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Hi Jim,=20
The valve guides have an oval shape in the ports, but are not shortened.=20
Marcel=20
Van: "Jim Gray" <toodamnfunky@comcast.net>=20
Aan: "van mulders marcel" <van.mulders.marcel@telenet.be>, "tr4racing" <tr4=
racing@googlemail.com>=20
Cc: "fot" <fot@autox.team.net>=20
Verzonden: Zaterdag 2 mei 2020 23:30:42=20
Onderwerp: RE: [Fot] Valve overlap and compression test=20
Marcel,=20
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 s=
quare grind=20
for some reason.=20
jim g=20
From: Fot <fot-bounces@autox.team.net> On Behalf Of van.mulders.marcel--- v=
ia Fot=20
Sent: Saturday, May 2, 2020 2:30 PM=20
To: tr4racing <tr4racing@googlemail.com>=20
Cc: fot <fot@autox.team.net>=20
Subject: Re: [Fot] Valve overlap and compression test=20
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" < [ mailto:fot@autox.team.net | fot@autox.team.net ] >=20
Aan: "fot" < [ mailto:fot@autox.team.net | 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 < [ mailto:fot-bounces@autox.team.net | fot-bounces@autox.team.net=
] > Im Auftrag von van.mulders.marcel--- via Fot=20
Gesendet: Samstag, 2. Mai 2020 14:43=20
An: fot < [ mailto:fot@autox.team.net | 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
[ mailto:fot@autox.team.net | fot@autox.team.net ]=20
[ http://www.fot-racing.com/ | http://www.fot-racing.com ]=20
]=20
Archive: [ http://autox.team.net/archive | http://autox.team.net/archive ] =
[ http://www.team.net/pipermail/fot | http://www.team.net/pipermail/fot ]=
=20
.marcel@telenet.be | http://autox.team.net/mailman/options/fot/van.mulders.=
marcel@telenet.be ]=20
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/*]]>*/</style></div><div>Hi Jim,</div><div>The valve guides have an oval s=
hape in the ports, but are not shortened. </div><div>Marcel</div><div>=
<br></div><hr id=3D"zwchr" data-marker=3D"__DIVIDER__"><div data-marker=3D"=
__HEADERS__"><b>Van: </b>"Jim Gray" <toodamnfunky@comcast.net><br><b>=
Aan: </b>"van mulders marcel" <van.mulders.marcel@telenet.be>, "tr4ra=
cing" <tr4racing@googlemail.com><br><b>Cc: </b>"fot" <fot@autox.te=
am.net><br><b>Verzonden: </b>Zaterdag 2 mei 2020 23:30:42<br><b>Onderwer=
p: </b>RE: [Fot] Valve overlap and compression test<br></div><div><br></div=
><div data-marker=3D"__QUOTED_TEXT__"><div class=3D"WordSection1"><p class=
=3D"MsoNormal">Marcel,</p><p class=3D"MsoNormal">By any chance do you flush=
out your valve guides in the ports? The reason I ask is it raises hell wit=
h the valve grinder when they try to get a good square grind</p><p class=3D=
"MsoNormal">for some reason.</p><p class=3D"MsoNormal">jim g</p><p class=3D=
"MsoNormal"> </p><div><div style=3D"border:none;border-top:solid #e1e1=
e1 1pt;padding:3pt 0in 0in 0in"><p class=3D"MsoNormal"><b>From:</b> Fot <=
;fot-bounces@autox.team.net> <b>On Behalf Of </b>van.mulders.marcel--- v=
ia Fot<br><b>Sent:</b> Saturday, May 2, 2020 2:30 PM<br><b>To:</b> tr4racin=
g <tr4racing@googlemail.com><br><b>Cc:</b> fot <fot@autox.team.net=
><br><b>Subject:</b> Re: [Fot] Valve overlap and compression test</p></d=
iv></div><p class=3D"MsoNormal"> </p><div><div><p class=3D"MsoNormal">=
<span style=3D"font-size:10pt;font-family:'verdana' , sans-serif;color:blac=
k">Hallo Chris,</span></p></div><div><p class=3D"MsoNormal"><span style=3D"=
font-size:10pt;font-family:'verdana' , sans-serif;color:black">of course th=
e cylinderhead has to be repaired. I think the man who has put the big valv=
es in it, has taken too much risks : the valve seats (the rings that are pr=
essed 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 t=
oo much, but maybe 0.05mm more valve lash is ok and it will reduce the valv=
e overlap. I believe 110=C2=B0 overlap is a lot, even for a racecamshaft. A=
ny idea's someone about that? The compression test with increased valve las=
h is much higher than with the recommended valve lash : I wonder if it is m=
aking any sense at all to check the compression of a race engine without in=
creasing the valve lash : with the normal clearances, the inlet valve is&nb=
sp; 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).</span></p></div><div><p class=3D"MsoNormal"><span style=3D"font-s=
ize:10pt;font-family:'verdana' , sans-serif;color:black">Marcel</span></p><=
/div><div><p class=3D"MsoNormal"><span style=3D"font-size:10pt;font-family:=
'verdana' , sans-serif;color:black"> </span></p></div><div class=3D"Ms=
oNormal" align=3D"center" style=3D"text-align:center"><span style=3D"font-s=
ize:10pt;font-family:'verdana' , sans-serif;color:black"><hr size=3D"2" wid=
th=3D"100%" align=3D"center" id=3D"zwchr"></span></div><div><p class=3D"Mso=
