--===============0783914521824334126==
boundary="=_8573c813-d1e2-40e2-b95f-1ad49006c102"
--=_8573c813-d1e2-40e2-b95f-1ad49006c102
Content-Transfer-Encoding: quoted-printable
Hallo Chris,=20
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 mayb=
e 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 clear=
ance too much, but maybe 0.05mm more valve lash is ok and it will reduce th=
e valve overlap. I believe 110=C2=B0 overlap is a lot, even for a racecamsh=
aft. Any idea's someone about that? The compression test with increased val=
ve lash is much higher than with the recommended valve lash : I wonder if i=
t is making any sense at all to check the compression of a race engine with=
out 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 in=
creased valve lash. So I think, if you want to test the compression, you ha=
ve to increase the valve lash firstly(at least when the engine has a race c=
amshaft).=20
Marcel=20
Van: "fot" <fot@autox.team.net>=20
Aan: "fot" <fot@autox.team.net>=20
Verzonden: Zaterdag 2 mei 2020 21:29:59=20
Onderwerp: Re: [Fot] Valve overlap and compression test=20
Hello Marcel,=20
Your engine has leaking valves.=20
It won=E2=80=99t get better from changing measurement procedures.=20
Maybe the seat is rough, or the valves bent, or offset .=20
Something to make sure about.=20
Enlarging the valve leash could result in hammering everything dead in the =
valve train.=20
Cheers=20
Chris=20
Von: Fot <fot-bounces@autox.team.net> Im Auftrag von van.mulders.marcel--- =
via Fot=20
Gesendet: Samstag, 2. Mai 2020 14:43=20
An: fot <fot@autox.team.net>=20
Betreff: [Fot] Valve overlap and compression test=20
A leaking test on my TR6 engine is showing a leaking exhaust valve on cyl n=
o 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 comp=
ression on the other cylinders is between 12 and 13.5 bar. This is with a r=
ace cam with a valve overlap of 110=C2=B0 (320-F grind). Because of the hig=
h 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" : com=
pression 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 11=
0=C2=B0 isn't too much?? The recommended valve lash is 0.40mm/0.016" when t=
he rocker ratio is 1.45(0.43mm/ with my 1.55 roller rockers). Would it be r=
isky to set the valve lash at some 0.05mm/0.002" higher?=20
PS : is it common practice to set the valve lash at a couple of mm to perfo=
rm a compression test, because it seems that the valve lash has a lot of in=
fluence on the result when testing a race camshaft?=20
Marcel=20
_______________________________________________=20
fot@autox.team.net=20
http://www.fot-racing.com=20
Archive: http://autox.team.net/archive http://www.team.net/pipermail/fot=20
arcel@telenet.be=20
--=_8573c813-d1e2-40e2-b95f-1ad49006c102
Content-Transfer-Encoding: quoted-printable
<html><body><div style=3D"font-family: Verdana, Arial, Helvetica, sans-seri=
f; font-size: 10pt; color: #000000"><div><style>/*<![CDATA[*/p.MsoNormal, l=
i.MsoNormal, div.MsoNormal {
=09margin: 0.0cm;
=09font-size: 11.0pt;
=09font-family: Calibri , sans-serif;
}
span.E-MailFormatvorlage18 {
=09font-family: Calibri , sans-serif;
=09color: windowtext;
}
*.MsoChpDefault {
=09font-size: 10.0pt;
}
div.WordSection1 {
=09page: WordSection1;
}
/*]]>*/</style></div><div>Hallo Chris,</div><div>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 t=
he head. I know one cannot change the valve clearance too much, but m=
aybe 0.05mm more valve lash is ok and it will reduce the valve overlap. I b=
elieve 110=C2=B0 overlap is a lot, even for a racecamshaft. Any idea's some=
one about that? The compression test with increased valve lash is much high=
er than with the recommended valve lash : I wonder if it is making any sens=
e at all to check the compression of a race engine without increasing the v=
alve lash : with the normal clearances, the inlet valve is closing wh=
en 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>Marcel</div><div><br></div><hr id=3D"zwchr" data-marker=3D"__DIVIDER_=
_"><div data-marker=3D"__HEADERS__"><b>Van: </b>"fot" <fot@autox.team.ne=
t><br><b>Aan: </b>"fot" <fot@autox.team.net><br><b>Verzonden: </b>=
Zaterdag 2 mei 2020 21:29:59<br><b>Onderwerp: </b>Re: [Fot] Valve overlap a=
nd compression test<br></div><div><br></div><div data-marker=3D"__QUOTED_TE=
XT__"><div class=3D"WordSection1"><p class=3D"MsoNormal"><span lang=3D"DE">=
Hello Marcel,</span></p><p class=3D"MsoNormal"><span lang=3D"DE"> </sp=
an></p><p class=3D"MsoNormal">Your engine has leaking valves.</p><p class=
=3D"MsoNormal">It won=E2=80=99t get better from changing measurement proced=
ures.</p><p class=3D"MsoNormal">Maybe the seat is rough, or the valves bent=
, or offset .</p><p class=3D"MsoNormal">Something to make sure about.</p><p=
class=3D"MsoNormal"> </p><p class=3D"MsoNormal">Enlarging the valve l=
eash could result in hammering everything dead in the valve train.</p><p cl=
ass=3D"MsoNormal"> </p><p class=3D"MsoNormal">Cheers</p><p class=3D"Ms=
oNormal">Chris</p><p class=3D"MsoNormal"> </p><div><div style=3D"borde=
r:none;border-top:solid #e1e1e1 1pt;padding:3pt 0cm 0cm 0cm"><p class=3D"Ms=
oNormal"><b><span lang=3D"DE">Von:</span></b><span lang=3D"DE"> Fot <fot=
-bounces@autox.team.net> <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 <f=
ot@autox.team.net><br><b>Betreff:</b> [Fot] Valve overlap and compressio=
n test</span></p></div></div><p class=3D"MsoNormal"> </p><div><div><p =
class=3D"MsoNormal"><span style=3D"font-size:10pt;font-family:'verdana' , s=
ans-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 i=
nlet 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 gri=
nd). Because of the high overlap, the piston has risen a lot before the inl=
et valve is closed, so I did the compression test again, but with a valve l=
ash of 2.5mm/0.1" : compression went from 9.5 bar to 14.5 on cyl no 1 and f=
rom 8 bar to 15 on cyl no 2. With this valve lash, the compression on the o=
ther cylinders went up to 16 - 18.5 bar. Of course, when the engine is runn=
ing at high rpm, a lot of valve overlap is necessary for best cylinder fill=
ing, 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" hig=
her?</span></p></div><div><p class=3D"MsoNormal"><span style=3D"font-size:1=
0pt;font-family:'verdana' , sans-serif;color:black">PS : is it common pract=
ice 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 w=
hen testing a race camshaft?</span></p></div><div><p class=3D"MsoNormal"><s=
pan style=3D"font-size:10pt;font-family:'verdana' , sans-serif;color:black"=
>Marcel</span></p></div></div></div><br>___________________________________=
____________<br>fot@autox.team.net<br><br>http://www.fot-racing.com<br><br>=
rchive http://www.team.net/pipermail/fot<br>Unsubscribe/Manage: http://auto=
x.team.net/mailman/options/fot/van.mulders.marcel@telenet.be<br></div></div=
></body></html>
--=_8573c813-d1e2-40e2-b95f-1ad49006c102--
--===============0783914521824334126==
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
--===============0783914521824334126==--
|