What is causing my misfiring while driving ?

[Evan Frucht]

On your points, are you putting a dab of grease under the lip of the points block? this is the space that as the points go over the cam it is constantly getting a tad of lubrication. If you did not lube this area, the point block will wear down pretty quickly. Compare the set you just took off to the new set.
Is your engine wiring harness original to the car? Or has it been replaced?
Dealing with 56 yr old wiring is a crapshoot at best considering these cars were never meant to be on the road this long. Something to think about.

I did actually. But oddly enough I think that whatever solvent they used in the random tub of grease I decided to dab my finger in, might have accelerated the wear. Either that or the points that came with new distributor were simply total junk. They did look a little flimsey/cheap and the cam was made out of what looked to be some kind of brown fibrous material... the new napa points have a solid plastic cam... something I noticed..

The wiring harness is mostly original but I have redone the bulkhead and replaced all the bad wiring.

 

[Slap Stick]

Condensers these days are crap. I've seen the insides where the case, which is the negative contact-is not mechanically connected to the guts. They fail-without fail. Good condenders rarely fail. Its just a capacitor with a metal case.
On my motorcycles which use points I bought some Condensers, which IIRC were for a Ford truck. I think the value was .27μf. Sho nuf on a trip back home from VA one cylinder stopped firing. I carry a multimeter, so I tested the condenser. Swapped it out and I was back on my way.
If you still have an old condenser cut it open and see if the internal connection is mechanical or just a contact.

 

[Evan Frucht]

Well its fucked again as of about a week ago. Was trying to tune it and then eventually it somehow went to **** and won't run right anymore. Idk what is wrong/ how serious it is/ or what I can do to narrow **** down.

It was running fine and reliably for years/ months, now I can't trust it.

 

[khryslerkid]

You might try checking the spark that you're getting while cranking. If it's a weak spark then it could be the condenser, coil, points gap.

Make sure the wire to your points is in good shape. They are known to be bad where it comes through the distributor. Could be old and corroded inside and you don't see it. Rig up a temporary wire to check or use a ohms meter and bend the wire while watching your meter.

Make sure the point's insulator is good and not grounding. Use ohms meter to check.

Make sure you have good grounds on the engine. Battery to engine. Engine to firewall.

Bring the cam up on the points and check side play in the distributor shaft. Too much could be changing your gap that you set. Watching a dwell meter while changing the rpm of the engine can show excessive distributor shaft play.

Determining whether it is a ignition problem or fuel is your goal.

Just throwing some things out there.

 

[Evan Frucht]

You might try checking the spark that you're getting while cranking. If it's a weak spark then it could be the condenser, coil, points gap.

Make sure the wire to your points is in good shape. They are known to be bad where it comes through the distributor. Could be old and corroded inside and you don't see it. Rig up a temporary wire to check or use a ohms meter and bend the wire while watching your meter.

Make sure the point's insulator is good and not grounding. Use ohms meter to check.

Make sure you have good grounds on the engine. Battery to engine. Engine to firewall.

Bring the cam up on the points and check side play in the distributor shaft. Too much could be changing your gap that you set. Watching a dwell meter while changing the rpm of the engine can show excessive distributor shaft play.

Determining whether it is a ignition problem or fuel is your goal.

Just throwing some things out there.

I'm trying to figure this out but one thing I haven't checked is if the points insulator is good. the points are new but I may have installed something wrong?
how do I go about confirming the points insulation is good with a multimeter. I searched online but can't find a clear explanation.

not sure if I did it right, but I put one multimeter probe on the body of the distributor, and touched the other probe to the points contact.

when the points are closed I get 0.2 OHMS

when the points are open I get 14.6 OHMS

I'm not sure what that means or if I did the test right

 

[Don Frelier]

You need to disconnect the negative wire on the coil. Then repeat the one side should have infinite with points open. When closed they ground the coil.

 

[Evan Frucht]

Ok will do, wondering where to go next once I check that.

