I have a problem with my 360. I posted this to the FE forum too, as there may be some advice from non-FE people.

I replaced the plugs and wires, plus the distributor cap and rotor (along with changing the oil), and now the driver side bank of cylinders seems to be working fine. The headers are too hot to touch after several minutes of running. Unfortunately, the passenger side, after the same run time, is not getting hot. In fact, I can touch the headers without getting burned. If I go around to the exhaust, the driver side exhaust is pushing out quite a bit of gas, while the passenger side is blowing much less volume. Occasionally there is a backfire (or several in an row) and the engine is running pretty rough (but not as badly as I would expect). It doesn't start easily (it used to start immediately).

I am totally lost. It sounds like ignition but I have gone over the distributor and wires and everything is tight like it should be. Wires seem to be in their proper places, both according to the book and the previous cap and wires (I just pulled the cap with the wires still on it). If it were timing, it should be affecting both sides of the engine equally. At this point, the *only* difference that I can think of is that the plugs that were in the engine had a smaller gap (<.044) and the plugs I put in were gapped to about .045. The emission sticker says between .044 and .046. Again, though, the plugs on either side of the engine are the same, so if they are working on one side of the engine, they sure should be working on the other.

Help...

Mark

 

There is always a "cause and effect" history to the problem. So, did this just happen after you tuned it up, and all you did is what was listed above? Or are you resurrecting and motor that has had serious problems and you just got it running a little better than it was before by doing the tune-up. If this motor has had problems for awhile, I would begin by doing a compression check. But if it went from good to bad during the tune-up, things that come to mind are a serious vacuum leak or carb problem.

 

Good point about cause and effect. One other thing
that comes to mind. If this is a junkyard engine,
or you're just getting it up and running, do the
heads match?

Trail Rider

 

Sorry for the lack of info.

1974 F-100 28,000 original miles.

I recently bought the truck, and it has run rich since I got it.
I replaced exhaust manifolds with headers to get rid of an exhaust leak, and a sticking exhaust heat valfe (driver side). After doing that I noticed that all the header tubes except for cylinders 3 and 7 were getting hot enough to burn the paint off the headers. 3 and 7 still looked like they did when installed. Since cylinders 3 and 7 are right next to each other in the firing order, I assumed that the problem was ignition (with some help from the FE forum). So I decided that since I was changing the oil and filter I would do plugs, wires, cap and rotor.

Thanks for your help!

Mark

 

Ok, since you just bought the truck, and those two cylinders seem to have been "dead" since you got it, I would recommend a compression check to see what mechanical condition the engine is in.

 

I just rebuilt my 74 390. The old heads had cracked exhaust valves in #3&7. A compression test would answer that question. Something I found with the new engine installed and running extreamly rough was that the original distributor was shot. The engine would backfire every time I backed out of the gas. If you have a dwell meter you can tell if the distributor is working properly by watching the dwell. Set it with the vacuum advance disconnected and plugged off (a golf tee or old sparkplug works) 24-30 is where you want it. When you hook up the vacuum advance the dwell should stay the same. My old one would go from 29 to 4. Maybe this will help. Good luck!

 

It looks like I'll be checking the distributor and the compression, though I really think it is more an electrical problem than mechanical. In the beginning cyls 3&7 were cold, now cyls 1-4 are cold and 5-8 normal. Very wierd. I don't understand how it could be isolated to just one side of the engine.

Mark