Slant 6 ignition

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halifaxhops said:
Also did this all happen after the points change?
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Hello Dr Hoppy,
The symptoms of the #6 and #1 plug wires not showing up on the timing gun flash was happening before the points change. I was a little scientific in that I did one change at a time and started car in between changes.

car runs like shite........took out and tried to "clear it out"

clean plugs........a slight but noticeable change in the right direction (if I even remember correctly)

still running like shite.......change points and condensor but use matchbook to gap points (possible error)

At this point it seems like I have added a "no spark in the wire" condition on #1 (not just #6) that has now persisted. (#6 will fire intermittently with an RPM increase)

Change cap n rotor..........Shite

Final result as of walking away yesterday eve is ........#6 and #2 are intermittent spark with RPM, and no spark at idle. #1 cylinder no spark condition all the time.

Thanks to you all for the time and knowledge you have given me.
 
Dave999 said:
id do the following
might not help but doesn't cost nuffin

clean the ceramic part of each plug in brake cleaner or even dish soap and water
squeaky clean.. if the electricity can track across the ceramic in the dirt you get no spark

clean out the connectors on the ends on the wires in a similar way. dirt in the rubber boot can do the same thing.. well it can in damp wet places like where i'm from

make sure the screw on parts on the plug tops are tight if they need to stay in place for your leads.

try a spare or different set of leads...


if that doesn't help this does cost a bit

i have one of these (sadly sold out on your local website, but decent info)

Gunson Colortune See Through Spark Plug Kit G4074 G4171 G4172

its a see-thru spark plug with a little telescope and mirror so you can see the colour of the flame in the chamber..

dismissed by many as a waste of time. but hey there is no convincing some
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Thanks Dave,
I have one of those inline deals that Ill see if I can visualize the spark.

I think a plug check might also help
 
Cap. Almost a 1/4”….. probably in the 3-16” side. They all have a tiny bit of carbon streak across the face. Arguably #1 and #6 MIGHT be a bit cleaner. Again, a new cap ran for 5 min +/-

Batt seems low.

image.jpg
 
Bewy said:
Swap some plug leads & see if the problem moves with the leads.
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I did swap the #5 wire to the previously not firing #6...........#5 still fires and #6 exudes the same symptoms.

Are there any grounds that I need to be aware of in this scenario? It is just the spark plug itself no? (grammer?)
 
Circling back here.

As expected 1, 2, and 6 plugs are black.

3, 4, and 5 look like they are a bit cool

Plug order is 1-6 right to left

I have new plugs n wires which I’ll install.

Check lash.

IMG_1926.jpeg


IMG_1927.jpeg


IMG_1928.jpeg
 
6 new plugs and new wires and she fired right up and is running good. Still doesn't fix my problem though. It was running good before and I don't believe the hardware I took out was that old.

So why do 1, 2, and 6 look pig rich?

3, 4, and 5 only have grey halfway down strap.

You would think the interior plugs would be richer than the long runner outsides ya?

My compression checker is MIA.

I will clean up some grounds especially on the headlight circuit. I have a spare one of those relay harness' made by crackedback that will help. The headlights are real dim.

This car will be going up for sale pretty soon to support my pre war project I picked up. I'd like to get it going as good as I can.

Thanks FABO!!

Lots of reading from SSD to do!!
 
Nope, not hotter plugs. There are '4' s in there now, which are already a hot plug. The fluffy black spark plug electrodes suggest a very rich mixture, such as the choke partially closed.
 
clementine said:
Circling back here.

As expected 1, 2, and 6 plugs are black.

3, 4, and 5 look like they are a bit cool

Plug order is 1-6 right to left

I have new plugs n wires which I’ll install.

Check lash.

View attachment 1716385173

View attachment 1716385174

View attachment 1716385175
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You are faulting the ignition when the carb is so pig fat Rick it’s no wonder it’s dropping holes.

Get some fuel out of it go from there. You are way too rich and it’s not even close.
 
Newbomb Turk said:
You are faulting the ignition when the carb is so pig fat Rick it’s no wonder it’s dropping holes.

