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Hi - They usually "jump" a tooth on overrun, or at least that's my experie=
nce. Or it can happen on a backfire... I had a Pontiac with a V8 back in th=
e day. The exhaust pipe broke before the muffler, so it had a really kool r=
umble sound. I used to take it out at night and drive exit ramps at "stupid=
speed" and then downshift the auto trans one gear to get the koolest sound=
... not to mention "power-off oversteer".=C2=A0 Drift City. After one of th=
ese excursions, the engine became very hard to start. I took the car off th=
e road and sold it to a friend. About a month later, he called me up all pi=
ssed off and wanting his $600 back because he had to fix the timing chain.
Never sold a car to a friend or associate ever again.
;-)
But in addition to the new chain and tensioner, take a close look at that c=
rank gear and make sure the "troughs" don't have a burr or the points aren'=
t sharp, either would indicate wear and you don't want that.
I don't recall a spec for play in the chain, but you want "as little as pos=
sible". If you can get the cam gear onto the cam easily with the chain thre=
aded, that's too loose.
C ya,Bob Lang
On Tuesday, November 26, 2019, 7:54:29 AM EST, Mathieu W. Huovinen <mad=
dhatt69@aol.com> wrote: =20
=20
=20
Bob and FOT,
I'm beginning to suspect a combination of a weak chain tensioner and an eng=
ine harmonic that may have caused it. Attached a pic of the play in the tim=
ing chain..about 1/2". Is that too much? If so, Ted, I'll be contacting you=
shortly. Chain is about two years old, maybe 6 weekend s of racing on it. =
New chain tensioner from Moss should be here today and I'm interested in se=
eing the difference in spring arch between the original single chain tensio=
ner and the new TR6 double chain tensioner. Stay tuned!
Mathieu=20
On Monday, November 25, 2019 Robert Lang <robertlangtr6@yahoo.com> wrote:
Hi - I've seen this before. Mostly on American V8's but the principle is t=
he same... It's almost always a loose chain or worn teeth on the crank gear=
. If the=C2=A0 crank gear has really sharp teeth, the gear is probably worn=
. Note that this is really easy to overlook. And I've had this problem with=
TR6 engines a couple of times. Especially if you sourced the inexpensive g=
ears. Seems like the hardening of the metal is wrong on some of the parts o=
ut there.
That said, the numbers look like you jumped more than one tooth. If the "ju=
mp" occurred on the crank end one tooth is about 17 degrees (360/21 teeth).=
Your mention of 150ish for your lobe center sound more like more than 34 d=
egrees or retard, the progression would be (roughly) 104 - good, 121 - not =
good, 138 - bad, 155 - really bad, etc. Note that I have seen engines run w=
ith more than 30 degrees of retard, but they ran very poorly!
I'd double check your crank gear for wear... actually, I'd just replace it =
along with the tensioner. Note that the current chain tensioners seem to be=
not as good as the OEM ones as the new ones wear fairly rapidly.
On the plus side, at least you didn't bend a valve in the process.
C ya,Bob Lang339-927-4489
On Sunday, November 24, 2019, 10:38:49 PM EST, Mathieu W. Huovinen via =
Fot <fot@autox.team.net> wrote: =20
=20
Fellas,
Sounds like we have the bearing cap strap issue resolved...who is up for an=
other mystery? Has anyone ever has their timing chain skip a tooth??
