Me and the Meadowbrook

[keithb7]

For me, the Pentronix would definitely be a prime suspect. I've never owned one so I can't be 100% sure. If it were my stock ignition system back firing, I'd be be checking points, condenser, coil, cap, rotor, wires, spark plugs and all connections. Mechanical and vacuum advance.  You have done some of the right things already. Have you checked all your wire connections to the Pentronix? Any frayed? Loose? Possibly grounding out? 

[Worden18]

2 minutes ago, keithb7 said:

For me, the Pentronix would definitely be a prime suspect. I've never owned one so I can't be 100% sure. If it were my stock ignition system back firing, I'd be be checking points, condenser, coil, cap, rotor, wires, spark plugs and all connections. Mechanical and vacuum advance.  You have done some of the right things already. Have you checked all your wire connections to the Pentronix? Any frayed? Loose? Possibly grounding out? 

I have not checked the pertronix connections; should have been the first thing I did.  Dang fool I am!  Also, I wonder if the wires/ground inside of the dizzy are loose?  Answer this Keith, do I need an extra ground strap from engine to frame?  Tomorrow I'll follow up on your suggestions.  Thanks

[keithb7]

An extra ground wire can help, but no, not required. I don’t run an extra ground wire on either or my cars. However nor do I run Pentronix. So perhaps someone else will chip in. 
 

Be sure to also check any mounting bolts or any other type of anchor systems are tight for all Pentronix parts. 

[Sam Buchanan]

text deleted

Edited May 1, 2020 by Sam Buchanan

[Dan Hiebert]

Backfiring tends to be caused by the car running too rich, delayed timing, or cracked distributor cap.  I.e., too much unburnt fuel in the exhaust (rich), or a cylinder(s) firing when exhaust valve is open igniting unburnt fuel in the exhaust, rather than in the cylinder (timing, cracked cap).  You may have both (too rich / timing) going on for that big a bang.  The burning of the leads in your distributor cap - where they are burnt, at the outer edge of the lead, vs. somewhere along that flat plane - looks significantly delayed.  Adjusting the float will not help, you need to check the air/fuel mixture.  So, timing and air/fuel mixture should be checked first.  If you have not monkeyed with either since that rebuild 4 years ago, those could be the culprits.

Edited May 1, 2020 by Dan Hiebert
Typo

[Ron175]

I’m having a similar problem with mine - I’m running a Pertronix too. Backfired so bad it did blow out my muffler! My coil and module tested fine. Vacuum readings are low indicating late valve timing and plugs are sooty, but everything seemed ok until recently. 
I’m interested to see what you find out....

[Sniper]

A misfire goes out the exhaust.

 

A back fire goes out the carb, you know backwards from normal, hence the back in backfire.  Might be a minor issue, but words are all we have here and the solution for each issue is not the same.

 

That said, sounds like you have an ignition issue.  Had something similar happen to my 64 300, turned out a plug wire had popped off a plug and the unburned fuel was getting ignited in the exhaust.  Muffler looked similar, after all it was essentially a mini air/fuel bomb going off.

[lepic56]

HI

The distributor cap worried me.. All the firing was made from the right side of the wire tower,  even the contact at 6 o'clock is almost new.

Look like the rotor is sending the firing voltage just before it line=up with the wire contact..

Maybe to much avance or retard on the timming of the firing..  cause by ??   maybe , like keithb7 said .. you're  Pentronix  system as something or it simply  off center on the sub-plate and plate ?,   or  bad static timming ?

anyway let us know what you find,, 

 

[Los_Control]

My brother had a mid 60's baracuda with a slant 6 he drove as a daily driver/work car years ago. Driving home on the freeway it misfired and died. Actually blew the dipstick out of its hole.

He sold it to a co-worker for $100. Co-worker came over and looked at it, went to parts store and bought a distributor cap, installed it and drove the car home.

 

You get a aging distributor cap and can cause much grief. A hairline crack and spark will choose easiest path through the crack.

Then with the quality of todays ignition parts, age is not really a factor, as new can be bad out of the box or last for a short time.

Just something to inspect closely.

[Bbdakota]

4 hours ago, Los_Control said:

My brother had a mid 60's baracuda with a slant 6 he drove as a daily driver/work car years ago. Driving home on the freeway it misfired and died. Actually blew the dipstick out of its hole.

He sold it to a co-worker for $100. Co-worker came over and looked at it, went to parts store and bought a distributor cap, installed it and drove the car home.

 

You get a aging distributor cap and can cause much grief. A hairline crack and spark will choose easiest path through the crack.

Then with the quality of todays ignition parts, age is not really a factor, as new can be bad out of the box or last for a short time.

Just something to inspect closely.

I agree! Also, could the dizzy have rotated? Maybe put a light on it.

[DJ194950]

Check voltage to coil-connection tight both coil terms.

 

Air gap on the Pertronix setup correct?

 

DJ

[Worden18]

To everyone whom replied and gave advice: THANK YOU!  I will do some checks and inspection and let you guys know what I find.  Hope to get out there this evening...

