230 rough idle help

[gotzskillz]

Ok, so long story short, I rebuilt my carb and installed new plugs, points, condenser, rotor, and cap. I did this because my truck was running rough and I wanted to be sure I would be fine later down the road. Now my truck seems to run worse. From what I can tell it sounds like it's missing on some cylinders or not firing at all.

I'll be honest, I'm good when it comes to just about everything accept when it comes to ignition diagnostics and tuning.

So what I'm asking of yall is if you could provide me a list, in order, of what to check to try and trouble shoot the issue. Procedure would be nice as well but I could look it up in the manuals.

Also, valves could probably use adjustment but I don't think that would affect the idle.

Please help and I look forward to your responses.

[Don Cavey]

"Back in the day" these trucks suffered from leaky valve seals. The one that I drove in Germany would foul a plug due to oil consumption. The engine would shake and be lacking power.

What I did was to take the dip stick, place about one drop of oil on the exhaust manifold very near the head and then start the truck. The non-working cylinder would not burn off the oil right away. Crude but it worked.

So for ignition:

-I would make sure that the points are gapped to the proper spec. From the online manual on this site: Adjust contact gap from .020” plus or minus .002”.

-Plug gap: "Use a round feeler gauge and adjust each spark plug gap for .030-inch."

-Make sure that the plug wires are in the correct order. Usually, the truck won't even start if they are wrong. The firing order is (from memory)1-5-3-6-2-4 and they rotation of the distributor (from memory) is anti-clockwise with #1 being at approximately the 1-oclock position.

-Timing should be 5 degrees BTC (Before Top Center). That can be a little difficult because you need some kind of an adapter to go in series with the #1 plug wire.

For the carburetor, I had one that came with my truck. I was suspect because it had the metal wire with a stud in it going across the opening of the throat. That sure seemed to be from a Chrysler slant-six engine! That carburetor did not idle well and hesitated way too much. I got another core and rebuilt it and it is just fine now.

These engines don't have vacuum advance, only mechanical. So if you have had the ignitor apart, make sure all of the parts were replaced properly and that the weights in the ignitor are not stuck or installed incorrectly.

Here is the reference from our online manual:

http://www.m715zone.com/vb/view.php?pg=20chap2-14

[67U20]

As Don said, Oil fouled plug(s). Have the same issue, No5&6. Clean them it runs fine, shut it off an let it sit. Next start up the leaked oil fouls them out.
Got a good head ( ovh'd) to install as soon as I can get a few other projects
either completed or at least manageable....
Valve adjustment can affect idle. Too loose or tight will affect valve timing, compression. An engine's weakest point is idle as it does not have the power and inertia going to carry it through any 'flat spots'.
Mine has a civvy distributor so is vacuum 'advance', ( which is actually a misnomer...)

[wolf.dose]

Hey Don,
the firering order you mentioned , is correct. All straight six have the same firering order. Else they do not run.
You can stick that to your mind with: 15 to young, 36 to old, 24 just right (related to a women's age).
Not firering cylinders you also can spot with taking out the spark plugs and just put your nose over them. The non firering / poor firering cylinder smells from unburned gas.
Hope this helps.
Wolf

[md1970]

I,d remove the valve cover and check the cam lobes and valve clearence. if your engine still has the stock oil line to the rear of the head I bet you,ve ate a cam lobe ot lobes hence the rough idle.
M

[gotzskillz]

Thanks everyone. Unfortunately I've been working every day since Monday and don't get some days off till Thursday.

I'll check what I can then. I'll have to get a new gasket before I pull the valve cover.

I want to check dwell as well but the meters I have have to be connected to a 12v battery and the coil, so I don't see a way to use them on my truck.

[CRNA]

Like stated above, check the order you put the plug wires back on. I have no doubt you put the plug wires in the 1-5-3-6-2-4 order but did you count clockwise or counterclockwise?
In a chevy engine, you count clockwise but in your case, count firing order counter clockwise.

The reason I say this, I changed my wires points, cap, etc... just as you have. I also had the misfiring and no fire in different cylinders. When reinstalling the plug wires, I ran the wires clockwise like I have done on all my CHEVY rebuilds (big, time consuming, and stupid mistake). It took me 3 days to figure out what I had done wrong.!!!>

Hope its something this simple for you