Get some fuel out of it go from there. You are way too rich and it’s not even close.
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so on a single barrel carb, how many jet sizes should i drop?
 
clementine said:
so on a single barrel carb, how many jet sizes should i drop?
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I have no idea but you have to get some fuel out of it. I’m sure there are plenty of guys on here who know way more about those carbs than I do.

Could it be getting fuel from an internal leak or something?

Bad float?

Leaking needle and seat?

IDK but if the jet sizing appears to be normal or close to it, I’d suspect another issue. Maybe the fuel pump is now producing too much pressure. I’m just spitballing because that’s all I got.

Also, if you had an ignition other than points it would probably fire those dirty plugs, or at least not miss as bad.

That’s one bad thing about high power ignitions. They will cover up a bad tune up.
 
Even if the plugs were fouled, you would get current on the plug wire, indeed more since now shorted so no gap to jump. I would keep poking at the "no timing flash when clamped on spark wire ##" issue. I use a timing lamp as a quick way to test my newer distributorless engines too. On my 2002 Chrysler 3.8L, I quickly found a misfire was due to the #2 and #5 wires not flashing the clamp-on lamp. Both come off the same coil pack, which sits closer to the engine (hotter) and I could hear a faint clicking inside. Swapping in a new coil-pack fixed 'er.

Re dwell, it is controlled by the points gap. A matchbook cover is correct thickness for an AC clutch gap, but don't recall if correct for a points gap. I recall that is 8 mil spec, and why many feeler gage sets have that size in brass (non-magnetic). Ideally, after setting the points gap roughly with a feeler gage, you then measure "dwell" with engine idling, then tweak points gap until you get dwell in-spec. What dwell adjusts is the time that primary (12 V) current flows thru the coil, when points are closed, to recharge the magnetic field. The longer recharge time the better, but if the points gap is too small, the current will jump the points gap to not break the current and cause an HV spark. The ballast resistor is also involved, by throttling current at lower rpm to not overheat the coil (something like that, forget).

If you tire of fooling with points, there are many posts on retrofitting 8-pin GM HEI ignition, using a 1971+ slant e-distributor. The 8-pin is best since rugged connectors and can use the GM coil with its cable to module, so just need a few wire hookups. Also has a connector that some later EFI boxes can use to command spark timing (ex. Holley Commander 950). Photo of that on my 1964 slant. Simpler and easier than wiring in the Mopar electronic ignition stuff. BTW, I also ran the heater hoses on the inner fender (instead of valve cover) and added a water valve (generic) to halt heater flow when the AC (retrofit) is used.

HEI-small.jpg
 
I had a problem once where the plastic gear on the bottom of the distributor shaft was bad and jumped a tooth it ran terrible
 
RustyRatRod said:
Lots of reasons to run rich besides jets that are probably not at fault.
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Which would be the top three you would chase down in order?

The car will be going down the road soon but I like to sleep at night so I want to do my best to give her away running right. I bet the next person swaps it for a V8 but ya never know. It handles flat through the corners and is quite fun to drive.
 
clementine said:
Which would be the top three you would chase down in order?

The car will be going down the road soon but I like to sleep at night so I want to do my best to give her away running right. I bet the next person swaps it for a V8 but ya never know. It handles flat through the corners and is quite fun to drive.
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Well you can kill two in one shot by inspecting the float to see if it's compromised and inspecting the needle and see to see if it's sealing properly. Nutball in post #40 already mentioned those. It's a ONE BARREL carburetor on a SLANT SIX. It's highly unlikely it needs to be jetted down. The much more likely scenario is that something's wrong with the fuel system. Maybe trash in it for example. These old girls are notorious for getting rust and trash in the fuel tank. Have you ever had it out and cleaned it? It needs to be done I'd say once about every three years considering this crummy fuel we have to put up with. I'd get the carburetor off and get the top off and inspect it. I suspect you'll find the issue, as trash in the carburetor and or compromised floats. That won't be the source though. The fuel tank will be. Remove it, clean it, blow all the lines out, replace all the rubber hose int he system with Gates rubber EFI rated hose.
 
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