valve timing?
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Joined: Mar 2001
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From: washington state
valve timing?
Here are the facts that bring me once again to this great group.
73 F250HD Camper Special.
460CI running points and coil.
Ignition Timing at about 10 degrees(provides best"keep running idle")
Slow to start...have to feed the gas and crank unless engine is warmed up.
Good power and acceleration over the full RPM range.
There are no air leaks around the intake manifold or carburator.
At idle NO VACUUM reading at the intake manifold.
At RPMs above idle vacuum gauge reads steady at around 10in/hg.
Idle jet screws set at 1.5 turns<>.
Idles like a 1/4mile dragster(lopes)
Compression within 5lbs. of 130lbs. for all cylingders
OK the no vacuum at idle and low vacuum at speed leads me to believe that...
1. The timing chain has jumped a tooth? So anyone out there have and easy way to prove valve timing without pulling the whole front end off the truck and engine?
OR
2. Sometime in the past an RV type cam has been installed?
3. It is something else that I am not or I forgot to check...(it usually is)
Thanks in advance for the input..
ROB
73 F250HD Camper Special.
460CI running points and coil.
Ignition Timing at about 10 degrees(provides best"keep running idle")
Slow to start...have to feed the gas and crank unless engine is warmed up.
Good power and acceleration over the full RPM range.
There are no air leaks around the intake manifold or carburator.
At idle NO VACUUM reading at the intake manifold.
At RPMs above idle vacuum gauge reads steady at around 10in/hg.
Idle jet screws set at 1.5 turns<>.
Idles like a 1/4mile dragster(lopes)
Compression within 5lbs. of 130lbs. for all cylingders
OK the no vacuum at idle and low vacuum at speed leads me to believe that...
1. The timing chain has jumped a tooth? So anyone out there have and easy way to prove valve timing without pulling the whole front end off the truck and engine?
OR
2. Sometime in the past an RV type cam has been installed?
3. It is something else that I am not or I forgot to check...(it usually is)
Thanks in advance for the input..
ROB
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