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Iskenderian racing valve spring kit for the TR-2-3-4 shows a seat pressure
of 100 lbs.
On Wed, Sep 16, 2015 at 6:38 AM, MadMarx <tr4racing@googlemail.com> wrote:
> Marcel,
>
>
>
> I use 55 kg seat pressure.
>
>
>
> Cheers
>
> Chris
>
>
>
> *Von:* Fot [mailto:fot-bounces@autox.team.net] *Im Auftrag von *Marcel
> Van Mulders
> *Gesendet:* Mittwoch, 16. September 2015 12:22
> *An:* 'Michael Porter'
> *Cc:* fot@autox.team.net
> *Betreff:* Re: [Fot] FW: TR6 Cannon Intake Manifold
>
>
>
>
>
>
> Thanks Keith and Michael. About valve springs and seat pressure : it's a
> question about
>
> keeping the valve train parts together but also to avoid that the valves
> bounce off the seats after (the first) landing. I suppose this valve bounce
> is not so clearly reflected in the power dropping at high revs, . On
> youtube are very interesting high speed cam video's on valve bounce, spring
> surge...
> ------------------------------
>
> *Van:* Michael Porter [mailto:mdporter@dfn.com <mdporter@dfn.com>]
> *Verzonden:* woensdag 16 september 2015 10:57
> *Aan:* Van Mulders Marcel
> *Onderwerp:* Re: [Fot] FW: TR6 Cannon Intake Manifold
>
> On 9/16/2015 2:18 AM, Van Mulders Marcel wrote:
>
> Thanks to the Fot members for their reactions : most are warnings that
> triple 45 Webers may be too big on a TR6 engine. But it is a race engine
> (2720cc) and the owner has already bought 3 good secondhand 45 Webers with
> identical progression holes : 36mm main venturi's seem to be a reasonable
> starting point in this case? If necessary, he can go down to 34mm in 45
> Webers.
>
> I've seen TR6 racecars with 45 Webers and I wonder if the Cannon
> manifold, with 40mm diameter bores on the carburetor side, can be reamed to
> 45mm?
>
> Another question : the valve seat pressure on my TR4A racecar is 35 kgs/77
> lbs. I've also a cylinderhead with only 25 kgs/55lbs seat pressure. The
> springs on both cylinderheads are 5.25kg/mm (290lbs/").
>
> Do you think 25kgs seat pressure is enough?
>
>
>
>
> On fitting 45s to the 40DCOE manifold, yes, I think there's enough meat to
> match the manifold to the carburetor exit. It would mean increasing the
> radius by 2.5mm (~ 0.100"), but I wouldn't do it until 45mm soft mounts can
> be obtained--if only 40mm are available, then it's a waste of time and
> money. I would recommend that the shop doing the machining find a suitable
> diameter end mill with a 10-15 deg. taper, just to minimize the finish work
> required and to make a smooth transition to the smaller manifold bore.
>
> I don't actually understand the complaints about 45DCOEs being too big for
> a moderately-sized six-cylinder. For all-around use on the street, 40s
> would be more than enough, but on the track, 45s are fine. In fact, I
> recall 45s with 38mm main venturis being used commonly, but mostly on
> engines tuned to 7200 rpm or so. The advantage of Webers is that they have
> lots of spares to tune to carburetor to the application, although the
> expense of having such spares on hand for tuning is rarely part of the
> equation.
>
> As for valve seat pressures, they're not as important as having just
> enough spring pressure to keep the follower tracking the cam profile. For
> normally-aspirated engines, anyway (seat pressures become more of an issue
> with supercharged engines, when too much boost can push a valve off its
> seat if the static spring pressure is too low). The lower the combined
> weight of the valve train, the lower the spring pressure required. The
> steeper the ramps on the cam, the greater the spring pressure required to
> overcome the acceleration of the valve train parts. So, it's kind of a
> balancing act, and one that can usually only be handled on the dyno, while
> looking for power drops at high rpm due to valve float.
>
>
> Cheers.
>
> --
>
>
>
>
>
> Michael Porter
>
> Roswell, NM
>
>
>
>
>
> Never let anyone drive you crazy when you know it's within walking
> distance....