Final race on Saturday at the Turlkey Bowl this weekend at Summit Point. Tr=
iumph Spitfire..1296 engine. Double roller chain set. Car was running well =
all weekend, was out twice earlier that day. We leave false grid for the to=
set up for the first lap and I begin to accelerate. All of a sudden the ca=
r just dies and I coast off the track even before turn one. On the side of =
the track I couldn't start the car. In my mind I'm thinking my perrtonix di=
stributor just took a shit. Got towed in and all I'm thinking in pertronix.=
I swap in a points distributor and nothing. Perhaps my coil? Swap in a new=
coil. Nothing. Plugs perhaps? Swap in a good set of NGKs. Nothing. Not eve=
n a cough out of the engine. By this time I had run down the battery from t=
rying to start it so much. At this point I was jumping the racecar battery =
from my Tundra truck battery thinking perhaps a weak spark from a shot batt=
ery. Nothing. Was getting plenty of fuel because the plugs were wet. I even=
pulled and cleaned all the jets out of the Weber 45 DCOE just to make sure=
I was getting correct fuel. Fuel. Air. Spark. COMPRESSION. This next day (=
this morning) I did a compression test at the track. 80/70/70/70. What the =
heck? Thats not a blown head gasket..the cam HAS to be out of timing. I spe=
nt the majority of the 5 hour drive home trying to figure it out. Got home,=
car off trailer, straight to work. Pulled radiator, pulley, timing chain c=
over. No damage. Find TDC and put on my degree wheel. Pulled rockers and se=
t dial indicator on #1 intake. Tuned engine over to where cam sheet says wh=
ere #1 centerline is- 104 degrees after TDC while watching dial indicator. =
Went past 104 and dial was still climbing. Made it to to about 150ish degre=
es past TDC til indicator started to drop back down so I know I had went ri=
ght past the peak of the lobe. Pulled chain off carefully and rotated camsh=
aft until I found peak of lobe and moved crank back to 104 and set the chai=
n back on...about one tooth =C2=A0Put rockers back on and checked compressi=
on on #1. 160 PSI. That's as far as I got before my wife came down to yell =
art me. It was already 2130 at this point. More tomorrow as I put it back t=
ogether.=C2=A0
Thoughts? Ideas? Can the timing chain "float" at high revs? Thank-you in ad=
vance for any input!
V/r,
Mathieu Huovinen_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Archive: http://autox.team.net/archive http://www.team.net/pipermail/fot
@yahoo.com
=20
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<html><head></head><body><div class=3D"ydp611829c6yahoo-style-wrap" style=
=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 1=
3px;"><div></div>
<div dir=3D"ltr" data-setdir=3D"false">Hi - They usually "jump" a t=
ooth on overrun, or at least that's my experience. Or it can happen on a ba=
ckfire... I had a Pontiac with a V8 back in the day. The exhaust pipe broke=
before the muffler, so it had a really kool rumble sound. I used to take i=
t out at night and drive exit ramps at "stupid speed" and then downshift th=
e auto trans one gear to get the koolest sound... not to mention "power-off=
oversteer". Drift City. After one of these excursions, the engine be=
came very hard to start. I took the car off the road and sold it to a frien=
d. About a month later, he called me up all pissed off and wanting his $600=
back because he had to fix the timing chain.</div><div dir=3D"ltr" data-se=
tdir=3D"false"><br></div><div dir=3D"ltr" data-setdir=3D"false">Never sold =
a car to a friend or associate ever again.</div><div dir=3D"ltr" data-setdi=
r=3D"false"><br></div><div dir=3D"ltr" data-setdir=3D"false">;-)</div><div =
dir=3D"ltr" data-setdir=3D"false"><br></div><div dir=3D"ltr" data-setdir=3D=
"false">But in addition to the new chain and tensioner, take a close look a=
t that crank gear and make sure the "troughs" don't have a burr or the poin=
ts aren't sharp, either would indicate wear and you don't want that.</div><=
div dir=3D"ltr" data-setdir=3D"false"><br></div><div dir=3D"ltr" data-setdi=
r=3D"false">I don't recall a spec for play in the chain, but you want "as l=
