351c cylinder miss |
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ramair351
Senior Member Joined: 08-May-2006 Location: west michigan Status: Offline Points: 1561 |
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Posted: 15-August-2013 at 12:36PM |
I've been tinkering with the torino engine tonight. its a stock 72 351c with 69k miles. it just doesnt run smooth, definately has a miss. but it is responsive, and has no problem picking up rpms, timing is set at 8 degrees. plugs are good, wires are good, has a pertronix now. it had points and i thought that may be the problem so i swapped them-but runs the same.
the weird thing is, i cant seem to find a dead hole, i pull a plug wire, the rpms drop and i think that must be one, but next time i do it, that cyl is fine and another one sounds funny. this one has me kind of stumped, i am beginning to think it jumped time, because when i have the timing at 8 degrees, the rotor is pointing to #8 cyl on cap. any thoughts?
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-Pete
1972 montego GT 1970 Torino cobra SCJ 1970 mustang mach 1 1965 Falcon futura |
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75GranMan
Senior Member Joined: 05-April-2011 Location: Colchester, CT Status: Offline Points: 1225 |
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When you pull a wire and the rpm's drop..that means the cylinder is contributing, how much is the question.If you pull a wire and rpm doesn't change means that cylinder isn't contributing. Was the dist timing off and you set it back to 8 degrees? preform a compression ck to see what compression is at for all the cylinders.
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John 75Gran Torino 4spd
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ramair351
Senior Member Joined: 08-May-2006 Location: west michigan Status: Offline Points: 1561 |
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when i got the car, it ran a little rough, and i felt a miss. so i checked the timing. i noticed the balancer had spun, so bad the outer ring was nearly off the rubber. Well i cant time it that way so i put on a new balancer. then i went to check the timing, well guess what the distributor was frozen, a week later and i got that to move. then i could set the timing. at this point it still had a points ignition. and had a miss. swapped it all over to pertronix. still misses. thats where i am now. i know i need to do a compression check, but if it jumped time, that could not be correct too i am thinking.
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-Pete
1972 montego GT 1970 Torino cobra SCJ 1970 mustang mach 1 1965 Falcon futura |
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ramair351
Senior Member Joined: 08-May-2006 Location: west michigan Status: Offline Points: 1561 |
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i am thinking one side of the carb is leaning out, the pulgs on the cyls in question are very white. i swapped an old 302 carb on it, and while its not right, it seems better. keep you all posted
does a 72 351c have pastic timing gears? if it jumped time would it run at all?
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-Pete
1972 montego GT 1970 Torino cobra SCJ 1970 mustang mach 1 1965 Falcon futura |
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stanman
Senior Member Joined: 23-March-2007 Location: Nova Scotia, Ca Status: Offline Points: 1432 |
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Some engines will run (not well) if they jump their time. Not sure about a 351C. In case you don't already know there's an easy way to check the "health" of your timing chain.
Remove the distributor cap so you can see the rotor. Put a socket and long power bar (?) on crank bolt. Turn one way until rotor moves. Now turn the opposite way until it reverses direction. If you had to turn the crank a little, that's good. If you had to turn the crank a lot, that bad...very bad!!
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aquartlow
Senior Member Joined: 19-December-2011 Location: Summerfield, Fl Status: Offline Points: 2270 |
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Years ago (1985), I remember replacing a timing set on my sister's '73 Gran Torino w/ 351C 4bbl and it had jumped time, found the stock cam gear had nylon teeth.
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www.supermotors.net/22468
Yeah, It's a Hybrid...It burns gas and tires. No matter how good she looks, somebody, somewhere, is tired of her sh*t. Beauty is skin deep, ugliness goes clear to the bone. |
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Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6059 |
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i'd take a look at the lifter pre-load, if they're set deep it can play havoc, the engine just strugglesI've found that setting them very lightly around a 1/4 turn the engine runs better & is freer to rev
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72 GT Ute
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