My truck was in the shop getting a new tire... while it was inthere it also got a new coil and points. I took it home and it drove fine but i decided to look at one of the spark plugs and they were burnt pretty bad, so i put in some autolites. It runs good but.. i dont wanna say rough but sorda rough at idle. what im asking is when u set the the point gap and timing do they have anything to do with the plugs... will u have to set the gap and stuff again.... the main reason i change them is because when i used to give it a lot of gas it had a very big OOOMMMPHHH if u know what i mean. now it seems to accelerate slower.... y could this be. thanks, i used to run it with the oil a little low sometimes could this amtter?

 

Hi Chris,

Yes, when you install plugs you should always confirm their gap first.

I trust you installed Autolite 45's proper gap would be .034"

What colour where your plugs when you took tham out ?
A Brown colour is normal.





Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg



Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's"


78 F-150 429CJ,Silver, Explorer Pkg.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon

 

yes i know there supposed to be set at .34 i did that, so there supposed to be a brownish color?

 

There are two different brown's.
One from Normal burning and another from Over-heating.

I'll see if I can find a chart for you.


Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg



Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's"


78 F-150 429CJ,Silver, Explorer Pkg.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon

 

Here is a web page with some pretty good pics showing spark plugs with different conditions.

http://www.centuryperformance.com/spark2.htm

The best way to read plugs is to install new plugs, drive around until the engine is thoroughly warmed up, then shut the engine off, coast to the side of the road, and pull a plug. If you just drive to a stop like you normally would you won't get the most accurate reading.

To answer your question about points and timing, any change in the ignition system changes everything else in the system as well. If the plug is borderline on being too hot, then you bump up the timing, odds are you will have problems with detonation. If the plug is borderline on being too cold and you retard the timing it won't be unusual to foul plugs because they won't get hot enough to burn off deposits.

You mention that the plugs looked burnt, this can be caused by many things. Did the shop adjust the carburetor when they tuned it up? If the carb is too lean that will cause higher cylinder temps and burnt plugs. Vacuum leaks are also a common suspect. When I built my 390 the first time I had a vacuum leak under the intake and it caused all kinds of problems until I found it and fixed it.

Anyway, take a look at the plugs on the link above and see which one looks most like what you have. That will give you an idea on what you need check.

Hope this helps.

Clark