[sjanbob]

Hi, I have used the search function but I couldn't find the right answer.
The engine is holding in (and "four stroking") when I keep the same speed (at 50 mph for example).
Deceleration and acceleration is no problem
The breaking points are very old and I had to sanding them up because the engine was running very bad at any moment before this issue.
I have already clean up the carb, so I want to replace the breaking points for to exclude this of the problem.
All other parts of the ignition have been replaced already.
I see vented and non-vented breaking points. Which I should use or are better and what is the difference?
The brands Airtex/Wells, Standard Motor Products and ACDelco are more or less from the same quality?
The engine is a 1971 Pontiac 400 2bbl

[Sun Tuned]

I was told years ago that the unvented was used on the cars that spent lots of time idling around in traffic, and the vented were used on cars that spent the majority of time on the freeway.... fwiw.

If the brand sets you listed I'd not use any.

Get a set of echlin points from napa the upper quality set that they sell.
I wouldn't worry about vented or non vented as I personally have seen 0 difference in the two.

[mgarblik]

This is an age old argument that was never answered by 2 "experts" the same way. My answer which is the correct one in the modern world, is to get rid of the points and do a conversion if you want a stock look, or a replacement with one of dozens of better electronic choices out there. But I understand the desire to remain 100% stock, especially in the street section. So here are the arguments.: Some experts say the vented point contacts run cooler, thus the vent and tend to not pit and change effective dwell due to pitting and mounding of the contact surface. Other experts feel the vented points do not provide as effective and reliable switch as the solid pad contact point, especially as they wear. They say the contact area is smaller to begin with and as the points burn, the edges of the vent hole pit away, taking more and more of the contact area away until the engine quits running. Remember these expert opinions are from long ago, when these points cars were driven 10,000-12,000 miles a year. That's many years of use on most collector cars. In summary, I agree with the above post. Buy NAPA ECHLIN HEAVY DUTY POINTS. Not the cheap crap from NAPA. Or ACCEL used to sell a quality set of points. Install and go. I would strongly consider Petronix conversion if you put lots of miles on the car each year. Good luck

[steve25]

Switching a DC voltage , unlike a AC voltage even at the low current rates that coils run at makes for pitting which just compounds the local heat at the contact point!
If your wall light switches in your home had to switch DC and not AC they would not last the average 20 years, they would last maybe 3 years before intermitants drove you nuts!

Vented points do run cooler , but there smaller surface area limits how long they will last, at best I say it's crap shoot!
Some unvented points have much bigger arms there are welded to and that greatly helps in heat sinking the contacts, but with vented points your still left with having more current flowing thru less area which to me = less life.
It's the same thing as running current level thru a 18 gauge wire that call for a 16 gauge.

The one thing in all of this that is for sure is once points get pitted, or even worse yet you file them the dwell you read on a meter is not really what the motor see's if you ask me!

I have never had a set of points that I have filed up that allow a motor to idle as good as a new set of points that's for sure, no matter how careful I filed them!

[unruhjonny]

these last two posts are great!

I am a stick in the mud, as in I am running points, because that's correct.
I have had no side of the road let downs from points - the same cannot be said of my experience with HEI ~ which is essentially what one is doing when converting to electronic ignition.

[steve25]

You make a great point that I failed to make, that being that in all the many years I was running points I have never been been broken down off the side of the road!
The motor may have been running very poorly , but I always made it home, or to somewhere to get new points and stuff them in in all of 5 minutes, as opposed to having to get towed 3 times with electronic / semiconductor failure from modern systems.

[steve25]

You make a great point that I failed to make, that being that in all the many years I was running points I have never been been broken down off the side of the road!
The motor may have been running very poorly , but I always made it home, or to somewhere to get new points and stuff them in in all of 5 minutes, as opposed to having to get towed 3 times with electronic / semiconductor failure from modern systems.

[TedRamAirII]

One thing to do is examine the surfaces of the points. If they are just worn out, replace only the points. If they are very pitted, replace the condenser also. I still have ACDelco points still in the foil boxes, they are the BEST. D106P

[unruhjonny]

Originally Posted by TedRamAirII

... I still have ACDelco points still in the foil boxes, they are the BEST. D106P

What's the difference between D106P & D106PS points sets?

[unruhjonny]

Originally Posted by steve25

You make a great point that I failed to make, that being that in all the many years I was running points I have never been been broken down off the side of the road!
The motor may have been running very poorly , but I always made it home, or to somewhere to get new points and stuff them in in all of 5 minutes, as opposed to having to get towed 3 times with electronic / semiconductor failure from modern systems.

Steve, I know you (accidentally) posted this twice, but it bears repeating - and I sincerely appreciate you acknowledging my point... punn intended.

[TedRamAirII]

I maybe wrong. But I "THINK" the P had it where the coil and condenser wires clipped onto the point set and the PS has a screw to secure them.

I use a Pertronix set, but I carry a point distributor . Problem is I have taken out the resistor wire , so I carry a resistor to go inline to the coil.

[sjanbob]

Thanks all for the reactions which are very usefull.
At the moment I will not do a conversion to HEI because it's not my daily car and I don't drive so much each year. The Catalina is just for cruising around so the engine don't needs to make many engine speed for to race. So in my situation I understand that I will need unvented because it's more reliable?
I never noticed that the breaking points would be running hot.
It's neccesary that I have to order the breaking points on Rockauto for the shipping costs because I am from The Netherlands. And the NAPA website is here blocked .
Even is AcDelco orginal, I believe the STANDARD MOTOR PRODUCTS DR3575CT is a good choose (I need also to combine with other parts for the shipping costs)

[unruhjonny]

oh?

