--===============5657152862949134756==
boundary="Apple-Mail=_C1F52775-A676-4FF9-80D0-6A7E242FA4D8"
--Apple-Mail=_C1F52775-A676-4FF9-80D0-6A7E242FA4D8
Content-Transfer-Encoding: quoted-printable
charset=utf-8
Maercel, I=E2=80=99m puzzled. Are you referring to the lobe separation =
angle, or to the overlap between the intake valve opening before TDC and =
the exhaust valve closing after TDC on the same revolution? Unless =
I=E2=80=99m reading them wrong, I=E2=80=99ve looked at some pretty =
radical cam specs and the opening/closing overlap does not approach 110 =
degrees, more like 50 degrees on a really aggressive cam, but the lobe =
separation angle is about 104 degrees on the cam I have in the car and =
107 on the cam I=E2=80=99m putting in another engine.
On May 2, 2020, at 4:30 PM, van.mulders.marcel--- via Fot =
<fot@autox.team.net> wrote:
Hallo Chris,
of course the cylinderhead has to be repaired. I think the man who has =
put the big valves in it, has taken too much risks : the valve seats =
(the rings that are pressed into the cyl head) are small where they do =
meet, and maybe the seats are distorted a bit because of this, but I =
don't know for sure, I will see when pulling the head. I know one =
cannot change the valve clearance too much, but maybe 0.05mm more valve =
lash is ok and it will reduce the valve overlap. I believe 110=C2=B0 =
overlap is a lot, even for a racecamshaft. Any idea's someone about =
that? The compression test with increased valve lash is much higher than =
with the recommended valve lash : I wonder if it is making any sense at =
all to check the compression of a race engine without increasing the =
valve lash : with the normal clearances, the inlet valve is closing =
when the piston has already travelled a lot upwards, hence the big =
difference between the compression test results with normal and with =
increased valve lash. So I think, if you want to test the compression, =
you have to increase the valve lash firstly(at least when the engine has =
a race camshaft).
Marcel
Verzonden: Zaterdag 2 mei 2020 21:29:59
Onderwerp: Re: [Fot] Valve overlap and compression test
Hello Marcel,
=20
Your engine has leaking valves.
It won=E2=80=99t get better from changing measurement procedures.
Maybe the seat is rough, or the valves bent, or offset .
Something to make sure about.
=20
Enlarging the valve leash could result in hammering everything dead in =
the valve train.
=20
Cheers
Chris
=20
Von: Fot <fot-bounces@autox.team.net =
van.mulders.marcel--- via Fot
Gesendet: Samstag, 2. Mai 2020 14:43
Betreff: [Fot] Valve overlap and compression test
=20
A leaking test on my TR6 engine is showing a leaking exhaust valve on =
cyl no 1 (48% on the gauge of the device) and a leaking inlet valve on =
cyl no 2 (75%). Compression on cyl no1 is 9.5 bar and on cyl 2 it is 8 =
bar. The compression on the other cylinders is between 12 and 13.5 bar. =
This is with a race cam with a valve overlap of 110=C2=B0 (320-F grind). =
Because of the high overlap, the piston has risen a lot before the inlet =
valve is closed, so I did the compression test again, but with a valve =
lash of 2.5mm/0.1" : compression went from 9.5 bar to 14.5 on cyl no 1 =
and from 8 bar to 15 on cyl no 2. With this valve lash, the compression =
on the other cylinders went up to 16 - 18.5 bar. Of course, when the =
engine is running at high rpm, a lot of valve overlap is necessary for =
best cylinder filling, but I wonder if 110=C2=B0 isn't too much?? The =
recommended valve lash is 0.40mm/0.016" when the rocker ratio is =
1.45(0.43mm/ with my 1.55 roller rockers). Would it be risky to set the =
valve lash at some 0.05mm/0.002" higher?
PS : is it common practice to set the valve lash at a couple of mm to =
perform a compression test, because it seems that the valve lash has a =
lot of influence on the result when testing a race camshaft?