I got rid of the accel coil and went back to my stock one. I checked the coil with an ohms test. It checks out. I got 1.1 ohms between postive and negative and ~7000 ohms between postive and coil wire terminal. So I'm thinking that is goodm.

 

[Evan Frucht]

You need to disconnect the negative wire on the coil. Then repeat the one side should have infinite with points open. When closed they ground the coil.

Ok, so when I touch one probe to the contact on the arm of the points ( the one that opens/moves) and the other to distrubutor body I get "0.L" or infinity. This is with points open.

When I touch the contacts and body of distributor when the points are closed I seem to get between 0 and 1.1 ohms. Maybe I wasnt holding it steady enough but it seemed to show about 1 ohm pretty consistantly.

I'm not sure how likely the points insulator is as the cause of my problem. I'm all for ruling it out but is this kinda of a long shot?

I'm a little lost here.

These are all new points, new condenser, even a completely new distributor from rockauto with warranty.

The distributor shaft has a tiny bit side play when I really push it hard to one direction, but it feels normal to me.

 

[Don Frelier]

Your points test out correctly.
I don't think the distributor shaft should have any sideplay?
Just spinning I wouldn't expect it to wiggle if you really have to push on it.
If the points are set correctly, your problem would seem to be elsewhere.

 

[Evan Frucht]

Your points test out correctly.
I don't think the distributor shaft should have any sideplay?
Just spinning I wouldn't expect it to wiggle if you really have to push on it.
If the points are set correctly, your problem would seem to be elsewhere.

Ya the problem has been semi intermittent. For instance last time, I had it running well, was tuning, it started to sound good. Then at one point it started running bad sort of suddenly, then died. I put it to the side for a few weeks.

Now I'm trying to figure it out with a fresh eyes and a clear head.

I almost feel like the problems tend to start once the car warms up fully, but it's hard to say and I'm not sure how to confirm that. Or more important which parts which would be most likely to act up when hot. How could I check that if I'm unable to start the car for now?

Looking for ideas

I feel like it could somehow be valve related. I haven't adjusted the valves or checked.

 

[Evan Frucht]

And just to clarify when I had it running well that last time, I stopped messing with the tuning and the car was just running for a few minutes and without me making any changes it died.

 

[Curiousyellow71]

It sure sounds like your distributer is wore to me. Points can be pretty sensitive to fluctuations with movement and can cause a intermitten miss. I would strongly suggest to try a different distributer. Rebuilding also a option. We don't run points in any of our cars anymore. The pertronix kit is reasonably priced and we have had good luck with them.

 

[Evan Frucht]

It sure sounds like your distributer is wore to me. Points can be pretty sensitive to fluctuations with movement and can cause a intermitten miss. I would strongly suggest to try a different distributer. Rebuilding also a option. We don't run points in any of our cars anymore. The pertronix kit is reasonably priced and we have had good luck with them.

View attachment 1069184

Thanks,
Ima actually using pertronix igniter 3 for my VW engine build but for this car, given it's pretty stock. I was just planning to stay with points.

I have went through 2 distributors already, and this one is brand new. So it's not "worn out" but I guess it could be defective.

I'll put my dial indicator on the distributor shaft and see what side play I get.

 

[kiwigtx]

The first two things I would be looking at are the coil and the spark plugs.

Since you mentioned getting rid of that Accel coil, you're halfway there.

If the plugs are fouled up, the engine will backfire. I have had this before. I started reading this thread again, but got sidetracked part way...so if you have done so already, I suggest that you check the plugs and re-gap or replace as necessary.

Remember also that just because new plugs are new, that doesn't make them good.
I have had new Champion plugs that were toast without ever being installed.

 

[Curiousyellow71]

It seems like the pertronix doesn't seem to care much about voltage fluctuations compared to points, I think you would be happy w pertronix and if you have another issue it will help you sort it out.. I have had a pertronix that was a dud before, but that was when they first came out. Also had one that the same miss happened with points and the igniter, and the only fix was a new distributor. You have done that so I think its unlikely the new one is a dud, but points in some cars is just a struggle, the problems fluctuate as the condition of the points change.

