Severe bucking coming home

[rivcokid]

Good morning all. Well, I took the 31 roadster to the club meeting last night. All was fine until about halfway home it started to buck. By the time I got to my street, it was pretty severe. There was little power when I pressed the accelerator, but I did manage to get it home. I noticed that when it was not in gear, the engine seemed to sound ok, but once under load, the bucking started again. When it was severe, it was in 3rd gear.

About a week ago, I tried to remove the distributor but couldn't because of the ignition cable clamp. So, I replaced the points while the distributor was on the car. I have not checked them since but haven't driven much.

I noticed on older posts people mentioned points and carb. I haven't touched the carb in many months but I did smell some gas last night driving home.

Do you think it may still be either points or carb, or is this a much larger issue?

Thanks as always!

[Big hammer]

Points , check the gap and clean them , new points cam followers wear down very quickly . Maybe you didn’t tighten a screw ? ( was going to say you have a loose screw but that doesn’t sound right to post )

[Bob Bidonde]

The problem is most likely to be in the ignition. Check the simple ignition things first, as Big Hammer suggests.

[rivcokid]

Originally Posted by Big hammer

Points , check the gap and clean them , new points cam followers wear down very quickly . Maybe you didn’t tighten a screw ? ( was going to say you have a loose screw but that doesn’t sound right to post )

Perhaps it isn't right to post, but it's definitely true!!

[Will N]

Was it a hot night there in the Golden State? Could be vapor lock. Vapor lock can worsen when the level of the gas in the tank drops. A full tank can put enough pressure on the gas in the line to prevent bubbles from forming. As the tank level drops the pressure on the gas in the line gets less and less and bubbles can form.

[rivcokid]

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Whew!! It was the points. Got out there this morning and i could have put 2 or 3 feeler gauges in the gap there. Readjusted and took for a drive.

Thanks again everyone!!!

[gdmn852]

Hello, repro parts strike again, I presume?

[The Master Cylinder]

The rubbing block wearing down would close the points gap and retard the timing. I don't understand how the opened up??

[J Franklin]

Originally Posted by The Master Cylinder

The rubbing block wearing down would close the points gap and retard the timing. I don't understand how the opened up??

The movable point might not have been clamped tightly.

[The Master Cylinder]

Originally Posted by J Franklin

The movable point might not have been clamped tightly.

True, but that has nothing to do with using reproduction parts...

[rivcokid]

@gdmn852 - I don't know, but that's the likely suspect.

As for the other thoughts, I had heard that the points need to be adjusted a few times if new. Apparently (and I'm guessing here) the part that is hit can be soft and over a few miles, it can get hit enough to cause the point gap to open. Considering how wide the point gap was when I got to it this morning, that seems plausible. It was not loose - I tried to move the point screw without loosening the top screw and I couldn't - the installation seems to have been good. But for some reason, the gap opened.

[Big hammer]

I had an issue with the points gap changing, the fixed point mount was cracked letting the fixed point to move , replaced it and all was good . If it happens again check it out .

[jeepguy1948]

I think a dwell meter might be handy

[old ugly]

i assume that you have the original style points in there as you have said the adjustable contact is tight and you can not turn it with a screwdriver.
but
if you have the newer change up points plate that uses 1950-1960 style points then check that the follower has not melted.

[Benson]

Originally Posted by old ugly

i assume that you have the original style points in there as you have said the adjustable contact is tight and you can not turn it with a screwdriver.
but
if you have the newer change up points plate that uses 1950-1960 style points then check that the follower has not melted.

Recently I saw a brand new Super B plus distributor brought in because it would not run, where the plastic on the rubbing block on points melted. and deformed into puddle of molten plastic.

It was hard to tell which happened first.

1. Did rubbing block quickly wear down first and then did points electrically overheat melting plastic.

2. Or did the plastic block simply melt into a puddle of melt because of cheap plastic and then did points electrically burn and overheat.


In any case the point gap was about .005 and brand new point surface was burned. Points were of unknown source.

[old ugly]

Originally Posted by Benson

Recently I saw a brand new Super B plus distributor brought in because it would not run, where the plastic on the rubbing block on points melted. and deformed into puddle of molten plastic.

It was hard to tell which happened first.

1. Did rubbing block quickly wear down first and then did points electrically overheat melting plastic.

2. Or did the plastic block simply melt into a puddle of melt because of cheap plastic and then did points electrically burn and overheat.


In any case the point gap was about .005 and brand new point surface was burned. Points were of unknown source.

I've seen this so many times. people buy the "modern points plate", (it is not modern). most of the time it has those points with the plastic follower.
my best guess why this happens, that plastic follower is riveted to the point arms, i suspect the rivets create resistance and heat up melting the cheep plastic. only a guess.
i will never use them and i will never advise someone to buy them and i through them out if i work on car with them. it is not just model A that it happens to. i had to fix a dead 55 victoria, melted point set, the point were near new.