Marcel
_______________________________________________
http://www.fot-racing.com <http://www.fot-racing.com/>
<http://www.team.net/donate.html>
Archive: http://autox.team.net/archive <http://autox.team.net/archive> =
http://www.team.net/pipermail/fot <http://www.team.net/pipermail/fot>
http://autox.team.net/mailman/options/fot/van.mulders.marcel@telenet.be =
<http://autox.team.net/mailman/options/fot/van.mulders.marcel@telenet.be>
_______________________________________________
http://www.fot-racing.com <http://www.fot-racing.com/>
<http://www.team.net/donate.html>
Archive: http://autox.team.net/archive <http://autox.team.net/archive> =
http://www.team.net/pipermail/fot <http://www.team.net/pipermail/fot>
http://autox.team.net/mailman/options/fot/sjanzen@me.com =
<http://autox.team.net/mailman/options/fot/sjanzen@me.com>
--Apple-Mail=_C1F52775-A676-4FF9-80D0-6A7E242FA4D8
Content-Transfer-Encoding: quoted-printable
charset=utf-8
<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html; =
charset=3Dutf-8"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; line-break: after-white-space;" =
class=3D"">Maercel, I=E2=80=99m puzzled. Are you referring to the lobe =
separation angle, or to the overlap between the intake valve opening =
before TDC and the exhaust valve closing after TDC on the same =
revolution? Unless I=E2=80=99m reading them wrong, I=E2=80=99ve =
looked at some pretty radical cam specs and the opening/closing overlap =
does not approach 110 degrees, more like 50 degrees on a really =
aggressive cam, but the lobe separation angle is about 104 degrees on =
the cam I have in the car and 107 on the cam I=E2=80=99m putting in =
another engine.<br class=3D""><div><br class=3D""><div class=3D"">On May =
2, 2020, at 4:30 PM, van.mulders.marcel--- via Fot <<a =
href=3D"mailto:fot@autox.team.net"; class=3D"">fot@autox.team.net</a>> =
wrote:</div><br class=3D"Apple-interchange-newline"><div class=3D""><div =
style=3D"caret-color: rgb(0, 0, 0); font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; font-family: Verdana, Arial, Helvetica, =
sans-serif; font-size: 10pt;" class=3D""><div class=3D""></div><div =
class=3D"">Hallo Chris,</div><div class=3D"">of course the cylinderhead =
has to be repaired. I think the man who has put the big valves in it, =
has taken too much risks : the valve seats (the rings that are pressed =
into the cyl head) are small where they do meet, and maybe the seats are =
distorted a bit because of this, but I don't know for sure, I will see =
when pulling the head. I know one cannot change the valve =
clearance too much, but maybe 0.05mm more valve lash is ok and it will =
reduce the valve overlap. I believe 110=C2=B0 overlap is a lot, even for =
a racecamshaft. Any idea's someone about that? The compression test with =
increased valve lash is much higher than with the recommended valve lash =
: I wonder if it is making any sense at all to check the compression of =
a race engine without increasing the valve lash : with the normal =
clearances, the inlet valve is closing when the piston has already =
travelled a lot upwards, hence the big difference between the =
compression test results with normal and with increased valve lash. So I =
think, if you want to test the compression, you have to increase the =
valve lash firstly(at least when the engine has a race =
camshaft).</div><div class=3D"">Marcel</div><div class=3D""><br =
class=3D""></div><hr id=3D"zwchr" data-marker=3D"__DIVIDER__" =
class=3D""><div data-marker=3D"__HEADERS__" class=3D""><b =
class=3D"">Van:<span =
class=3D"Apple-converted-space"> </span></b>"fot" <<a =
href=3D"mailto:fot@autox.team.net"; =
class=3D"">fot@autox.team.net</a>><br class=3D""><b =
