This is a multi-part message in MIME format.
--===============8798412007460391968==
boundary="----=_NextPart_000_00AE_01D19F1B.266435D0"
This is a multi-part message in MIME format.
------=_NextPart_000_00AE_01D19F1B.266435D0
charset="utf-8"
Content-Transfer-Encoding: quoted-printable
>>>Even with the original 1.67" intake valves, a 0.010 deck height and a =
0.040 thick head gasket, I don't comprehend where a 0.070" minimum valve =
to piston clearance is possible.<<<
I don=E2=80=99t know to what extent you are versed in the engine, but =
I=E2=80=99ll put this out there and use as you see needed (no insult to =
your knowledge intended in my comments).
The valves are recessed in the combustion chamber so the total of the =
deck height and the gasket in and of themselves do not determine the =
piston to valve clearance (if in fact that is what you assumed???). =
Probably the best way to determine the actual clearance is to:
A. If the head is not installed remove a larger intake valve spring. Set =
the head on a flat surface with the valve down, then set and zero a dial =
indicator on the valve stem tip. Push the valve up and measure the =
distance. Add the stated deck and gasket thickness and that gives you =
the clearance. Unless you check them all there is a likelihood that not =
all will be the same. Casting accuracy and seat recession from wear or =
prior valve jobs can change the numbers. But, hopefully the others will =
be =E2=80=9Cclose.=E2=80=9D
B. If the head is installed you can bring the piston to TDC, remove the =
valve spring and do similar. There is the likelihood that carbon =
build-up will give a lower number (but is the actual functional =
clearance). Also do not add in the deck height or the gasket thickness =
as they are already present. DO NOT crank the engine while doing this or =
you can drop or bend a valve. A narrow magnet may be required to pull =
the valve back up. Narrow rope can be fed into the chamber through the =
spark plug hole to support the valve while the spring is reinstalled.=20
Remember this gives you the total distance until a valve hits a piston =
so the required clearance (0.070?) will have to be subtracted from the =
total number. Also, Cams ramp up and down the lobe and may not be at =
its highest lift when the piston is at TDC. Therefore it is possible =
that the cam lift can be greater than the minimal clearance because the =
piston is not at TDC (or near enough) when it occurs.
People have used talc powder on clay on top of the piston then cycled =
the engine through a few revolutions, and measured (Calipers) the height =
of the clay. Thus getting an =E2=80=9Cactive=E2=80=9D rather than a =
theoretical valve clearance. This requires assembly/unassembly to =
measure and a very light spring so as not to collapse the lifter (if =
hydraulic). Also consider that advancing/retarding the cam from the =
centerline will also alter these =E2=80=9Cactive=E2=80=9D clearances. =
Lastly, the valve stem to rocker tip clearance (mechanical lifter =
=E2=80=93 if used) will create additional clearance.
I hope there is something you can glean from this and I haven=E2=80=99t =
created any confusion.=20
From: Rob Hogan via Tigers=20
Sent: Friday, April 22, 2016 9:17 PM
To: Tiger's List=20
Subject: [Tigers] Stock 260 Engine Maximum Cam Lift
Does anyone have experience using a hydraulic lifter camshaft with a =
lift greater than 0.440 (Clymer book page 41 maximum) in the flat top =
piston stock 260 cu. in. engine?
Even with the original 1.67" intake valves, a 0.010 deck height and a =
0.040 thick head gasket, I don't comprehend where a 0.070" minimum valve =
to piston clearance is possible.
