Pertronix differences

[Anonymous]

I have a 1966 mustang, stock 200 engine, which has a Pertronix ignitor upgrade several years back. Pertronix part number 1266. I'm going to upgrade the distributor from a 1968 so I can take advantage of this distributors mechanical advance. A tip that is recommended in the "Falcon Performance Handbook". But it appears the Pertronix part number for the 1968 is 1261. What is the difference between a 1266 and a 1261 Pertronix ignitor system? Can I use my 1266 on a newer 1968 distributor? I was on the Pertronix wesite, and it appears they are now only offering their ignitor II system. Has their original ignitor upgrade been discontinued? Second part question. Can I use the original carb with the new type mechanical advance distributor? Or should I be carb shopping? Thanks for any advice. Lowell

 

[LaGrasta]

My guess is you can use the old carb and electronic ignition.

 

[MustangSix]

The thing that makes the difference between the two pertronix systems is the shape of the cam lobe and the breaker plate.

The early distributor has a slot in the center of the shaft and a small clip that holds the rotor. The later distributor has a flat on the shaft to hold the rotor and no clip.

You can use them interchangeably if you are willing to file the screw opening to match the breaker plate. The magnets will fit either style.

 

[CZLN6]

Howdy Lowell:

On the carb- your original '66 Autolite 1100 is designed to work with the '66 Load-a-matic, vacuum advance only distributor, with its Spark Control Valve.

The '68 distributor can work with the '66 carb, but it will not work as well as a '68 Autolite 1100 or a '69 Autolite 1101. The '68 1100 does not have a spark control valve and uses regular ported vacuum source for the distributor vacuum advance. Unfortunately, it was reduced in flow capacity from 185 to 156 CFM- NOT wht you want. The '69 1101 does not have the SCV either, and it has increased CFM capacity of 215 CFM for a little more excitement.

If you do use the '66 1100 use a full manifold vacuum source for the distributor. You may need to use a spark plug one step colder, and do not exceed 10 degrees initial advance.

Adios, David

 

[XFlow_Fairlane]

huh....

I just took my pertronix I had in my 62 dizzy and put it in a 68 dizzy. did that back over my xmas break and have had no problems? was a little tight going on was all.

 

[65coupei6]

The difference is in smog equipment. The earlier year had no thermactor and the later year did. You can use either pertronix in either dizzy as MustangSix said. But, you may not even have to file anything down.

 

[Anonymous]

I just noticed David's comment that the '68 1100 did not have a spark control valve. What is the round "disc" looking item to the left of the vac nipple on the '68 1100. I thought that was the SCV? I am hoping my carb isn't the wrong one.

 

[mustang6]

What you are describing is a spark control valve, which means your carb is earlier than a 68.

 

[Anonymous]

Interesting, because I just rebuilt the carb with a '68 rebuild kit...

 

[Anonymous]

Carb rebuild kits typically cover many different year applications and model variations. It is not uncommon to have extra unused items in the kit that may have fit different configurations of the same basic carb body.
Doug

 

[Anonymous]

So how does the SCV effect my operation? I think I need more advance to eliminate the sputter found during intial acceleration.

Will removing the SCV give me more vacuum to the advance?

 

[mustang6]

Have you read the sticky messages at the top of this forum? There is one on the SCV and how it works, and one on the pre-68 load-a-matic distributor and how it works with the SCV. Basically, the pre-68 carb is not compatable with the post 67 distributor. Many people appear to get by with swapping over to manilfold vacuum, but it is not optimum as far as advance curve goes..

 

[CZLN6]

Howdy All:

Montego man- As with many things FoMoCo- changes were not always made at a specific model year. They changed to the new parts when the old were used up. Thus, you may have gotten a carb/distributor combo left over from '67. Check to make sure the Distributor is a Load-a-Matic type for compatibility with the SCV in the carb.

Under any circumstances, add more intial advance. Always use as much initial advance as your engine and settings will allow.

Removing the SCV will not get you more vacuum advance. And If you do not have a Load-a-Matic distributor, your solution will be to find a '68 1100 that has a ported vacuum source and no SCV, or go to a full vacuum source to the distributor and compensate by reducing initial advance. In addition to listening for tell-tale knock, watch your plugs for signs of glazing and/or peppering. You will hear knock when lugging, you may not hear knock at highway cruising speeds/highest vacuum, but if you have too much advance your plugs will heat glaze and/or have little pepper like speck on the porceilin- both signs of high heat/too much advance.

Adios, David

 

[Anonymous]

David,

Thanks for the help.

I am trying and struggling to rid the car of the sputter at initial acceleration.

I have narrowed, with this forum's help, the problem down to:

1) fuel accelerator pump

2) spark advance

I have rebuilt the carb and the pump is operating normally by squirting fuel as it should. It is a TOMCO core, but I rebuilt it. The SCV port is open and threaded. Right now, the SCV is in it. The car runs fine with the exception of the annoying sputter.

The distributor is a "C8," w/dual vacuum, dual advance.

I have a ported vac switch on the thermostat housing. It is brand new.
Is this what you mean by a "ported vacuum" source?

The advance vac line comes off the carb and the retard line comes off the manifold. My hoses are run per the shop manual for IMCO engines.

At idle, there is little vac on the advance and strong on the retard.

Should I just plug the SCV port? And, could the combination of the SCV with the dual advance distributor cause the stumble?

 

[CZLN6]

Howdy Back:

Q- "I have a ported vac switch on the thermostat housing. It is brand new.
Is this what you mean by a "ported vacuum" source?"

A- No. I mean a ported vacuum source higher on the body of the carb. The switch on the thermo housing is a heat switch I believe.

Q- "Should I just plug the SCV port? And, could the combination of the SCV with the dual advance distributor cause the stumble?

A- Yes, my advice would be to plug the SCV port and use full manifold vacuum to the advance side of the distributor. I would disconnect the vacuum retard of the diaphram. You may need to retard the initial as direct manifold and initial may be too much at high vacuum engine conditions.

The SCV with the dual advance could be confusing the distributor curve and causign the stumble.

There are many ways to skin a cat. Give it a try and report back.

Adios, David

 

[Anonymous]

The vacuum switch tee was used as another emission control device. It was used in conjunction with the dual vacuum advance canister on the distributor. While the engine was warming up, it sent full manifold vacuum to the retard side of the distributor canister. This retarded the spark advance resulting in higher combustion temperatures which had the effect of warming up the engine faster and burning some of the otherwise unburned hydrocarbons during the warm-up period. Once the engine coolant was warm, the vacuum switch closed off the manifold vacuum port signal at the tee, and very little or no vacuum was sent to the retard side of the vacuum canister. Simon posted a nice drawing of the vacuum tee hookup on this thread.

http://fordsix.com/forum/viewtopic.php? ... uum+switch

Doug