class=3D"">Aan:<span =
class=3D"Apple-converted-space"> </span></b>"fot" <<a =
href=3D"mailto:fot@autox.team.net"; =
class=3D"">fot@autox.team.net</a>><br class=3D""><b =
class=3D"">Verzonden:<span =
class=3D"Apple-converted-space"> </span></b>Zaterdag 2 mei 2020 =
21:29:59<br class=3D""><b class=3D"">Onderwerp:<span =
class=3D"Apple-converted-space"> </span></b>Re: [Fot] Valve overlap =
and compression test<br class=3D""></div><div class=3D""><br =
class=3D""></div><div data-marker=3D"__QUOTED_TEXT__" class=3D""><div =
class=3D"WordSection1" style=3D"page: WordSection1;"><div style=3D"margin:=
0cm; font-size: 11pt; font-family: Calibri, sans-serif;" class=3D""><span=
lang=3D"DE" class=3D"">Hello Marcel,</span></div><p class=3D"MsoNormal" =
style=3D"margin: 0cm; font-size: 11pt; font-family: Calibri, =
sans-serif;"><span lang=3D"DE" class=3D""> </span></p><div =
style=3D"margin: 0cm; font-size: 11pt; font-family: Calibri, =
sans-serif;" class=3D"">Your engine has leaking valves.</div><div =
style=3D"margin: 0cm; font-size: 11pt; font-family: Calibri, =
sans-serif;" class=3D"">It won=E2=80=99t get better from changing =
measurement procedures.</div><div style=3D"margin: 0cm; font-size: 11pt; =
font-family: Calibri, sans-serif;" class=3D"">Maybe the seat is rough, =
or the valves bent, or offset .</div><div style=3D"margin: 0cm; =
font-size: 11pt; font-family: Calibri, sans-serif;" class=3D"">Something =
to make sure about.</div><p class=3D"MsoNormal" style=3D"margin: 0cm; =
font-size: 11pt; font-family: Calibri, sans-serif;"> </p><div =
style=3D"margin: 0cm; font-size: 11pt; font-family: Calibri, =
sans-serif;" class=3D"">Enlarging the valve leash could result in =
hammering everything dead in the valve train.</div><p class=3D"MsoNormal" =
style=3D"margin: 0cm; font-size: 11pt; font-family: Calibri, =
sans-serif;"> </p><div style=3D"margin: 0cm; font-size: 11pt; =
font-family: Calibri, sans-serif;" class=3D"">Cheers</div><div =
style=3D"margin: 0cm; font-size: 11pt; font-family: Calibri, =
sans-serif;" class=3D"">Chris</div><p class=3D"MsoNormal" style=3D"margin:=
0cm; font-size: 11pt; font-family: Calibri, sans-serif;"> </p><div =
class=3D""><div style=3D"border-style: solid none none; =
border-top-width: 1pt; border-top-color: rgb(225, 225, 225); padding: =
3pt 0cm 0cm;" class=3D""><div style=3D"margin: 0cm; font-size: 11pt; =
font-family: Calibri, sans-serif;" class=3D""><b class=3D""><span =
lang=3D"DE" class=3D"">Von:</span></b><span lang=3D"DE" class=3D""><span =
class=3D"Apple-converted-space"> </span>Fot <<a =
href=3D"mailto:fot-bounces@autox.team.net"; =
class=3D"">fot-bounces@autox.team.net</a>><span =
class=3D"Apple-converted-space"> </span><b class=3D"">Im Auftrag =
von<span =
class=3D"Apple-converted-space"> </span></b>van.mulders.marcel--- =
via Fot<br class=3D""><b class=3D"">Gesendet:</b><span =
class=3D"Apple-converted-space"> </span>Samstag, 2. Mai 2020 =
14:43<br class=3D""><b class=3D"">An:</b><span =
class=3D"Apple-converted-space"> </span>fot <<a =
href=3D"mailto:fot@autox.team.net"; =
class=3D"">fot@autox.team.net</a>><br class=3D""><b =
class=3D"">Betreff:</b><span =
class=3D"Apple-converted-space"> </span>[Fot] Valve overlap and =
compression test</span></div></div></div><p class=3D"MsoNormal" =
style=3D"margin: 0cm; font-size: 11pt; font-family: Calibri, =
sans-serif;"> </p><div class=3D""><div class=3D""><div =
style=3D"margin: 0cm; font-size: 11pt; font-family: Calibri, =
sans-serif;" class=3D""><span style=3D"font-size: 10pt; font-family: =
verdana, sans-serif;" class=3D"">A leaking test on my TR6 engine is =
showing a leaking exhaust valve on cyl no 1 (48% on the gauge of the =