ittle as possible". If you can get the cam gear onto the cam easily with th=
e chain threaded, that's too loose.<br></div><div dir=3D"ltr" data-setdir=
=3D"false"><br></div><div dir=3D"ltr" data-setdir=3D"false">C ya,</div><div=
dir=3D"ltr" data-setdir=3D"false">Bob Lang<br></div><div><br></div>
=20
</div><div id=3D"ydpae93fd03yahoo_quoted_5731993783" class=3D"ydpae=
93fd03yahoo_quoted">
<div style=3D"font-family:'Helvetica Neue', Helvetica, Arial, s=
ans-serif;font-size:13px;color:#26282a;">
=20
<div>
On Tuesday, November 26, 2019, 7:54:29 AM EST, Mathieu =
W. Huovinen <maddhatt69@aol.com> wrote:
</div>
<div><br></div>
<div><br></div>
<div><div id=3D"ydpae93fd03yiv5344134333"><div><p dir=3D"lt=
r">Bob and FOT,</p>
<p dir=3D"ltr">I'm beginning to suspect a combination of a weak chain tensi=
oner and an engine harmonic that may have caused it. Attached a pic of the =
play in the timing chain..about 1/2". Is that too much? If so, Ted, I'll be=
contacting you shortly. Chain is about two years old, maybe 6 weekend s of=
racing on it. New chain tensioner from Moss should be here today and I'm i=
nterested in seeing the difference in spring arch between the original sing=
le chain tensioner and the new TR6 double chain tensioner. Stay tuned!</p>
<p dir=3D"ltr">Mathieu </p>
<div class=3D"ydpae93fd03yiv5344134333device_aol_et_org_dt_dd_quote"></div>=
<hr style=3D"border-color: currentcolor; border-style: none; border-width: =
0px; min-height: 1px; color: rgb(153, 153, 153); background-color: rgb(153,=
153, 153); width: 100%; margin: 0px 0px 9px; padding: 0px;"><span style=3D=
"font-size:14px;color:#999999;">On Monday, November 25, 2019 Robert Lang &l=
t;<span style=3D"color:#0000A0;">robertlangtr6@yahoo.com</span>> wrote:<=
/span><br clear=3D"none"><div id=3D"ydpae93fd03yiv5344134333"></div></div><=
div class=3D"ydpae93fd03yiv5344134333yqt7004682114" id=3D"ydpae93fd03yiv534=
4134333yqt58219"><div><div><div class=3D"ydpae93fd03yiv5344134333ydpc7a6ebd=
8yahoo-style-wrap" style=3D"font-family:Helvetica Neue, Helvetica, Arial, s=
ans-serif;font-size:13px;"><div></div>
<div dir=3D"ltr">Hi - I've seen this before. Mostly on American V8'=
s but the principle is the same... It's almost always a loose chain or worn=
teeth on the crank gear. If the crank gear has really sharp teeth, t=
he gear is probably worn. Note that this is really easy to overlook. And I'=
ve had this problem with TR6 engines a couple of times. Especially if you s=
ourced the inexpensive gears. Seems like the hardening of the metal is wron=
g on some of the parts out there.<br clear=3D"none"></div><div dir=3D"ltr">=
<br clear=3D"none"></div><div dir=3D"ltr">That said, the numbers look like =
you jumped more than one tooth. If the "jump" occurred on the crank end one=
tooth is about 17 degrees (360/21 teeth). Your mention of 150ish for your =
lobe center sound more like more than 34 degrees or retard, the progression=
would be (roughly) 104 - good, 121 - not good, 138 - bad, 155 - really bad=
, etc. Note that I have seen engines run with more than 30 degrees of retar=
d, but they ran very poorly!</div><div dir=3D"ltr"><br clear=3D"none"></div=
><div dir=3D"ltr">I'd double check your crank gear for wear... actually, I'=
d just replace it along with the tensioner. Note that the current chain ten=
sioners seem to be not as good as the OEM ones as the new ones wear fairly =
rapidly.</div><div dir=3D"ltr"><br clear=3D"none"></div><div dir=3D"ltr">On=
the plus side, at least you didn't bend a valve in the process.</div><div =
dir=3D"ltr"><br clear=3D"none"></div><div dir=3D"ltr">C ya,</div><div dir=
=3D"ltr">Bob Lang</div><div dir=3D"ltr">339-927-4489<br clear=3D"none"></di=
v><div><br clear=3D"none"></div>
=20
</div><div class=3D"ydpae93fd03yiv5344134333ydpc2efc1c9yahoo_quoted=
" id=3D"ydpae93fd03yiv5344134333ydpc2efc1c9yahoo_quoted_5402201527">
<div style=3D"font-family:'Helvetica Neue', Helvetica, Arial, s=
ans-serif;font-size:13px;color:#26282a;">
=20
<div class=3D"ydpae93fd03yiv5344134333yqt1765380690" id=3D"=
ydpae93fd03yiv5344134333yqt19484"><div>
On Sunday, November 24, 2019, 10:38:49 PM EST, Mathieu =
W. Huovinen via Fot <fot@autox.team.net> wrote:
</div>
<div><br clear=3D"none"></div>
