460 knock problem
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Junior User
Joined: Jan 2004
Posts: 58
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From: Bothell WA
460 knock problem
i have an 81' f-250 with a 460,
no matter where you set the timing 8* to 20* it knocks
the exhaust blows blackish smoke.
and at 8*- 15* there is no power, at 20* plenty of power
carb has been rebuilt, and i checked for vacaum leaks and found none
any one know what to do besides buying an msd box ??
no matter where you set the timing 8* to 20* it knocks
the exhaust blows blackish smoke.
and at 8*- 15* there is no power, at 20* plenty of power
carb has been rebuilt, and i checked for vacaum leaks and found none
any one know what to do besides buying an msd box ??
Hotshot
Joined: Feb 2004
Posts: 11,697
Likes: 3
From: Marengo, Iowa
you may have to put the timing light down and ear tune it, as the balancer ring may have shifted. Carb is rich for some reason, whether dripping fuel or choke not opening, depends on the carb as to whether there is more to be checked. Check for proper advance as well, the mechanical or vacuum advances may be stuck or failed.
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Junior User
Joined: Jan 2004
Posts: 58
Likes: 0
From: Bothell WA
i have played with the carb settings alot, and found you go to far one way..the truck wants to die, which is a givin, a buddy of mine and i took a timing light and adjusted the settings according to max idle rpm, i don't think that was the best idea,
as far as timing goes, i've tried to ear time it, but no matter where i put it, it either dies at idle...or runs crapy or runs strong....but no matter where you put it.. it knocks under a load
i talked to the guys at schucks, and they suggested that i change the plugs and such, and finely sand down the contacts on the distributer cap and rotor, and see if that helps.
as far as timing goes, i've tried to ear time it, but no matter where i put it, it either dies at idle...or runs crapy or runs strong....but no matter where you put it.. it knocks under a load
i talked to the guys at schucks, and they suggested that i change the plugs and such, and finely sand down the contacts on the distributer cap and rotor, and see if that helps.
Tuned
Joined: May 2003
Posts: 345
Likes: 4
From: Southern IL
I am a 460 person myself and had one once that did the same thing. It turned out that the roll pin on the distributor gear was sheared off and catching, sometimes. Rebuilt dist. at Autozone for around 125 and good to go.
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Junior User
Joined: Jan 2004
Posts: 58
Likes: 0
From: Bothell WA
i just changed the oil..and it's full....and my second guess was the distributer..i had been looking into these HEI disb.'s and it seems like a good idea ish....i'm not to up on them..but i can soon learn....i also talked to a mechanic friend of mine,...and he said it may be a broken valve spring...or a warn lobe on the cam shaft...BECAUSE...it doesn't fire on number 3 at idle...you can pull off the wire and it does nothing......no change...now i don't have the guts to wrap it up to 2500 rpms and take it off....but i know it knocks....pings....and doesn't have BBF power like it should....it' shard to spin the back tires....the motor gets reall hot....plugs looked like crap..that kinda thing....so i'm not sure what to do...