device) and a leaking inlet valve on cyl no 2 (75%). Compression on cyl =
no1 is 9.5 bar and on cyl 2 it is 8 bar. The compression on the other =
cylinders is between 12 and 13.5 bar. This is with a race cam with a =
valve overlap of 110=C2=B0 (320-F grind). Because of the high overlap, =
the piston has risen a lot before the inlet valve is closed, so I did =
the compression test again, but with a valve lash of 2.5mm/0.1" : =
compression went from 9.5 bar to 14.5 on cyl no 1 and from 8 bar to 15 =
on cyl no 2. With this valve lash, the compression on the other =
cylinders went up to 16 - 18.5 bar. Of course, when the engine is =
running at high rpm, a lot of valve overlap is necessary for best =
cylinder filling, but I wonder if 110=C2=B0 isn't too much?? The =
recommended valve lash is 0.40mm/0.016" when the rocker ratio is =
1.45(0.43mm/ with my 1.55 roller rockers). Would it be risky to set the =
valve lash at some 0.05mm/0.002" higher?</span></div></div><div =
class=3D""><div style=3D"margin: 0cm; font-size: 11pt; font-family: =
Calibri, sans-serif;" class=3D""><span style=3D"font-size: 10pt; =
font-family: verdana, sans-serif;" class=3D"">PS : is it common practice =
to set the valve lash at a couple of mm to perform a compression test, =
because it seems that the valve lash has a lot of influence on the =
result when testing a race camshaft?</span></div></div><div =
class=3D""><div style=3D"margin: 0cm; font-size: 11pt; font-family: =
Calibri, sans-serif;" class=3D""><span style=3D"font-size: 10pt; =
font-family: verdana, sans-serif;" =
class=3D"">Marcel</span></div></div></div></div><br =
class=3D"">_______________________________________________<br =
class=3D""><a href=3D"mailto:fot@autox.team.net"; =
class=3D"">fot@autox.team.net</a><br class=3D""><br class=3D""><a =
href=3D"http://www.fot-racing.com/"; =
class=3D"">http://www.fot-racing.com</a><br class=3D""><br =
class=3D"">Donate:<span class=3D"Apple-converted-space"> </span><a =
href=3D"http://www.team.net/donate.html"; =
class=3D"">http://www.team.net/donate.html</a><br class=3D"">Archive:<span=
class=3D"Apple-converted-space"> </span><a =
href=3D"http://autox.team.net/archive"; =
class=3D"">http://autox.team.net/archive</a><span =
class=3D"Apple-converted-space"> </span><a =
href=3D"http://www.team.net/pipermail/fot"; =
class=3D"">http://www.team.net/pipermail/fot</a><br =
class=3D"">Unsubscribe/Manage:<span =
class=3D"Apple-converted-space"> </span><a =
href=3D"http://autox.team.net/mailman/options/fot/van.mulders.marcel@telen=
et.be" =
class=3D"">http://autox.team.net/mailman/options/fot/van.mulders.marcel@te=
lenet.be</a><br class=3D""></div></div><span style=3D"caret-color: =
rgb(0, 0, 0); font-family: Verdana-Bold; font-size: 13px; font-style: =
normal; font-variant-caps: normal; font-weight: normal; letter-spacing: =
normal; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D"">_______________________________________________</span><br =
style=3D"caret-color: rgb(0, 0, 0); font-family: Verdana-Bold; =
font-size: 13px; font-style: normal; font-variant-caps: normal; =
font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none;" class=3D""><a href=3D"mailto:fot@autox.team.net"; =
style=3D"font-family: Verdana-Bold; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
orphans: auto; text-align: start; text-indent: 0px; text-transform: =
none; white-space: normal; widows: auto; word-spacing: 0px; =
-webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" =
class=3D"">fot@autox.team.net</a><br style=3D"caret-color: rgb(0, 0, 0); =
font-family: Verdana-Bold; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><br style=3D"caret-color: rgb(0, 0, =