<div><br clear=3D"none"></div>
<div><div id=3D"ydpae93fd03yiv5344134333ydpc2efc1c9yiv06455=
07289">
<div style=3D"color:black;font-style:normal;font-weight:normal;font-stretch=
:normal;font-size:10pt;line-height:normal;font-family:arial;font-size-adjus=
t:none;">Fellas,
<div><br clear=3D"none">
</div>
<div>Sounds like we have the bearing cap strap issue resolved...who is up f=
or another mystery? Has anyone ever has their timing chain skip a tooth??</=
div>
<div><br clear=3D"none">
</div>
<div>Final race on Saturday at the Turlkey Bowl this weekend at Summit Poin=
t. Triumph Spitfire..1296 engine. Double roller chain set. Car was running =
well all weekend, was out twice earlier that day. We leave false grid for t=
he to set up for the first lap and I begin to accelerate. All of a sudden t=
he car just dies and I coast off the track even before turn one. On the sid=
e of the track I couldn't start the car. In my mind I'm thinking my perrton=
ix distributor just took a shit. Got towed in and all I'm thinking in pertr=
onix. I swap in a points distributor and nothing. Perhaps my coil? Swap in =
a new coil. Nothing. Plugs perhaps? Swap in a good set of NGKs. Nothing. No=
t even a cough out of the engine. By this time I had run down the battery f=
rom trying to start it so much. At this point I was jumping the racecar bat=
tery from my Tundra truck battery thinking perhaps a weak spark from a shot=
battery. Nothing. Was getting plenty of fuel because the plugs were wet. I=
even pulled and cleaned all the jets out of the Weber 45 DCOE just to make=
sure I was getting correct fuel. Fuel. Air. Spark. COMPRESSION. This next =
day (this morning) I did a compression test at the track. 80/70/70/70. What=
the heck? Thats not a blown head gasket..the cam HAS to be out of timing. =
I spent the majority of the 5 hour drive home trying to figure it out. Got =
home, car off trailer, straight to work. Pulled radiator, pulley, timing ch=
ain cover. No damage. Find TDC and put on my degree wheel. Pulled rockers a=
nd set dial indicator on #1 intake. Tuned engine over to where cam sheet sa=
ys where #1 centerline is- 104 degrees after TDC while watching dial indica=
tor. Went past 104 and dial was still climbing. Made it to to about 150ish =
degrees past TDC til indicator started to drop back down so I know I had we=
nt right past the peak of the lobe. Pulled chain off carefully and rotated =
camshaft until I found peak of lobe and moved crank back to 104 and set the=
chain back on...about one tooth Put rockers back on and checked comp=
ression on #1. 160 PSI. That's as far as I got before my wife came down to =
yell art me. It was already 2130 at this point. More tomorrow as I put it b=
ack together. </div>
<div><br clear=3D"none">
</div>
<div>Thoughts? Ideas? Can the timing chain "float" at high revs? Thank-you =
in advance for any input!</div>
<div><br clear=3D"none">
</div>
<div>V/r,</div>
<div><br clear=3D"none">
</div>
<div>Mathieu Huovinen</div>
</div></div>_______________________________________________<br clear=3D"non=
e"><a shape=3D"rect" href=3D"mailto:fot@autox.team.net"; rel=3D"nofollow" ta=
rget=3D"_blank">fot@autox.team.net</a><br clear=3D"none"><br clear=3D"none"=
><a shape=3D"rect" href=3D"http://www.fot-racing.com"; rel=3D"nofollow" targ=
et=3D"_blank">http://www.fot-racing.com</a><br clear=3D"none"><br clear=3D"=
none">Donate: <a shape=3D"rect" href=3D"http://www.team.net/donate.html"; re=
l=3D"nofollow" target=3D"_blank">http://www.team.net/donate.html</a><br cle=
ar=3D"none">Archive: <a shape=3D"rect" href=3D"http://autox.team.net/archiv=
e " rel=3D"nofollow" target=3D"_blank">http://autox.team.net/archive </a><a=
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target=3D"_blank">http://www.team.net/pipermail/fot</a><br clear=3D"none">=
/options/fot/robertlangtr6@yahoo.com" rel=3D"nofollow" target=3D"_blank">ht=
tp://autox.team.net/mailman/options/fot/robertlangtr6@yahoo.com</a><br clea=
r=3D"none"><br clear=3D"none"><br clear=3D"none"></div></div>
</div>
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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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