Edited May 1, 2020 by Worden18

[Worden18]

5-1-20:

Okay fellas, I checked all connections to the coil, distributor, pertronix, etc.  All were tight and looked good.  I unhooked the vacuum advance at the distributor because that is a hard line that doesn't move very easily.  Then I was able to loosen the distributor and move it. It was pretty much almost all the way advanced.  I know that I initially had it slightly advanced, but not that far. I don't know if it worked its way to a farther advanced position. It must have.  Anyway, I don't have a timing light. So I just turned the distributor back about halfway. The car started right up. I discovered I did blow my muffler, it was pretty loud even at idle.  But the engine sounded great!  I let it run for a little while with the choke slightly closed, and then with the choke fully open.  It ilded  nicely, then I shut it off.  It started back up with no issues several times.  So I'm happy with that.  But I'm not going to risk driving this dragster sounding jalopy in the dark and wake all the neighbors.  I'll give it a test run in the morning.  I suppose I should give it a good run even with the crappy muffler?  No sense blowing out a new one if the problem isn't solved.  After all, it was under a load that it misfired like an A-bomb.  ?

But yes, so far you guys were right in saying the timing was far advanced.

[Worden18]

5-3-20:

I reset the float.  Not quite sure how far off it was, but my manual only gives reference to Stromberg carbs, mine is a Ball and Ball.  I watched a video on YouTube from Mike's carburetors.  Now I got that pretty close.  Test drove the car.  No misfires, etc.  Ran much better than before.  Has some chugging to it now; you can barely feel it.  Maybe the timing is too far retarded now.  I'm going to mess with it some more.  But no doubt the timing was far advanced, and that was the biggest problem.  

[Worden18]

I can't seem to time this car by ear.  Call it operator error, inexperience, or whatever.  I talked to a friend about what some of you guys have mentioned: timing it with a vacuum gauge.  He said that's all he's ever done. I need to buy one first.  Biggest question I have concerning the gauge: where do I hook it up?  The car has electric wipers so I can't go there.  I've never used a vacuum gauge before but I want to try it.  My friend had mentioned hooking up to vacuum wiper line... I forgot I had electric wipers until long after we hung up ?

[Dodgeb4ya]

There should be a 7/16" hex plug on top of the intake manifold at the rear near the firewall.

Hook up the vacuum gauge hose at that point.

[Bbdakota]

If you've got to buy a tool anyway, you'll be money ahead buying a timing light. Even after timing it with a vacuum gauge, you still should check it with a light. My 2 cents.....

[Worden18]

53 minutes ago, Dodgeb4ya said:

There should be a 7/16" hex plug on top of the intake manifold at the rear near the firewall.

Hook up the vacuum gauge hose at that point.

Okay thanks man ?

[keithb7]

A new generic readily available timing light will be 12V.  It can used by hooking it up to any 12V   battery. A spare car parked beside you is fine to hook up to. A ride-on mower or motorcycle battery is also just fine. Just hook the inductive clip on your car’s  #1 plug  wire and pull the trigger on the gun while pointed at your spinning harmonic balancer. 
 

I’ve not used my vacuum gauge to set the timing before. I might try that soon and post my results. Before and after vacuum-readings would be interesting. Cool thing is the vacuum gauge also doubles as a fuel pressure gauge. A good tool to have. 

[Adam H P15 D30]

Most of the Pertronix modules I have dealt with are garbage and eventually will leave you stranded with replacement parts days away.  That said, I have seen them act exactly like you describe when they are on their way out.  First indicator was the timing was all over the place, backfiring, popping mufflers etc. and eventual death.

FWIW....

 

On Edit:  Looking at the picture of your distributor cap, it clearly shows the coil is firing when your rotor is NOT lined up.  Cut a hole in the cap next to a post and point your timing light at it, you will be able to see the improper timing.  The rotor timing is different than ignition timing. 

Edited May 4, 2020 by Adam H P15 D30

[Dodgeb4ya]

2 hours ago, Adam H P15 D30 said:

.  The rotor timing is different than ignition timing. 

Could you explain exactly why and how the rotor timing problem occurs and how to correct it?

[Sam Buchanan]

The cap has an indexing key, wonder if it is smaller than the notch in the rim of the distributor? That would allow the cap to rotate so the rotor and terminals don't clock properly.

[Adam H P15 D30]

55 minutes ago, Dodgeb4ya said:

Could you explain exactly why and how the rotor timing problem occurs and how to correct it?

I learned about this when a friend tried to use a point distributor to trigger a GM HEI module.  The module would fire when the points closed instead of opening causing the spark to happen when the rotor was between the cap towers.  Seeing these Pertronics modules really mess with timing when they are dying and the picture of the distributor cap brought back that memory.  It's like if the point cam was out of time inside the distributor.

Worden has put a lot of time chasing what could be the problem and seeing that the timing magically changed all of a sudden on a car that is driven a lot leads me believe the Pertronics is the root cause.  At this point I would drop a set of points in it, time it and see what happens.

 

Hope this helps....

Edited May 4, 2020 by Adam H P15 D30

[Worden18]

Thanks for that info Adam, I will keep this in mind.  And Sam, the male/female notches in the cap and on the distributor fit nice and tight.  No movement.  I have a couple of extra distributors lying around, if one of them matches the existing one I'll put together a points set-up and pop in in for a test run.

Edited May 5, 2020 by Worden18

[Adam H P15 D30]

Hurry up Worden, I miss your drives and pictures!