Help with late 60s 440 engine?
#1
Help with late 60s 440 engine?
I have a late 60s 440 engine i just completley rebuilt. And we put brand new spark plugs in it, and still cylinders #1 and #7 arent firing as the others are. Its perfectly timed and everything, they are just misfiring. Anyone know why? Can it be the valve seals?
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Jaredpishion (06-26-2012)
#3
"The basics"
Compression
Spark at the right time
Fuel
It's likely not fuel, unless there's a manifold leak at the 5 and 7 intake ports
So check compression, with both plugs removed or do a leakdown check
Valves? Opening closing? adjustment?
Have you checked spark at the plug end of the plug wires?
(Such things as a defective cap, bad wires, or even bad plugs)
Compression
Spark at the right time
Fuel
It's likely not fuel, unless there's a manifold leak at the 5 and 7 intake ports
So check compression, with both plugs removed or do a leakdown check
Valves? Opening closing? adjustment?
Have you checked spark at the plug end of the plug wires?
(Such things as a defective cap, bad wires, or even bad plugs)
The following users liked this post:
Jaredpishion (06-26-2012)
The following users liked this post:
Jaredpishion (06-26-2012)
The following users liked this post:
Jaredpishion (06-26-2012)
#6
Alright so i did a compression test, and compression in the good cylinders are reading around 100 and in the bad 1st and 7th cylinder it is reading around 25. I also did valve leakdown test and none of the valves are leaking. Is this a sign of bad piston rings? what is the problem?
#7
Might be a head gasket, cracked head. Ring or piston problems, it should show lots of oil
I assume with your leakdown you listened for leakage in the intake and exhaust? Did you look in the rad cap for bubbles? Run down someone with a coolant chemical test for combustion leakage.
I assume with your leakdown you listened for leakage in the intake and exhaust? Did you look in the rad cap for bubbles? Run down someone with a coolant chemical test for combustion leakage.
#8
Mopar Lover
Squirt a little bit of oil in the spark plug hole, and re test. See if compression raises or not.
If yes: bad rings and possibly more.
If no: valve issue, head gasket, cracked head, block, ect as 440roadrunner said.
If yes: bad rings and possibly more.
If no: valve issue, head gasket, cracked head, block, ect as 440roadrunner said.
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