0); font-family: Verdana-Bold; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><a href=3D"http://www.fot-racing.com/"; =
style=3D"font-family: Verdana-Bold; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
orphans: auto; text-align: start; text-indent: 0px; text-transform: =
none; white-space: normal; widows: auto; word-spacing: 0px; =
-webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" =
class=3D"">http://www.fot-racing.com</a><br style=3D"caret-color: rgb(0, =
0, 0); font-family: Verdana-Bold; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><br style=3D"caret-color: rgb(0, 0, =
0); font-family: Verdana-Bold; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><span style=3D"caret-color: rgb(0, 0, =
0); font-family: Verdana-Bold; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D"">Donate:<span =
class=3D"Apple-converted-space"> </span></span><a =
href=3D"http://www.team.net/donate.html"; style=3D"font-family: =
Verdana-Bold; font-size: 13px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; orphans: auto; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; =
-webkit-text-stroke-width: 0px;" =
class=3D"">http://www.team.net/donate.html</a><br style=3D"caret-color: =
rgb(0, 0, 0); font-family: Verdana-Bold; font-size: 13px; font-style: =
normal; font-variant-caps: normal; font-weight: normal; letter-spacing: =
normal; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><span style=3D"caret-color: rgb(0, 0, =
0); font-family: Verdana-Bold; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D"">Archive:<span =
class=3D"Apple-converted-space"> </span></span><a =
href=3D"http://autox.team.net/archive"; style=3D"font-family: =
Verdana-Bold; font-size: 13px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; orphans: auto; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; =
-webkit-text-stroke-width: 0px;" =
class=3D"">http://autox.team.net/archive</a><span style=3D"caret-color: =
rgb(0, 0, 0); font-family: Verdana-Bold; font-size: 13px; font-style: =
normal; font-variant-caps: normal; font-weight: normal; letter-spacing: =
normal; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D""><span class=3D"Apple-converted-space"> </span></span><a =
href=3D"http://www.team.net/pipermail/fot"; style=3D"font-family: =
Verdana-Bold; font-size: 13px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; orphans: auto; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; =
-webkit-text-stroke-width: 0px;" =
class=3D"">http://www.team.net/pipermail/fot</a><br style=3D"caret-color: =
rgb(0, 0, 0); font-family: Verdana-Bold; font-size: 13px; font-style: =
normal; font-variant-caps: normal; font-weight: normal; letter-spacing: =
normal; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><span style=3D"caret-color: rgb(0, 0, =
0); font-family: Verdana-Bold; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D"">Unsubscribe/Manage:<span =
class=3D"Apple-converted-space"> </span></span><a =
href=3D"http://autox.team.net/mailman/options/fot/sjanzen@me.com"; =
style=3D"font-family: Verdana-Bold; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
orphans: auto; text-align: start; text-indent: 0px; text-transform: =
none; white-space: normal; widows: auto; word-spacing: 0px; =
-webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" =
class=3D"">http://autox.team.net/mailman/options/fot/sjanzen@me.com</a></d=
iv></div><br class=3D""></body></html>=
--Apple-Mail=_C1F52775-A676-4FF9-80D0-6A7E242FA4D8--
--===============5657152862949134756==
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Archive: http://autox.team.net/archive http://www.team.net/pipermail/fot
--===============5657152862949134756==--
|