Normal"><b><span style=3D"font-size:10pt;font-family:'verdana' , sans-serif=
;color:black">Van: </span></b><span style=3D"font-size:10pt;font-family:'ve=
rdana' , sans-serif;color:black">"fot" <<a href=3D"mailto:fot@autox.team=
.net" target=3D"_blank" rel=3D"nofollow noopener noreferrer">fot@autox.team=
.net</a>><br><b>Aan: </b>"fot" <<a href=3D"mailto:fot@autox.team.net"=
target=3D"_blank" rel=3D"nofollow noopener noreferrer">fot@autox.team.net<=
/a>><br><b>Verzonden: </b>Zaterdag 2 mei 2020 21:29:59<br><b>Onderwerp: =
</b>Re: [Fot] Valve overlap and compression test</span></p></div><div><p cl=
ass=3D"MsoNormal"><span style=3D"font-size:10pt;font-family:'verdana' , san=
s-serif;color:black"> </span></p></div><div><p class=3D"MsoNormal"><sp=
an lang=3D"DE" style=3D"color:black">Hello Marcel,</span><span style=3D"col=
or:black"></span></p><p class=3D"MsoNormal"><span lang=3D"DE" style=3D"colo=
r:black"> </span><span style=3D"color:black"></span></p><p class=3D"Ms=
oNormal"><span style=3D"color:black">Your engine has leaking valves.</span>=
</p><p class=3D"MsoNormal"><span style=3D"color:black">It won=E2=80=99t get=
better from changing measurement procedures.</span></p><p class=3D"MsoNorm=
al"><span style=3D"color:black">Maybe the seat is rough, or the valves bent=
, or offset .</span></p><p class=3D"MsoNormal"><span style=3D"color:black">=
Something to make sure about.</span></p><p class=3D"MsoNormal"><span style=
=3D"color:black"> </span></p><p class=3D"MsoNormal"><span style=3D"col=
or:black">Enlarging the valve leash could result in hammering everything de=
ad in the valve train.</span></p><p class=3D"MsoNormal"><span style=3D"colo=
r:black"> </span></p><p class=3D"MsoNormal"><span style=3D"color:black=
">Cheers</span></p><p class=3D"MsoNormal"><span style=3D"color:black">Chris=
</span></p><p class=3D"MsoNormal"><span style=3D"color:black"> </span>=
</p><div><div style=3D"border:none;border-top:solid #e1e1e1 1pt;padding:3pt=
0in 0in 0in"><p class=3D"MsoNormal"><b><span lang=3D"DE" style=3D"color:bl=
ack">Von:</span></b><span lang=3D"DE" style=3D"color:black"> Fot <<a hre=
f=3D"mailto:fot-bounces@autox.team.net"; target=3D"_blank" rel=3D"nofollow n=
oopener noreferrer">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"; target=3D"_=
blank" rel=3D"nofollow noopener noreferrer">fot@autox.team.net</a>><br><=
b>Betreff:</b> [Fot] Valve overlap and compression test</span><span style=
=3D"color:black"></span></p></div></div><p class=3D"MsoNormal"><span style=
=3D"color:black"> </span></p><div><div><p class=3D"MsoNormal"><span st=
yle=3D"font-size:10pt;font-family:'verdana' , sans-serif;color:black">A lea=
king 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 compressi=
on on the other cylinders is between 12 and 13.5 bar. This is with a race c=
am with a valve overlap of 110=C2=B0 (320-F grind). Because of the high ove=
rlap, 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" : compress=
ion 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 va=
lve 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 r=
ocker 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"c=
olor:black"></span></p></div><div><p class=3D"MsoNormal"><span style=3D"fon=
t-size:10pt;font-family:'verdana' , sans-serif;color:black">PS : is it comm=
on practice to set the valve lash at a couple of mm to perform a compressio=
n 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"></sp=
an></p></div><div><p class=3D"MsoNormal"><span style=3D"font-size:10pt;font=
-family:'verdana' , sans-serif;color:black">Marcel</span><span style=3D"col=
or:black"></span></p></div></div><p class=3D"MsoNormal"><span style=3D"font=
-size:10pt;font-family:'verdana' , sans-serif;color:black"><br>____________=
___________________________________<br><a href=3D"mailto:fot@autox.team.net=
" target=3D"_blank" rel=3D"nofollow noopener noreferrer">fot@autox.team.net=
</a><br><br><a href=3D"http://www.fot-racing.com"; target=3D"_blank" rel=3D"=
nofollow noopener noreferrer">http://www.fot-racing.com</a><br><br>Donate: =
<a href=3D"http://www.team.net/donate.html"; target=3D"_blank" rel=3D"nofoll=
ow noopener noreferrer">http://www.team.net/donate.html</a><br>Archive: <a =
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opener noreferrer">http://autox.team.net/archive</a> <a href=3D"http://www.=
team.net/pipermail/fot" target=3D"_blank" rel=3D"nofollow noopener noreferr=
er">http://www.team.net/pipermail/fot</a><br>Unsubscribe/Manage: <a href=3D=
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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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