points question, and motor problems.

My car started running rougher the other day. It’s a 64 comet 289/C4, Carter 625AFB, MSD 6A, blaster coil, Duraspark dizzy. Sunday night it ran fine. Monday morning I went to the welding store. I the way there the motor sounded rougher. Like not all 8 cylinder were working or something. Vacuum guage and air/fuel meter looked normal.

At idle, the vaccum guage is smooth. It has always vibrated a little (with these new heads, the old heads- the new lumpy cam, and the old mild one). It behaves totally normal. No funny jumping around or anything.

I tested for spark at the end of each wire with a dummy sprkplug tester. There was spark. Put in new cap, rotor, and plugs. Still runs crappy.

Now I’m going to put in the point dizzy to see if the electronic ignition is at fault. That is where I have my current problem. This dizzy worked that last time I tried it a year or two ago.

Got it in. There were a few very weak sparks when I first cranked it over, then no sparks. Tried a different coil. No spark. Held the coil wire close to a ground, and no spark.

With the points closed and the + side of the voltmeter on the + side of the coil, I get a reading at both sides of the contacts. When I touch the voltmeter to the wire that goes to the coil, I get nothing. This is the connection that is hooked to the movable side of the points, the condenser, and the wire that goes to the – side of the coil. I tested the wire that goes from the dizzy to the coil, and got no resistance. Got any ideas?

I checked the gas for water at the canister filter. I found none.

Anyone have a guess to my first problem??

 

Ok. The - side of coil to wire connedtion in dizzy .6 ohms. - of coil to movable side of points 3.2 ohms. WHat does it mean? Anything??

 

Not sure what you're asking about the ohms?

But points distributors left inactive are best equipped with a new set of points and a fresh condensor before re-use. I've seen it LOTS of times...

"Well, that distributor worked when I pulled it out!"

Drop in a new set of points and a new condensor. Get the points on the cam eccentric (any one of them) and adjust the gap to spec. Once running, you'll want to make fine adjustments to get your dwell to about 28-30 degrees.

Make sure that you are wiring it back up correctly. Hot wire from the starter relay to the battery side of the coil. A 12v feed wire with resistance run from the key to the battery side of the coil. The negative side of the coil goes to the distributor.

Get that MSD paperweight out of the equation and make sure the COIL is good. At this point, the engine should run fine if your problem was indeed ignition related.

You indicated that air/fuel reading remained normal, so I don't think you have a fuel delivery problem. I trust electronic ignitions like I trust Democ...um, politicians in GENERAL! That is, I don't like them...factory systems from GM and Chrysler seem to work fairly well, but the Ford Duzntspark system has always given me nothing but grief!

 

Replaced the condensor and got the points to work. The problem is still there, so it wasnt the electronic ignition. The motor is still vibrating more than normal. I'm gonna look at the mounts a little closer. But the motor doesnt seem to want to rev up as fast.

If i had a cam lobe that was going flat, the vacuum guage would jump around a bit, wouldnt it? I even used a second guage to make sure the first was reading correctly. They both showed compleatly normal readings. That rules out the valvetrain, right?

 

I chased what I thought was a miss in a small block Ford a few years ago...it shook real bad and FELT like it was missing, but what REALLY happened is I put the wrong flexplate on the motor and threw the balance way off!!

Not something that would just up and happen, but something to think about!

 

check the harmonic dampner on the engine, see if it is cracked or loose,

chased what i thought was a bad miss a few years ago, finally pulled engine out to tear down and see what was going on, while it was sitting on engine stand i noticed the dampner was cracked, put a new one on. ran fine

 

Racefab, where was the dampner cracked at?

If it was a balence issue, it would get worse with engine speed, right? This has a sweet spot at 2000rpm and isnt as noticealbe after 3000rpm.

 

It looks like my engine vacuum is around 13in/Hg at idle, and it normally around 15in/Hg when warm. I guess I didnt notice that before. Vacuum guage still acts totaly normal though.

 

Pull the caps on the Carter Carb metering rods and see if one is stuck in the up or partially up position.
That happens when they're bent.
Even very slightly bent.

Check the rods for straight by hanging the short leg over the edge and rolling them on a known to be flat surface - piece of thick glass, surface plate, ground surface of a cast iron drill press table or similar.

The rods can be tweaked back to straight by hand in most cases.

I had one stick in the up position on the rear carb of a Carter 500 cfm dual quad setup.
It ran rough on the low end, would clear out with wide open throttle and some revs up.
I got home ok even with it running rough.

The offending rod looked straight when removed, but it was slightly bent when given the roll test.

 

The motor finally started ticking under the valve covers at idle. Pulled the noisy one off, and the #3 intake rocker was loose. The polylock was almost all of the way off the stud. Adjusted it and locked it down, and it runs good as new

I didnt look under the valve covers earlier because I didnt hear anything but the normal clatter. Really weird that it wasnt making a bunch of racket all of the time.


Picked one of these up from Harbor Freight. Best $3 I have spent in a long time. Now it looks like I know what I am doing