=20
Rob Hogan
------=_NextPart_000_00AE_01D19F1B.266435D0
charset="utf-8"
Content-Transfer-Encoding: quoted-printable
<HTML><HEAD></HEAD>
<BODY dir=3Dltr>
<DIV dir=3Dltr>
<DIV style=3D"FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000">
<DIV><FONT face=3DVerdana><FONT style=3D"FONT-SIZE: =
18pt"><EM>>>>Even with=20
the original 1.67" intake valves, a 0.010 deck height and a 0.040 thick =
head=20
gasket, I don't comprehend where a 0.070" minimum valve to piston =
clearance is=20
possible.<<<</EM></FONT></FONT></DIV>
<DIV> </DIV>
<DIV>I don=E2=80=99t know to what extent you are versed in the engine, =
but I=E2=80=99ll put this=20
out there and use as you see needed (no insult to your knowledge =
intended in my=20
comments).</DIV>
<DIV> </DIV>
<DIV>The valves are recessed in the combustion chamber so the total of =
the deck=20
height and the gasket in and of themselves do not determine the piston =
to valve=20
clearance (if in fact that is what you assumed???). Probably the best =
way to=20
determine the actual clearance is to:</DIV>
<DIV> </DIV>
<DIV>A. If the head is not installed remove a larger intake valve =
spring. Set=20
the head on a flat surface with the valve down, then set and zero a dial =
indicator on the valve stem tip. Push the valve up and measure the=20
distance. Add the stated deck and gasket thickness and that =
gives=20
you the clearance. Unless you check them all there is a likelihood that =
not all=20
will be the same. Casting accuracy and seat recession from wear or prior =
valve=20
jobs can change the numbers. But, hopefully the others will be =
=E2=80=9Cclose.=E2=80=9D</DIV>
<DIV> </DIV>
<DIV>B. If the head is installed you can bring the piston to TDC, remove =
the=20
valve spring and do similar. There is the likelihood that carbon =
build-up=20
will give a lower number (but is the actual functional clearance). Also =
do not=20
add in the deck height or the gasket thickness as they are already =
present. DO=20
NOT crank the engine while doing this or you can drop or bend a valve. A =
narrow=20
magnet may be required to pull the valve back up. Narrow rope can be fed =
into=20
the chamber through the spark plug hole to support the valve while the =
spring is=20
reinstalled. </DIV>
<DIV> </DIV>
<DIV>Remember this gives you the total distance until a valve hits a =
piston so=20
the required clearance (0.070?) will have to be subtracted from the =
total=20
number. Also, Cams ramp up and down the lobe and may not be at its =
highest=20
lift when the piston is at TDC. Therefore it is possible that the =
cam lift=20
can be greater than the minimal clearance because the piston is not at =
TDC (or=20
near enough) when it occurs.</DIV>
<DIV> </DIV>
<DIV> People have used talc powder on clay on top of the piston =
then=20
cycled the engine through a few revolutions, and measured (Calipers) the =
height=20
of the clay. Thus getting an =E2=80=9Cactive=E2=80=9D rather than a =
theoretical valve=20
clearance. This requires assembly/unassembly to measure and a very =
light=20
spring so as not to collapse the lifter (if hydraulic). Also consider =
that=20
advancing/retarding the cam from the centerline will also alter these =
=E2=80=9Cactive=E2=80=9D=20
clearances. Lastly, the valve stem to rocker tip clearance (mechanical =
lifter =E2=80=93=20
if used) will create additional clearance.</DIV>
<DIV> </DIV>
<DIV>I hope there is something you can glean from this and I =
haven=E2=80=99t created any=20
confusion. </DIV>
<DIV=20
style=3D'FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: =
"Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; =
DISPLAY: inline'>
<DIV style=3D"FONT: 10pt tahoma">
<DIV> </DIV>
<DIV style=3D"BACKGROUND: #f5f5f5">
<DIV style=3D"font-color: black"><B>From:</B> <A =
title=3Dtigers@autox.team.net=20
href=3D"mailto:tigers@autox.team.net";>Rob Hogan via Tigers</A> </DIV>
<DIV><B>Sent:</B> Friday, April 22, 2016 9:17 PM</DIV>
<DIV><B>To:</B> <A title=3Dtigers@autox.team.net=20
href=3D"mailto:tigers@autox.team.net";>Tiger's List</A> </DIV>
<DIV><B>Subject:</B> [Tigers] Stock 260 Engine Maximum Cam=20
Lift</DIV></DIV></DIV>
<DIV> </DIV></DIV>
<DIV=20
style=3D'FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: =
"Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; =
DISPLAY: inline'>
<DIV dir=3Dltr>
<DIV class=3Dgmail_default=20
style=3D"FONT-SIZE: large; FONT-FAMILY: verdana,sans-serif">Does anyone =
have=20
experience using a hydraulic lifter camshaft with a lift greater than =
0.440=20
(Clymer book page 41 maximum) in the flat top piston stock 260 cu. in.=20
engine?</DIV>
<DIV class=3Dgmail_default=20
style=3D"FONT-SIZE: large; FONT-FAMILY: verdana,sans-serif"> </DIV>
<DIV class=3Dgmail_default=20
style=3D"FONT-SIZE: large; FONT-FAMILY: verdana,sans-serif">Even with =
the original=20
1.67" intake valves, a 0.010 deck height and a 0.040 thick head gasket, =
I don't=20
comprehend where a 0.070" minimum valve to piston clearance is =
possible.</DIV>
<DIV class=3Dgmail_default=20
style=3D"FONT-SIZE: large; FONT-FAMILY: verdana,sans-serif"> </DIV>
<DIV class=3Dgmail_default=20
style=3D"FONT-SIZE: large; FONT-FAMILY: verdana,sans-serif"> </DIV>
<DIV>
<DIV class=3Dgmail_signature>
<DIV dir=3Dltr>Rob=20
Hogan<BR></DIV></DIV></DIV></DIV></DIV></DIV></DIV></BODY></HTML>
------=_NextPart_000_00AE_01D19F1B.266435D0--
--===============8798412007460391968==
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
_______________________________________________
tigers@autox.team.net
Archive: http://www.team.net/archive
Unsubscribe: http://autox.team.net/mailman/options/tigers/mharc@autox.team.net
--===============8798412007460391968==--
|