1968 Jeepster Commando With A Coughing Dauntless V6

Hi to you all,

Some Months ago I bought this 1968 Jeepster Commando with a dauntless V6:

The sellers were so kind to offer home delivery (, a 100 Mile ride; I should have suspected something at that time...).
Of the trailer the Jeepster ran ok, although it started without using the choke which I thought was a little strange and smelled quite rich (unburned fuel). I also found the idle too high.
I drove it around for some 15 miles that evening and everything looked ok. I used the idle adjusting screw on the throttle cable near the carb to lower the idle to about 700 rpm.

The next morning I had a hard time starting the engine...I used the choke but that did not seem to help. Afraid that I must had ran out of fuel I quickly went to the nearest gas station to fill her up.
The coughing got worse and she would only stay alive by pushing the throttle constantly. I drove around, barking big black clouds of smoke. Back home I fidled around with both the idle mixture needles in the front of the Rochester 2G carb as well as the idle screw but did not get it to run properly.

I decided to replace the spark plugs, rebuild the carburetor (ordered a kit at MikesCarbs) and replace the external fuel filter which was placed by PO between fuel pump and carb. I let out some fuel at the drain plug of the fuel tank to see if there might be water or rust in the tank but besides a few black bits (smaller than grains of sand) the fuel seemed clean.
While rebuilding the carb I discovered that the internal fuel filter was missing. I ordered that part as well together with a new bras float.

After putting it all back together the Jeepster ran quite well. Starting was with full choke, which I would open after 30 seconds. She would start right away, than in the mid rev range would run a bit low on power and with full throttle would gain a little power (did not feel like 160HP at all but than again after 90,000 miles and 48 years...what can you expect).
The plugs were grey white, indicating that the mixture was to lean. Since I was struggling a little with the imperial measuring, I'm not used to inches, I did not adjusted the float according to the manual that came with the kit.
Maybe the wrong float drop caused the engine not getting enough fuel so I converted the inches to millimeters and adjusted the float. That did not seem to make too much of a different.
Time to fill her up again; Again the same issues as with the first time I refueled the tank.
My next guess was that both the fuel filters were still not filtering the fuel completely so I opened the carb again to clean it (maybe 2 or three little particles) and used an auxiliary fuel tank with the next test run.
That did not seem to help much. Again big black clouds and no power, stuttering and stalling engine.
Next thing I suspected was the ignition.
I replaced the coil with a Petronix Flame Thrower and converted the points to a Pertronix ignitor.
I made an error putting the distributor back on so I used a timing light to find the right setting on the gear.
After starting her up this looked like the answer to all my problems. The Jeepster started right up using the choke. It ran a lot better, feeling more powerful and no black clouds. The spark plugs did look quite black though so I made an attempt to tune the carb, using the idle needles and throttle adjust screw.
Time for another refill to get some idea on the MPG... Again the same issues, stalling engine, big black clouds.
Back home my neighbor suggested to take of the air filter to look at the choke valve. Good suggestion that proofed to be, the cable operating the valve did not work properly, leaving the valve half closed. That would explain the unburned fuel, too little air.
Readjusted the cable and the choke was fine again. Jeepster was running quite good again. Got the mixture leaner without compensating on performance... I was getting there I thought...

Filled her up again just to check.. AGAIN same issues.
Now I am back to suspecting the fuel tank again, there are some white flakes in the external fuel filter that look like teflon tape...

The engine runs not too bad at the moment but now and then coughs a little, I am not to sure about the fuel economy but do not thing I get any near the 15MPG I have been reading on several fora. She still smells too rich and the spark plugs are black.

Is there something I am missing or is the next thing to do replacing the tank?
What can I expect from a 48 year old dauntless V6 with aprox 90000 or so on it? Both in MPG and performance?

Do you tips for further investigations, improvements, maintenance?

I look forward to your input and apologize for the lengthly text and grammar.

All the best!

Rauw

 

Just to ad some more info: There seems to be missing a hose from the choke to the vacuum. Not sure to leave it this way, order parts to reconnect it or just block it by putting a fuel line with a stop in it:

 

Do you have the vacuum hose hooked up to the distributor? Is it coming off the ported side of the carb?
Is your float plastic or brass? If plastic make sure it is actually floating. Ethanol will attack the old plastic floats.
Have you check for vacuum leaks around the carb throttle plate?
What setting are you using for the timing?
The original data plate on my jeep (71) had the timing at 0 degrees, 650-700 rpm, lean best idle, 30 degree dwell. Yours should be similar. My 71 originally had a prestolite distributor, and it had the smog pump which means the ignition settings where different than earlier models. We switched it to the delco-remy distributor and ran it at 5 degrees btdc in 78. It ran perfect at those settings. Now I have an HEI and run about 8 deg btdc.
If my jeep had the same symptoms I would verify all the timing settings (set with a warm engine) then take apart the carb again.