>
>
> _______________________________________________
> 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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> Unsubscribe/Manage:
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>
>
>
>
--047d7bfd066858691a051fdc5292
Content-Transfer-Encoding: quoted-printable
<div dir=3D"ltr"><div class=3D"gmail_default" style=3D"font-size:small">Isk=
enderian racing valve spring kit for the TR-2-3-4 shows a seat pressure of =
100 lbs.=C2=A0</div></div><div class=3D"gmail_extra"><br><div class=3D"gmai=
l_quote">On Wed, Sep 16, 2015 at 6:38 AM, MadMarx <span dir=3D"ltr"><<a =
href=3D"mailto:tr4racing@googlemail.com"; target=3D"_blank">tr4racing@google=
mail.com</a>></span> wrote:<br><blockquote class=3D"gmail_quote" style=
=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgc=
olor=3D"white" lang=3D"DE" link=3D"blue" vlink=3D"purple"><div><p class=3D"=
MsoNormal"><span style=3D"font-size:10.0pt;font-family:"Verdana",=
"sans-serif";color:#1f497d">Marcel,<u></u><u></u></span></p><p cl=
ass=3D"MsoNormal"><span style=3D"font-size:10.0pt;font-family:"Verdana=
","sans-serif";color:#1f497d"><u></u>=C2=A0<u></u></span></p=
><p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font=
-family:"Verdana","sans-serif";color:#1f497d">I use 55 =
kg seat pressure.<u></u><u></u></span></p><p class=3D"MsoNormal"><span lang=
=3D"EN-US" style=3D"font-size:10.0pt;font-family:"Verdana","=
sans-serif";color:#1f497d"><u></u>=C2=A0<u></u></span></p><p class=3D"=
MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-family:"=
;Verdana","sans-serif";color:#1f497d">Cheers<u></u><u></u></=
span></p><p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.=
0pt;font-family:"Verdana","sans-serif";color:#1f497d">C=
hris<u></u><u></u></span></p><p class=3D"MsoNormal"><span lang=3D"EN-US" st=
yle=3D"font-size:10.0pt;font-family:"Verdana","sans-serif&qu=
ot;;color:#1f497d"><u></u>=C2=A0<u></u></span></p><div><div style=3D"border=
:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0cm 0cm 0cm"><p class=3D=
"MsoNormal"><b><span style=3D"font-size:10.0pt;font-family:"Tahoma&quo=
t;,"sans-serif";color:windowtext">Von:</span></b><span style=3D"f=
ont-size:10.0pt;font-family:"Tahoma","sans-serif";color=
:windowtext"> Fot [mailto:<a href=3D"mailto:fot-bounces@autox.team.net"; tar=
get=3D"_blank">fot-bounces@autox.team.net</a>] <b>Im Auftrag von </b>Marcel=
Van Mulders<br><b>Gesendet:</b> Mittwoch, 16. September 2015 12:22<br><b>A=
n:</b> 'Michael Porter'<br><b>Cc:</b> <a href=3D"mailto:fot@autox.t=
eam.net" target=3D"_blank">fot@autox.team.net</a><br><b>Betreff:</b> Re: [F=
ot] FW: TR6 Cannon Intake Manifold<u></u><u></u></span></p></div></div><div=
><div class=3D"h5"><p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p><p class=
=3D"MsoNormal">=C2=A0<u></u><u></u></p><div><p class=3D"MsoNormal"><span st=
yle=3D"font-size:10.0pt;font-family:"Arial","sans-serif"=
;;color:blue">Thanks=C2=A0Keith=C2=A0and=C2=A0Michael.=C2=A0About=C2=A0valv=
e=C2=A0springs=C2=A0and=C2=A0seat=C2=A0pressure=C2=A0:=C2=A0it's=C2=A0a=
=C2=A0question=C2=A0about</span><u></u><u></u></p></div><div><p class=3D"Ms=
oNormal"><span style=3D"font-size:10.0pt;font-family:"Arial",&quo=
t;sans-serif";color:blue">keeping=C2=A0the=C2=A0valve=C2=A0train=C2=A0=
parts together but also to avoid that the valves bounce off the seats after=
(the first) landing. I suppose this valve bounce is not so clearly reflect=
ed in the power=C2=A0 dropping at high revs, . On youtube are very interest=
ing=C2=A0high speed cam video's on valve bounce, spring surge...</span>=
<u></u><u></u></p></div><div class=3D"MsoNormal" align=3D"center" style=3D"=
text-align:center"><span lang=3D"NL"><hr size=3D"2" width=3D"100%" align=3D=
"center"></span></div><p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"=
><b><span lang=3D"NL" style=3D"font-size:10.0pt;font-family:"Tahoma&qu=
ot;,"sans-serif"">Van:</span></b><span lang=3D"NL" style=3D"font-=
size:10.0pt;font-family:"Tahoma","sans-serif""> Michael=
Porter [<a href=3D"mailto:mdporter@dfn.com"; target=3D"_blank">mailto:mdpor=
ter@dfn.com</a>] <br><b>Verzonden:</b> woensdag 16 september 2015 10:57<br>=
