--===============4462883602116531961==
--001a114034043ce96e0533d5d6a0
Content-Transfer-Encoding: quoted-printable
This discussion has been about flat top pistons to this point Tr6 and TR4
but what about our lonely little GT6s? Is it possible to get some decent
compression with flat tops in a GT6? By decent I guess I'm saying I would
like to see 11.5:1 or more.. To date everyone has suggested using dome tops
with all sorts of different configurations but if it were a simple matter
of raising the flat tops up into the combustion chamber it would make
matters much simpler. I know the heads are basically a TR6 head that has
been milled down about 1/4 of an inch so most of what would have been used
to shrink the combustion chamber size is already gone. I also know that
with the TR6 head it's possible to "Flycut" or "Counterbore" into the head
for the piston to stick up quite a bit. Will this work with a GT6 head?
Thanks. P.J.
On Fri, May 27, 2016 at 9:45 AM, Steve Yott <tr4@wi.rr.com> wrote:
> Since most of you like to play the =E2=80=9Cdeath with pistons=E2=80=9D g=
ame 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=9Cthrow=
s=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 perfect=
ly
> accurate you will see variations of TDC for the throws! I have seen thes=
e
> deviations be as much as .006=E2=80=9D when a good grinder will hold dime=
nsions
> within .001=E2=80=9D.
>
>
>
> 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 ca=
n make
> sure your throws and TDC=E2=80=99s are spot on.
>
>
>
> Steve Yott
>
>
>
>
>
> *From:* John Styduhar [mailto:johnstydo@gmail.com]
> *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
>
>
>
> 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.
>
>
>
> 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
>
> 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/gregmogdoc@surfnetusa.com
>
>
>
>
>
> _______________________________________________
> fot@autox.team.net
>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/archive
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>
>
>
> _______________________________________________
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>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
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>
>
>
>
--001a114034043ce96e0533d5d6a0
Content-Transfer-Encoding: quoted-printable
<div dir=3D"ltr"><div>This discussion has been about flat top pistons to th=
is point Tr6 and TR4 but what about our lonely little GT6s? Is it possible =
to get some decent compression with flat tops in a GT6?=C2=A0 By decent I g=
uess I'm saying I =C2=A0would like to see 11.5:1 or more.. To date ever=
yone has suggested using dome tops with all sorts of different configuratio=
ns but if it were a simple matter of raising the flat tops up into the comb=
ustion=C2=A0chamber it would make matters much simpler. I know the heads ar=
e basically a TR6 head that has been milled down about 1/4 of an inch so mo=
st of what would have been used to shrink the combustion chamber size =C2=
=A0is already gone. I also know that with the TR6 head it's possible to=
"Flycut" or "Counterbore" into the head for the piston=
to stick up quite a bit. Will this work with a GT6 head?</div><div>=C2=A0 =
Thanks. P.J.</div></div><div class=3D"gmail_extra"><br><div class=3D"gmail_=
quote">On Fri, May 27, 2016 at 9:45 AM, Steve Yott <span dir=3D"ltr"><<a=
href=3D"mailto:tr4@wi.rr.com"; target=3D"_blank">tr4@wi.rr.com</a>></spa=
n> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;b=
order-left:1px #ccc solid;padding-left:1ex">
<div lang=3D"EN-US" vlink=3D"purple" link=3D"blue">
<div>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125);font-family:&quo=
t;Calibri","sans-serif";font-size:11pt">Since most of you li=
ke 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 deviatio=
ns be as
much as .006=E2=80=9D when a good grinder will hold dimensions within .001=
=E2=80=9D.=C2=A0 <u></u><u></u></span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125);font-family:&quo=
t;Calibri","sans-serif";font-size:11pt"><u></u>=C2=A0<u></u>=
</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125);font-family:&quo=
t;Calibri","sans-serif";font-size:11pt">So, if you are runni=
ng 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.<u></u><u></u></span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125);font-family:&quo=
t;Calibri","sans-serif";font-size:11pt"><u></u>=C2=A0<u></u>=
</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125);font-family:&quo=
t;Calibri","sans-serif";font-size:11pt">Steve Yott<u></u><u>=
</u></span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125);font-family:&quo=
t;Calibri","sans-serif";font-size:11pt"><u></u>=C2=A0<u></u>=
</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125);font-family:&quo=
t;Calibri","sans-serif";font-size:11pt"><u></u>=C2=A0<u></u>=
</span></p>
<div style=3D"border-width:1pt medium medium;border-style:solid none none;b=
order-color:rgb(181,196,223) currentColor currentColor;padding:3pt 0in 0in"=
>
<p class=3D"MsoNormal"><b><span style=3D"font-family:"Tahoma",&qu=
ot;sans-serif";font-size:10pt">From:</span></b><span style=3D"font-fam=
ily:"Tahoma","sans-serif";font-size:10pt"> John Styduha=
r