 

Hi Grant,

Thanks for your post!
The vacuum hose (in the second picture hanging loose under the choke cable) is coming out of the outlet between the choke housing an fuel inlet and connected to the vacuum control on the distributor. Is that the ported side of the carb?
The original float was Nitrophyl and after rebuilding the carb and still experiencing issues I replaced it with a brass float.
I have not checked for vacuum leaks, is there an easy method to do so? The gaskets are new and should be ok but always good to check I suppose.
I use 5 degrees btdc at 650 - 700 rpm. After your message I rechecked with a warm engine and it was 10 degrees btdc. Most likely the engine was not warm when I set it the first time. Engine seems to run a little better now. The distributor is a Delco and I put the Pertronix ignition in it.

Any ideas on the vacuum outlet beneath the choke cable? Since I do not have any idea what should be on there is it better to leave it open or put a stop on it?

Thanks

 

My petrol tank is half empty now. I am thinking of driving some more and than drain it, take it of and rinse it... Is this likely to solve the problem or just a waste of time? Anyone?

 

Looking for answers on this forum I came across this thread: 225 running rough

I quote: "Look inside the distributor, under the rotor. If there are three "points" on the distibutor shaft to trigger the HEI then it is an odd-fire distributor. The corresponding "trigger" points on the ignition module inside the distributor will be unevenly spaced on an odd-fire, and evenly spaced on an even-fire engine."

I immediately ran to my Jeepster, opened the hood and took of the distributor cap:

Could it be the PO installed a wrong distributor/cap? Or does the story above only applies to
delco hei distributors?

 

Browsing the interweb some more and stumbled across this thread: odd firing oddfire? - Off-Road Forums & Discussion Groups
This guy has EXACTLY the same issues as I am experiencing with the Dauntless and the cure ended up adjusting the dwell of the points...

One big difference, in order to solve the problem I replaced the point with a pertronix ignitor... Will looking at the "dwell" of the pertronix do any good? Some say no, some say yes...

 

Well, took me a while, but better late than never. This is where the vacuum line should be connected.

 

My dauntless has a vacuum port on the intake, you can attach a vacuum gauge there. Or attach it to that ported vaccum port on the carb shown above.


Here are some good links about vacuum:

Distributor Tuning and Theory - Part 1 - Hot Rod Forum : Hotrodders Bulletin Board


Technical Articles: Engine testing with a Vacuum Gauge - at Greg's Engine & Machine

 

Thank you! I will read them tonight and hopefully find some answers.

 

I share in your behaviors of your Commando with my daily traveler, "Fussy", my 68. That's exactly why I named him Fussy, there's that point between choke going off and fully at operating temperature when Fussy will stutter a bit on acceleration. If I hit the throttle too quickly, I can get a backfire in the carburetor. It's at it's most tolerable level possible after some checks and tweaks considering the cause - Bad intake gasket on the right side up front. Spraying some carb cleaner there caused it to almost stall. Was the last thing I checked.

Fussy stumbled real bad when I first got him going road-worthy. First I rebuilt the carb. When I checked the float I found it had too little drop, so the fuel had little room to fill the carburetor. My rule of thumb on float settings is this:
With the float and needle installed, hold the air horn (top of carb) upside down. Eyeball the float. The highest setting I've ever seen rebuilding over 300 plus carburetors over the years is parallel with the surface of the air horn, so that's my go-to setting on a stumbling engine. Fussy was lower than that (further away from the parallel). Drop is as important as height when setting the float. My rule of thumb on drop is to set the float drop so that the lowest point of the float cannot touch the bottom fuel chamber of the carb (measure fuel chamber depth and with the air horn correct side up and level, make sure lowest point is less the your measurement..

With that done, things were noticeably improved, but the problem was still present. Second, I checked the points (perfect set- no pitting) and checked the dwell (spot on). Not a problem.

Third I checked the timing, which was 2 degrees retarded. Corrected to TDC. Again, noticeable improvement, but still just not 100%. I couldn't just step on the gas and go without a hesitation.

That was when I checked for and intake gasket leak. It's a steel gasket, go it can fail from rust or corrosion. I found my leak to be external and small, but the gasket can also leak where it's internal.

