manage:<br>
&gt;<br>
<a =
href=3D"http://autox.team.net/mailman/options/fot/toodamnfunky@comcast.ne=
t"
target=3D"_blank">http://autox.team.net/mailman/options/fot/toodamnfunky@=
comcast.net</a><br>
<br>
&gt;<br>
&gt;<br>
<br>
_______________________________________________<br>
<a href=3D"mailto:fot@autox.team.net";>fot@autox.team.net</a><br>
<br>
&nbsp;<a href=3D"http://www.fot-racing.com"; =
target=3D"_blank">http://www.fot-racing.com</a><br>
<br>
Donate:&nbsp; <a href=3D"http://www.team.net/donate.html"; =
target=3D"_blank">http://www.team.net/donate.html</a><br>
Archive:&nbsp; <a href=3D"http://www.team.net/archive"; =
target=3D"_blank">http://www.team.net/archive</a><br>
Forums:&nbsp; <a href=3D"http://www.team.net/forums"; =
target=3D"_blank">http://www.team.net/forums</a><br>
<a =
href=3D"http://autox.team.net/mailman/options/fot/gregmogdoc@surfnetusa.c=
om"
target=3D"_blank">http://autox.team.net/mailman/options/fot/gregmogdoc@su=
rfnetusa.com</a><br>
<br>
<br>
<br>
<br>
<br>
_______________________________________________<br>
<a href=3D"mailto:fot@autox.team.net";>fot@autox.team.net</a><br>
<br>
<a href=3D"http://www.fot-racing.com"; =
target=3D"_blank">http://www.fot-racing.com</a><br>
<br>
target=3D"_blank">http://www.team.net/donate.html</a><br>
Archive: <a href=3D"http://www.team.net/archive"; =
target=3D"_blank">http://www.team.net/archive</a><br>
Forums: <a href=3D"http://www.team.net/forums"; =
target=3D"_blank">http://www.team.net/forums</a><br>
href=3D"http://autox.team.net/mailman/options/fot/johnstydo@gmail.com";
target=3D"_blank">http://autox.team.net/mailman/options/fot/johnstydo@gma=
il.com</a><br>
<br>
<o:p></o:p></p>

</div>

<p class=3DMsoNormal><o:p>&nbsp;</o:p></p>

</div>

</div>

</body>

</html>

------=_NextPart_000_002E_01D1B7FC.6FFBF580--


--===============6604246436966436090==
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

_______________________________________________
fot@autox.team.net

http://www.fot-racing.com

Archive: http://www.team.net/archive



--===============6604246436966436090==--

<Prev in Thread] Current Thread [Next in Thread>