[mailto:<a href=3D"mailto:johnstydo@gmail.com"; target=3D"_blank">johnstydo@=
gmail.com</a>] <br>
<b>Sent:</b> Thursday, May 26, 2016 4:32 PM<br>
<b>To:</b> <a href=3D"mailto:Gregmogdoc@surfnetusa.com"; target=3D"_blank">G=
regmogdoc@surfnetusa.com</a><br>
<b>Cc:</b> Charly Mitchel; Steve Yott; Jim Gray; Triumph 'Friends of Tr=
iumph<br>
<b>Subject:</b> Re: [Fot] TR6 Piston / Head Clearance<u></u><u></u></span><=
/p>
</div>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<div>
<div>
<p class=3D"MsoNormal">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. =C2=A0 =C2=A0<u></u><u><=
/u></p>
</div>
</div>
<div>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<div>
<p class=3D"MsoNormal">On Thu, May 26, 2016 at 3:23 PM, <a href=3D"mailto:G=
regmogdoc@surfnetusa.com" target=3D"_blank">Gregmogdoc@surfnetusa.com</a> &=
lt;<a href=3D"mailto:Gregmogdoc@surfnetusa.com"; target=3D"_blank">Gregmogdo=
c@surfnetusa.com</a>>
wrote:<u></u><u></u></p>
<p class=3D"MsoNormal" style=3D"margin-bottom:12pt">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".=C2=A0 A TR-4 with billet<br>
rods will just "touch" the head at 6800 rpm with<br>
.026" clearance. It will "hit" the head hard enough<br>
to make an imprint in the piston crown at .029"<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", 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=C2=A0 =C2=A0 : Charly[mailto:<a href=3D"mailto:charly@mitchelplumbing.=
com" target=3D"_blank">charly@mitchelplumbing.com</a>]<br>
Sent=C2=A0 =C2=A0 : 5/25/2016 6:52:35 PM<br>
To=C2=A0 =C2=A0 =C2=A0 : <a href=3D"mailto:tr4@wi.rr.com"; target=3D"_blank"=
>tr4@wi.rr.com</a>; <a href=3D"mailto:toodamnfunky@comcast.net"; target=3D"_=
blank">toodamnfunky@comcast.net</a><br>
Cc=C2=A0 =C2=A0 =C2=A0 : <a href=3D"mailto:fot@autox.team.net"; target=3D"_b=
lank">fot@autox.team.net</a><br>
Subject : RE: Re: [Fot] TR6 Piston / Head Clearance<br>
<br>
=C2=A0I 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" 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" 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"; targ=
et=3D"_blank">toodamnfunky@comcast.net</a>
sent:<br>
> The rattling is likely piston slap on cold forged<br>
pistons. Did it go<br>
> away when it warmed up and came back on the next<br>
cold start ?jim<br>
><br>
> -------------------------<br>
> FROM: "Steve Yott"<br>
> TO: "Robert Lang" , "FOT List"<br>
> SENT: Wednesday, May 25, 2016 11:27:27 AM<br>
> SUBJECT: Re: [Fot] TR6 Piston / Head Clearance<br>
> I doubt that your .030 squish would cause the<br>
rattling as you<br>
> describe.=C2=A0 The deflection caused by the crank, rod<br>
and piston in order<br>
> to hit the head at .030 would be way up in the<br>
rpm=E2=80=99s like 8000!<br>
> Did the rattling go away after all the parts warmed<br>
up and oil was<br>
> well disbursed or is it still rattling?=C2=A0 My first<br>
guess would be<br>
> either the engine was not pre-oiled or you have<br>
loose piston pin<br>
> bushings=E2=80=A6.=C2=A0 Were the rods rebuilt with new bushings<br>
fitted to about<br>
> .0003?<br>
> Steve Yott<br>
> FROM: Fot [ mailto:<a href=3D"mailto:fot-bounces@autox.team.net"; targe=
t=3D"_blank">fot-bounces@autox.team.net</a>
] ON<br>
BEHALF OF Robert<br>
> Lang<br>
> SENT: Wednesday, May 25, 2016 11:29 AM<br>
> TO: FOT List<br>
> SUBJECT: Re: [Fot] TR6 Piston / Head Clearance<br>
> Hi,<br>
> Where I was going with the query was this: I had a<br>
late block<br>
> "decked" with the intent of making the deck flat.<br>
The machinist took<br>
> of .032 to accomplish the goal. With a head gasket<br>
installed and the<br>
> head torqued, the clearance in the squish area is .030.<br>
><br>
> I had initially wanted only about .025 removed, but<br>
we had to shave<br>
> an extra .007 to get rid of the fire ring cuts.<br>
><br>
> On initial startup, the motor sounded like it might<br>
be "rattling" and<br>
> I'm trying to figure out why.<br>
><br>
> When I used a stethescope on the block, everything<br>
sounds okay - no<br>
> rapping and the valve train sounds "normal" and<br>
there were no weird<br>
> sounds coming from the crank.<br>
><br>
> I guess where I'm going with this is: if piston /<br>
head clearance is<br>
> too tight, I'll see some sort of indication on the<br>
piston, right?<br>
><br>
> TIA for any sage advice.<br>
><br>
> This is my first experience "decking" a block. I'd<br>
like to get it<br>
> right, I don't have the resources to start a new<br>
block from scratch.<br>
><br>
> Regards,<br>
><br>
> Bob Lang<br>
> _______________________________________________<br>
> <a href=3D"mailto:fot@autox.team.net"; target=3D"_blank">fot@autox.team=
.net</a><br>
><br>
>=C2=A0 <a href=3D"http://www.fot-racing.com"; target=3D"_blank">http://w=
ww.fot-racing.com</a><br>
><br>
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y@comcast.net</a><br>
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><br>
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<a href=3D"mailto:fot@autox.team.net"; target=3D"_blank">fot@autox.team.net<=
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<br></blockquote></div><br></div>
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fot@autox.team.net
http://www.fot-racing.com
Archive: http://www.team.net/archive
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