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351c cylinder miss

Printed From: The Ford Torino Page
Category: Model Specific Forum
Forum Name: 1972-1976 Ford and Mercury
Forum Description: Technical discussion for 1972-1976 Ford and Mercury
URL: https://forum.grantorinosport.org/forum_posts.asp?TID=9623
Printed Date: 28-March-2024 at 11:29AM
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com


Topic: 351c cylinder miss
Posted By: ramair351
Subject: 351c cylinder miss
Date 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






Replies:
Posted By: 75GranMan
Date Posted: 15-August-2013 at 2:26PM
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
Tighten it down until it snaps and then back it off a half turn!


Posted By: ramair351
Date Posted: 15-August-2013 at 4:00PM
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





Posted By: ramair351
Date Posted: 16-August-2013 at 2:34PM
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





Posted By: stanman
Date Posted: 18-August-2013 at 2:30AM
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!!


Posted By: aquartlow
Date Posted: 18-August-2013 at 5:07AM
Originally posted by ramair351 ramair351 wrote:

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?
 
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.


Posted By: Rockatansky
Date Posted: 18-August-2013 at 6:09AM
i'd take a look at the lifter pre-load, if they're set deep it can play havoc, the engine just struggles
I'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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