 

[Evan Frucht]

The first two things I would be looking at are the coil and the spark plugs.

Since you mentioned getting rid of that Accel coil, you're halfway there.

If the plugs are fouled up, the engine will backfire. I have had this before. I started reading this thread again, but got sidetracked part way...so if you have done so already, I suggest that you check the plugs and re-gap or replace as necessary.

Remember also that just because new plugs are new, that doesn't make them good.
I have had new Champion plugs that were toast without ever being installed.

I did at one point recently remove all the plugs and clean and inspected them, they seemed fine too me but I didnt go that deep into testing them. They were not burned up or anything, I was running a little rich though I think due to a lower than idle idle speed I was running

 

[Curiousyellow71]

What heat range of plugs are you running? When you increase performance its not uncommon to need a colder heat range. Most autoparts store recommend way to hot of heat range. They can look ok and run like crap.

 

[Evan Frucht]

It seems like the pertronix doesn't seem to care much about voltage fluctuations compared to points, I think you would be happy w pertronix and if you have another issue it will help you sort it out.. I have had a pertronix that was a dud before, but that was when they first came out. Also had one that the same miss happened with points and the igniter, and the only fix was a new distributor. You have done that so I think its unlikely the new one is a dud, but points in some cars is just a struggle, the problems fluctuate as the condition of the points change.

What heat range of plugs are you running? When you increase performance its not uncommon to need a colder heat range. Most autoparts store recommend way to hot of heat range. They can look ok and run like crap.

I believe NGK 5 forget the exact number. But they are the nice ones I'm pretty sure.

This car ran great with these plugs and points for the longest time. I've taken it on long roadtrip and it went like a champ on a drive up to big bear which is a long winding climb up to 7200 feet.

That's the main reason I'm hesitant to ditch the points just yet. It is tempting, but I'm not quit convinced it would actually solve my problem (though I want to believe it)

I'm wondering if something abruptly happend with my valve train?

This problem started a few months ago and has been persistent yet random, and seems to get worse, but then it also will randomly sometimes run ok for 10 minutes maybe. So it's really frustrating...

My old coil seems to check out perfect with a multimeter

These are the thoughts crossing my mind right now

 

[Evan Frucht]

One other thing is that this all pretty much started with a condenser going bad:

It was driving fine for the past year befor this...

After breaking down the first time it would not start and backfired when I tried. Once I got it towed home, I replaced the condenser and it fired right up and sounded good. I got busy with other stuff, then after maybe a week passed by I tried to start it again and work on tuning and such. But something was not right, it was having trouble starting again and was running erratic.

At that point I realized my vaccum advance on the old distributor I had was not working ( but ITS VERY POSSIBLE it had been bad for the whole time I've owned the car, but just ran fine with only the mechanical advance working)... basically I'm NOW thinking it might of been the condenser, not the VA...

Anyways in a desperate effort to fix my problems I bought a brand new "Spectra Premium" distributor from rockauto.com

That new distributor seemed to fix the problem, but again... only temporarily and sort of...

I have a weird feeling some other part of my electrical/charging system or SOMETHING IS CAUSING MY CONDENSERS TO REPEATEDLY BURN OUT... Is that possible even?

 

[Curiousyellow71]

[QUOTE="Evan Frucht, post:
I have a weird feeling some other part of my electrical/charging system or SOMETHING IS CAUSING MY CONDENSERS TO REPEATEDLY BURN OUT... Is that possible even?[/QUOTE]

Yes
you just described a common thing with points, runs great, then things slowly get worse and old issues show up. You replace the points and then repeat.
Some cars will go for the longest time, others will haunt you. Unfortunately that is common. Its hard to say on the quality of the reproduced part rock auto sells as well. Is it up to the standards of someone skilled who rebuilds them on a distr machine? Not likely.