<b>Aan:</b> Van Mulders Marcel<br><b>Onderwerp:</b> Re: [Fot] FW: TR6 Canno=
n Intake Manifold</span><span lang=3D"NL"><u></u><u></u></span></p><div><p =
class=3D"MsoNormal">On 9/16/2015 2:18 AM, Van Mulders Marcel wrote:<u></u><=
u></u></p></div><blockquote style=3D"margin-top:5.0pt;margin-bottom:5.0pt">=
<p class=3D"MsoNormal"><span style=3D"font-size:10.0pt;font-family:"Ar=
ial","sans-serif";color:blue">Thanks to the Fot members for =
their reactions : most are=C2=A0warnings that triple 45 Webers may be too b=
ig on a TR6 engine. But it is a race engine (2720cc) and=C2=A0the owner has=
already bought 3=C2=A0good secondhand 45 Webers with identical progression=
holes :=C2=A036mm=C2=A0main venturi's=C2=A0seem=C2=A0 to be=C2=A0a rea=
sonable starting point in this case? If necessary, he can go down to 34mm i=
n 45 Webers.</span><u></u><u></u></p><p class=3D"MsoNormal"><span style=3D"=
font-size:10.0pt;font-family:"Arial","sans-serif";color=
:blue">=C2=A0I've seen TR6 racecars with 45 Webers and I wonder if the =
Cannon manifold, with=C2=A040mm diameter bores on the carburetor side,=C2=
=A0can be reamed to 45mm? </span><u></u><u></u></p><p class=3D"MsoNormal"><=
span style=3D"font-size:10.0pt;font-family:"Arial","sans-ser=
if";color:blue">Another question : the valve=C2=A0seat pressure on my =
TR4A racecar is 35 kgs/77 lbs. I've also a cylinderhead with only 25 kg=
s/55lbs seat pressure. The springs on both cylinderheads are 5.25kg/mm (290=
lbs/").</span><u></u><u></u></p><p class=3D"MsoNormal"><span style=3D"=
font-size:10.0pt;font-family:"Arial","sans-serif";color=
:blue">Do you think 25kgs seat pressure is enough?</span><u></u><u></u></p>=
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p></blockquote><p class=3D"Mso=
Normal"><br>On fitting 45s to the 40DCOE manifold, yes, I think there's=
enough meat to match the manifold to the carburetor exit.=C2=A0 It would m=
ean increasing the radius by 2.5mm (~ 0.100"), but I wouldn't do i=
t until 45mm soft mounts can be obtained--if only 40mm are available, then =
it's a waste of time and money.=C2=A0 I would recommend that the shop d=
oing the machining find a suitable diameter end mill with a 10-15 deg. tape=
r, just to minimize the finish work required and to make a smooth transitio=
n to the smaller manifold bore.<br><br>I don't actually understand the =
complaints about 45DCOEs being too big for a moderately-sized six-cylinder.=
=C2=A0 For all-around use on the street, 40s would be more than enough, but=
on the track, 45s are fine.=C2=A0 In fact, I recall 45s with 38mm main ven=
turis being used commonly, but mostly on engines tuned to 7200 rpm or so.=
=C2=A0 The advantage of Webers is that they have lots of spares to tune to =
carburetor to the application, although the expense of having such spares o=
n hand for tuning is rarely part of the equation.<br><br>As for valve seat =
pressures, they're not as important as having just enough spring pressu=
re to keep the follower tracking the cam profile.=C2=A0 For normally-aspira=
ted engines, anyway (seat pressures become more of an issue with supercharg=
ed engines, when too much boost can push a valve off its seat if the static=
spring pressure is too low).=C2=A0 The lower the combined weight of the va=
lve train, the lower the spring pressure required.=C2=A0 The steeper the ra=
mps on the cam, the greater the spring pressure required to overcome the ac=
celeration of the valve train parts.=C2=A0 So, it's kind of a balancing=
act, and one that can usually only be handled on the dyno, while looking f=
or power drops at high rpm due to valve float.<br><br><br>Cheers.<br><br><u=
></u><u></u></p><pre>-- <u></u><u></u></pre><pre><u></u>=C2=A0<u></u></pre>=
<pre><u></u>=C2=A0<u></u></pre><pre>Michael Porter<u></u><u></u></pre><pre>=
Roswell, NM<u></u><u></u></pre><pre><u></u>=C2=A0<u></u></pre><pre><u></u>=
=C2=A0<u></u></pre><pre>Never let anyone drive you crazy when you know it&#=
39;s within walking distance....<u></u><u></u></pre></div></div></div></div=
><br>_______________________________________________<br>
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<br></blockquote></div><br></div>
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