Smokin

[Rob Z]

I consider myself a dicent mechanic. I've kept my cars running, rebuilt engines, repaired what was needed and it has worked up untill now.

The problem chield is my 69 with a 302 2brl, stock with rebuilt heads a couple of years ago. It has been getting VERY poor gas milage so I started looking into possible issues. About a month ago pulled the plugs and they were BLACK with soot. Way to rich. Since then I have rebuilt the 2brl, replaced the plugs, wires, cap, rotor and coil. The dist has a pertronix kit which I verified the gap and timming (10deg BTDC). Well it still puffs black smoke out the pipes and idle is a little rough, it will stumble fom time to time. Best I can tell all is right, but the smoke says different.

So where do I go, what should I tripple check. I know I'm missing something.

Thanks

 

[garner67]

Have you rechecked the spark plugs after you rebuilt the carb and replaced the plugs, wires, cap, etc?

Sounds like it could still be running rich.

 

[johnpro]

Have you rechecked the spark plugs after you rebuilt the carb and replaced the plugs, wires, cap, etc?

Sounds like it could still be running rich.

:wstup

After you rebuilt the carb, did you do anything to elminate the rich condition, like decrease jet sizes?

 

[Rob Z]

The carb rebuild was about 3 weeks ago. Used original jets in the carb. Will check the size this week end and advise. What size should be in the original 2brl? I've heard of jets getting pluged, do they get bigger???

The plugs, wires, etc were changed two weeks ago. Plugs were BLACK. Am using motorcraft recomended plugs for the motor.

As of today it still smells rich. Yeserday morning it ran like crap. It was farting like crazy for the first 15 minutes, then cleared out. This was first out of town driving sence all work. Last night around town it felt like it wanted to fart if I gave it hard gas. This morning it farted once or twice then ran fine all the way to work.

 

[garner67]

The carb rebuild was about 3 weeks ago. Used original jets in the carb. Will check the size this week end and advise. What size should be in the original 2brl? I've heard of jets getting pluged, do they get bigger???

The plugs, wires, etc were changed two weeks ago. Plugs were BLACK. Am using motorcraft recomended plugs for the motor.

As of today it still smells rich. Yeserday morning it ran like crap. It was farting like crazy for the first 15 minutes, then cleared out. This was first out of town driving sence all work. Last night around town it felt like it wanted to fart if I gave it hard gas. This morning it farted once or twice then ran fine all the way to work.

While you're working on it this weekend, go ahead and pull one or two plugs again. If the new plugs are already black and greasy looking, the engine is definitely running too rich.

 

[Horseplay]

Don't limit your focus to a rich condition. You need to make sure you have your timing correct and the full ignition system operating well. What you are chalking up to a rich condition could very possibly actually be the result of poor ignition. Make sure you have the correct heat range plugs installed and gapped correctly. Make sure your getting good voltage through the coil, etc. as well.

And no, jets don't "get bigger".

 

[Rob Z]

make sure you have your timing correct and the full ignition system operating well.

OK, you ever have one of those moments where you look in the mirror and say Hello Dummy :craz

I've been racking my brain over this. What could be wrong??? I've checked everything....almost mg

The pertronix syatem was installed about 2 1/2 years ago. A week after that, it went with the kid to Georga for over a year. When it returned is when I started noticing the problem. It never occured to me the problem existed all along. Turns out I wired the pertronix to the + of the coil, which is fed via resistor wire. So, the Pertronix was not getting 12v. It ran OK but not as it should. So, I just properly wired the ignition and DAM if the thing is purring.

I'll know in the next week if this was the problem all along. But my money is on yes o

Thanks Y'all I'll let you know in a few days.

 

[johnpro]

Sounds like another success story!

Question ... what is your plug gap set to?

It's been my experience that with a .032-.035 pug gap, it works fine to run the Pertronix to the + side of the coil. We had a discussion last week, though about not gapping the plugs wider, though, unless you have a full 12v to the Pertronix.

Now that you mention this, though, it does sound exactly like the problem we had with my son's '65 when we gapped the plugs to .040. It worked fine, though, with them gapped to .035.

 

[Rob Z]

They are gaped to .035 Is running the gap at .040 giving better performance or milage?? Why the change??

One thing I noticed was when I used my inductive timming light near the distributer I got good pickup. When I connected close to the plug end I could never get the timming light to fire. Like it had weak spark. That was what sent me to new wires, cap, coil etc. Now that I've moved it to a 12v connection I get good pickup at the plug.

The car ran strong for 2 1/2 years with the lower voltage. It pulled strong and would chirp going into 2nd. I do not 100% know if this has cured my rich situation, but it is ideling much better. I did have to reset the dist as the timming was several degrees off with the new voltage. So it made some difference.

 

[johnpro]

They are gaped to .035 Is running the gap at .040 giving better performance or milage?? Why the change??

Running the bigger gap gives you both. You won't feel a "seat of the pants" difference, but may see a mile or three better mileage per gallon. I'd be inclined, at least for the time being, to just leave them at .035 until you're sure you have everything sorted out now.

I'm going to guess that the resistor wire just has a few more years corrosion now, so is dropping the voltage just enough to cause your problem. My guess is that you have fixed what many of us suspected was a rich condition. A week spark would give the exact same indications of a rich condition.

Good call on Horseplay's part! That guy's got some serious knowledge!!!

 

[Rob Z]

Well after exhausting everything(mostly myself) I pulled the 2brl off and installed the 4brl and manifold off my 70. Now there is no smoke and the car runs like new. So, it appears there is still an issue somewhere in the 2brl that has gone undetected. My thought is eithere a deffective powervalve (althought replaced), a problem in the metering ckt or a failure in the casting which I have not found. In any case I now have a 2brl taking up space on my shelf but a very nice running car

Thanks to eveyone for your help and ideas.