Until I get to the gasket replacement, I did the fourth thing - I adjusted the carb mix to compensate as best as I can get. Put a tach on the engine when it's fully warmed to operating temp. Verify idle speed is to specification or desired speed (700 to 800 is good for stick shift). Turn in one mixture screw in until it stumbles at idle. Then back off about a 1/4 turn at a time of 15 second intervals while watching the tach. As you back out the adjustment, the RPM should rise. Eventually, it will stop rising. At that point back in until you see the tiniest drop in RPM. That is the setting. Repeat on other side. If the idle gains too high, turn down the base idle screw and adjust again - both sides! I've had carbs where that process needed to be repeated two or three times to get the setting perfect.

If there is no RPM change moving mix screw adjustment, passage is clogged. Sometimes only one side works and one side is clogged.

If I leave my choke on slightly, I have little symptoms of hit-the-gas stumble, but of course bad mileage when you do that. Sounds like you have the same issue my 68 has.

 

That all sounds really familiar... Especially that many steps do give small improvements but still not enough. Thanks a lot for giving me all this extra info, will continue my search and will focus on the carb adjusting and possible intake gasket leakage.
I wish I could drive another jeep with a Dauntless V6 just to get some idea what to expect but unfortunately I do not know any.
I do have a M38a1 with a hurricane engine and the performance more or less equals that of the Jeepster. Is that ok given the extra weight of the Jeepster or is the V6 underperforming? Milage is horible, mayby 7-8 MPG...

 

That is pretty bad. I get about 13-14 mpg. And the v6 is much stronger than the hurricane. Have you done a compression test? Are the distributor wires going to the correct cylinders?

 

I think I would start with the basic stuff first, rule out the easy stuff, do a compression test, do a cylinder leakage test, put a vacuum gauge on it and read what is says as you open up the carb, if everything is still good, make sure you have an odd fire dist in there as well as cap, real easy to mix it up, make sure it is wired right and good wires, correct plugs, no vacuum leaks around the carb or intake. An old test I have done before is if you squirt gas in to the carb as it is running and revs up you have a vaccum leak, if it drops down in revs, you do not?

What else guys?

 

I'll order both a compression test set and a vacuum meter to start testing.
The spark plugs are new and the right type, the gap is good, I converted to Pertronix Ignitor and get a great spark. Timing is set at 5 degrees BTDC as a Delco Distributor should be.
I tried to take the rotor of to identify the distributor but unscrewing the two little bolds and taking it of did not give the insight I was hoping for, any tips? Should I do it again and make some photo's?

The wires are in the right order, triple checked.

Pulling number 2, 4 or 6 does not seem to have the same impact on the idle as pulling 1, 2 or 3. I will check this again to be sure because the engine stalled, probably no fuel left...

Thanks all for the advise, I look forward to a proper running Dauntless!

I'll keep you posted on the progress, if any

 

As for economy, the records I have suggest ~15mpg is typical for the 1967 CJ5 I have (dauntless). Your vehicle is a bit heavier but with the hard top it's actually more aerodynamic so I'd say mid-teens if it's running right.

 

Ok, so I know where to aim for now... thnx!

 

Pulling the even wires and not having the same effect as the odds indicates to me you have an internal carburetor blockage or the adjustment is way off. Either sides' wires should drop the same RPM when pulled.

 

Ok , Today I received both a vacuum tester and a compression tester: I performed a compression test first:

Cylinder 1: 95
Cylinder 3: 115
Cylinder 5: 118
Cylinder 2: 118
Cylinder 4: 120
Cylinder 6: 113

I dropped a bit of oil in Cylinder 1 and got 98/100.

I again tested the wiring of the spark plugs. So next thing will be a vacuum test. I wil read into that and after I have done it, share the results.

I did not buy a cylinder leakage test, should I?

 

This morning I hooked up the vacuum meter to the inlet manifold (the hose normally connected to the power brake). The reading was aprox 15 suggesting timing was to late. I loosened the bolt holding the distributor a little and advanced timing until I got a vacuum reading of 20. What a different, idly all of a sudden is really gentle, not nearly as rough as I thought a Dauntless should be. I made a test drive and the car seems to have more power, runs smoother and quieter, I still feel I need to adjust the carb better but this is quite an improvement.
What is odd though is that timing is at 15-20 btdc. What does that suggest?

Furthermore the needle of the vacuum gauge is trembling about 1-2 mm both sides, does that indicate worn valve guides?

I'll post a video of the vacuum this afternoon (gmt+1 ) after I have tingled some more with the carb adjustment.