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Marcel,
By any chance do you flush out your valve guides in the ports? The =
reason I ask is it raises hell with the valve grinder when they try to =
get a good square grind
for some reason.
jim g
=20
From: Fot <fot-bounces@autox.team.net> On Behalf Of =
van.mulders.marcel--- via Fot
Sent: Saturday, May 2, 2020 2:30 PM
To: tr4racing <tr4racing@googlemail.com>
Cc: fot <fot@autox.team.net>
Subject: Re: [Fot] Valve overlap and compression test
=20
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
=20
_____ =20
Verzonden: Zaterdag 2 mei 2020 21:29:59
Onderwerp: Re: [Fot] Valve overlap and compression test
=20
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
> Im Auftrag von 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
Archive: http://autox.team.net/archive http://www.team.net/pipermail/fot
http://autox.team.net/mailman/options/fot/van.mulders.marcel@telenet.be
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</o:shapelayout></xml><![endif]--></head><body lang=3DEN-US =
link=3D"#0563C1" vlink=3D"#954F72"><div class=3DWordSection1><p =
class=3DMsoNormal>Marcel,<o:p></o:p></p><p class=3DMsoNormal>By any =
chance do you flush out your valve guides in the ports? The reason I ask =
is it raises hell with the valve grinder when they try to get a good =
square grind<o:p></o:p></p><p class=3DMsoNormal>for some =
reason.<o:p></o:p></p><p class=3DMsoNormal>jim g<o:p></o:p></p><p =
class=3DMsoNormal><o:p> </o:p></p><div><div =
style=3D'border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in =
0in 0in'><p class=3DMsoNormal><b>From:</b> Fot =
<fot-bounces@autox.team.net> <b>On Behalf Of =
</b>van.mulders.marcel--- via Fot<br><b>Sent:</b> Saturday, May 2, 2020 =
2:30 PM<br><b>To:</b> tr4racing =
<tr4racing@googlemail.com><br><b>Cc:</b> fot =
<fot@autox.team.net><br><b>Subject:</b> Re: [Fot] Valve overlap =
and compression test<o:p></o:p></p></div></div><p =
class=3DMsoNormal><o:p> </o:p></p><div><div><p =
class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'>H=
allo Chris,<o:p></o:p></span></p></div><div><p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'>o=
f 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).<o:p></o:p></span></p></div><div><p =
class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'>M=
arcel<o:p></o:p></span></p></div><div><p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'><=
o:p> </o:p></span></p></div><div class=3DMsoNormal align=3Dcenter =
style=3D'text-align:center'><span =
style=3D'font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'><=
hr size=3D2 width=3D"100%" align=3Dcenter =
id=3Dzwchr></span></div><div><p class=3DMsoNormal><b><span =
style=3D'font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'>V=
an: </span></b><span =
style=3D'font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'>&=
quot;fot" <<a =
href=3D"mailto:fot@autox.team.net";>fot@autox.team.net</a>><br><b>Aan: =
</b>"fot" <<a =
href=3D"mailto:fot@autox.team.net";>fot@autox.team.net</a>><br><b>Verzo=
nden: </b>Zaterdag 2 mei 2020 21:29:59<br><b>Onderwerp: </b>Re: [Fot] =
Valve overlap and compression test<o:p></o:p></span></p></div><div><p =
class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'><=
o:p> </o:p></span></p></div><div><p class=3DMsoNormal><span =
lang=3DDE style=3D'color:black'>Hello Marcel,</span><span =
style=3D'color:black'><o:p></o:p></span></p><p class=3DMsoNormal><span =
lang=3DDE style=3D'color:black'> </span><span =
style=3D'color:black'><o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'color:black'>Your engine has leaking =
valves.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'color:black'>It won=E2=80=99t get better from changing =
measurement procedures.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'color:black'>Maybe the seat is rough, or the valves bent, or =
offset .<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'color:black'>Something to make sure =
about.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'color:black'> <o:p></o:p></span></p><p =
class=3DMsoNormal><span style=3D'color:black'>Enlarging the valve leash =
could result in hammering everything dead in the valve =
train.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'color:black'> <o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'color:black'>Cheers<o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'color:black'>Chris<o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'color:black'> <o:p></o:p></span></p><div><div =
style=3D'border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in =
0in 0in'><p class=3DMsoNormal><b><span lang=3DDE =
style=3D'color:black'>Von:</span></b><span lang=3DDE =
style=3D'color:black'> Fot <<a =
href=3D"mailto:fot-bounces@autox.team.net";>fot-bounces@autox.team.net</a>=
> <b>Im Auftrag von </b>van.mulders.marcel--- via =
Fot<br><b>Gesendet:</b> Samstag, 2. Mai 2020 14:43<br><b>An:</b> fot =
<<a =
href=3D"mailto:fot@autox.team.net";>fot@autox.team.net</a>><br><b>Betre=
ff:</b> [Fot] Valve overlap and compression test</span><span =
style=3D'color:black'><o:p></o:p></span></p></div></div><p =
class=3DMsoNormal><span =
style=3D'color:black'> <o:p></o:p></span></p><div><div><p =
class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'>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><span =
style=3D'color:black'><o:p></o:p></span></p></div><div><p =
class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'>P=
S : 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><span =
style=3D'color:black'><o:p></o:p></span></p></div><div><p =
class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'>M=
arcel</span><span =
style=3D'color:black'><o:p></o:p></span></p></div></div><p =
class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Verdana",sans-serif;color:black'><=
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";>http://www.fot-racing.com</a><br><br>D=
onate: <a =
href=3D"http://www.team.net/donate.html";>http://www.team.net/donate.html<=
/a><br>Archive: <a =
href=3D"http://autox.team.net/archive";>http://autox.team.net/archive</a> =
<a =
href=3D"http://www.team.net/pipermail/fot";>http://www.team.net/pipermail/=
fot</a><br>Unsubscribe/Manage: <a =
href=3D"http://autox.team.net/mailman/options/fot/van.mulders.marcel@tele=
net.be">http://autox.team.net/mailman/options/fot/van.mulders.marcel@tele=
net.be</a><o:p></o:p></span></p></div></div></div></body></html>
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fot@autox.team.net
http://www.fot-racing.com
Archive: http://autox.team.net/archive http://www.team.net/pipermail/fot
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