This is good stuff for me to know, because I am a little late to this game;
But hearing of a superior type/brand/pt# of points, has me looking into this...

I am trying to cross reference GM part numbers;
According to my MPC all 1970 V8 Firebirds:
#1931988 = 350-2bbl
#1966294 = all others

From some further sleuthing, it appears as though;
#1931988 = D106P
#1966294 = D112P

From more searching, I believe I found this tidbit;
#1966294 = vented points

So that tells me that the D106P is the non-vented points.

(some of the following is for future reference)

#1931988/12338659 = D106P (non-vented?; later part appears to be vented; spring clip terminal; OEM for L30)
#1966294 = D112P (long since discontinued; OEM for L78 / L74 / L67)
-----------------------
#1996289 = D106PS (screw clip terminal vs D106P spring clip)
#1876600 = D1007 (points & condenser; "uniset")
#1852134 = D1003 (D112P + condensor set)

This link was a goldmine!
https://www.google.ca/url?sa=t&rct=j...u1YKT9HOlBgqKA

[unruhjonny]

Originally Posted by sjanbob

Thanks all for the reactions which are very usefull.
At the moment I will not do a conversion to HEI because it's not my daily car and I don't drive so much each year. The Catalina is just for cruising around so the engine don't needs to make many engine speed for to race. So in my situation I understand that I will need unvented because it's more reliable?
I never noticed that the breaking points would be running hot.
It's neccesary that I have to order the breaking points on Rockauto for the shipping costs because I am from The Netherlands. And the NAPA website is here blocked .
Even is AcDelco orginal, I believe the STANDARD MOTOR PRODUCTS DR3575CT is a good choose (I need also to combine with other parts for the shipping costs)

from the pdf article i linked, the D106P/D106PS is inferred as the NAPA CS86;
If you look for that part number as a means of cross referencing points sets, you should be good to go.

[TedRamAirII]

I was told years ago, by a old GM parts guy .......maybe true? maybe not, that the ACDelco points were silver plated contacts.

[Sun Tuned]

Delco points should since 1997 were subcontracted out and manufactured by Wells.

Even the guys at plant 20 in Indiana said the points they sell made by wells were garbage.

Try a set of Napa CS89.

The better quality stuff and most all OEM Ford stuff was tungsten.

[Schurkey]

Originally Posted by TedRamAirII

I was told years ago, by a old GM parts guy .......maybe true? maybe not, that the ACDelco points were silver plated contacts.

As far as I know, quality points (or perhaps any points) had a tungsten plating. As with TIG welding, the tungsten could withstand the heat of electric arcing that silver/steel/copper etc. could not. Or, are we both right--were they silver-plated tungsten? Silver has a nice characteristic: Silver oxide is just about as conductive as shiny silver, while oxidized copper is not as good a conductor as "shiny" copper, and oxidized iron is even worse than "shiny" iron.

The ancient Delco literature made specific mention that points should not be filed, nor should you remove the "cone" of transferred point material. Filing destroys the tungsten plating; and the "cone" of transferred material represents additional surface area that is lost when the cone is knocked-off. Losing surface area could result in poor electrical flow through the points.

When point material transfers from one point to the other, reading point GAP becomes inaccurate. Point DWELL, however, is a reliable guide.

The "size" of the "condenser" (by which I mean the electrical value of that specialized capacitor) will determine which way point material will transfer. I have since forgotten which way the material transfers when the capacitor is too "small", but it transfers the other way when the capacitor is too "large". Capacitors (condensers) are nominally all rated the same, but production variances being what they were (are?) sometimes the point material would transfer from movable point to stationary point, sometimes from stationary point to movable point, and if the capacitor was "exactly right" the points just plain lasted longer.

The old distributor machines had a feature where they were essentially a continuity meter, connected through the points; "good" points had low resistance/high conductivity, while "bad" points had high resistance/low conductivity.






All of this is a good trip down memory lane. I have not actually touched a set of contact points (breaker points) in more than three decades. Until the Communists hit us with an EMP blast, I will take a transistor/breakerless ignition, thanks very much.

[steve25]

Sorry about the double post, but something was wrong with the site for few minutes and it would not take my post .
I am accually surprised it did not put up 5 or more of my post with as many times as I hit the button!

[Blued and Painted]

Ignition points. How quaint.

[Tom Vaught]

Originally Posted by unruhjonny

these last two posts are great!

I am a stick in the mud, as in I am running points, because that's correct.
I have had no side of the road let downs from points - the same cannot be said of my experience with HEI ~ which is essentially what one is doing when converting to electronic ignition.

Factory HEI Module in my 1978 Trans Am failed several times.
Used to carry a spare Module and a tube of the proper heat sink dope the factory recommended. Never could count on the car to not fail at some point.
Only two things I hated about the car: Ignition system and the fact you were basically laying on your back vs being in a "Airplane Command Position" like my wife's 1979 Mustang had. Tough going from Michigan to Florida in that TA or to Denver.

So I stayed with Points or a Magnetic trigger wheel and a MSD "Potted Case" Ignition system. As far as "Good Points" have to agree with if the point gap is set correctly and the
lube is added to the wiper for the cam/cam follower you should be good to go with a points set.

Tom V.
Never a problem in 25+ years of driving after that install.