oh man, that would be devastating. Ok i will check my spark today. would that mean total rebuild of the engine if that happened? I don't see and metal in the oil

 

Yat, Let’s hope that is not the problem but you have to check everything just to be sure.

 

ok, so i just witnessed the light cutting out on the number 1 cylinder when revving the the engine. I did not see or notice that with any other cylinders. when idling it did not cut out at all.

could this be the issue?

 

Yat, It could be a cracked porcelain on the spark plug or even just a fouled plug, I have even found a small piece of carbon stuck between the electrode. Swap the #1 with another plug or get a new one.
Keep looking, you will eventually find the problem.

 

Being systematic is the key. Test one thing at a time. You have some intermittent behaviour on the #1 plug, so start there. First make sure you can describe what is happening and that it is repeating. In many cases we see something and jump to the next step before we have really observed the behaviour.

Next, pull that plug and examine it closely, pull a plug that is firing (#2 is convenient but #5 is a better analog because it is the same distance from the carb) and compare. Then if you still haven't found anything, reverse the plugs, re-install, and do the test again focussing on those two.

Make decisions based on verifiable information.

 

Oldtimers used to replace a spark plug if they dropped it, even an internal, invisible crack in the porcelain can cause a misfire. Swapping the plugs or wires around to see if the fault follows is a good idea.

 

ok i pulled the plugs and they are dry and very black. i am pretty sure its from the carb running rich and not being tuned.

also my dist does not have vacuum advance. Is this an issue also ?

 

True performance applications don't include vacuum advance, because they spend their time at the track, at full throttle. It is eliminated as a possible failure point, since it isn't doing anything anyway. If driving on the street, vacuum advance is recommended for cooler engine running. Also lose 3-4 hwy mpg without it.

 

Can you provide some history on your engine? How long have you had it, what has been done and when? Looking to understand how long it has run without changes before this developed. In particular curious how long the carb has been running the way it is (when was it last calibrated)?

Have you swapped the #1 plug with another location? BTW, if that doesn't help, change the plug wires next. Incidentally, one of the reasons for asking the history is to understand things like when the plugs were last changed and how old the wires are. When did you replace the cap and rotor, and was any of this coincidental to that?

 

Which carburetor do you have on the engine? As Ted mentioned about non vacuum advance distributors, they are best on race engines and marine applications.

 

yellow,

the engine was just built. No miles on the engine yet. Just break in and idling.

New rebuild engine and heads.
302 block 351 heads (iron)
new forged pistons
new cam COMP Cams K31-414-3 Magnum 224/224 Hydraulic Flat Cam K-Kit
original crank and rods (conditioned)
bored 20 over
new Holley 80457sa (still not completely tuned)
new plugs
new wires
new cap
used Malloy Unilite dist (was on the original motor when i purchased the truck)
used Weined intake


Started the engine and did the break in. Truck will idle but the carburetor is all out of adjustment. When i shift into gear it wants to die and seems to run supper rich. I pull the plugs and the plugs are black, dry and very sooty.

note: after reading the Mallory website the PO never had a ignition ballast resistor hooked up, so i did not either. this is from the Mallory website

NOTE: The purpose of an ignition ballast resistor between the ignition switch (12V) and the ignition coil positive terminal is to restrict current flow through the ignition coil. Failure to use an ignition ballast resistor will eventually destroy the Ignition Module.

I just got a new vacuum advanced dist with new wires and coil yesterday. i am goin to swap it out and hopefully fix any issues.

 

thanks Kenny

 

If you are running the original ignition wire(pink) from the key to the coil, it will be a resistor wire(built in) so no need for another ballast resistor.

NOTE: Do NOT IDLE that engine for long. It needs rpm to keep the oil up on the cam/lifters. You don't want to have to replace the cam(which many people have had to do) from excessive idling on a new motor.

I see from past comments you have an issue with #1 plug miss firing. Have you swapped plugs to see if it follows the plug? There has been more then one instance where even a new plug is bad. If the porcelain is cracked it will misfire under any kind of "Load" as the spark tries to find the easiest path to ground. I would remove those heat shields you have on the plug wires until you have this figured out. Even the wire could be sparking down by the head and you can't see it with those sleeves on there.

As for no vacuum advance. Yes, it would help, but not necessary. What is your initial timing set to now? When you rev it up, what does it go to? Those two numbers are where you start at for setting the timing curve. The advance plate inside the distributor has adjustments you can move, along with springs to adjust how fast the timing comes up. I'd say you need to be around 10* initial at idle for a good start point. With that set, you can then adjust the mixture screws on the carb to get it dialed in and try to lean it out.

BTW, beautiful engine. Nicely done.

 

Nice looking mill. I'm not an SBF guy, only engine I built was my 445 FE, but I believe all the trucks in this era came with a ballast resistor in the wire from the ignition to the coil. I had to bypass it for the MSD 6AL I'm running (BTW wouldn't do that again).

I don't run vacuum advance since I don't care about fuel economy (not that I'm rich, I just don't drive it that much and when I do it is mostly at WOT), but it should not be a factor. Replacing the distributor, coil, and wires is an expensive way to fix the problem, but it may work. I suggest throwing in some fresh plugs since you are going shotgun with your approach.

As mentioned I'm not an SBF guy, but where is your initial advance, and what is your total? 10 degrees initial seems pretty small. My FE is not representative, but it likes 26 degrees, and 34 total. Get your timing sorted before you mess with the carb. That carb from the factory should be pretty close for the engine you have, with the exception of initial blade position and idle mixture etc. BTW, I eliminated the choke until I had the engine happy. Just adds another factor you don't need for initial set up.

 

thank you. it did not follow the plug when i moved to #5. I did notice the the number one plug was lose that may have been the problem with the misfire. I am going to play with timing today and report back.

I am afraid i destroyed the cam from the idling. crap