Current status of centrifugal advance distributors

[alexiskai]

This is a roundup of the current options for centrifugal advance distributors for the Model A.

Many people believe that operating a manual spark advance is part of the Model A experience. If you're one of these people, this post is not for you – do not read further and do not reply with your opinion.

The purpose of a centrifugal advance distributor is to automatically advance the ignition timing as the engine rpm increases. The graph of rpm to degrees of advance is called the timing curve. Most distributors use a system of spinning counterweights and springs to advance the distributor cam.

Product: Nu-Rex Automatic Advance
What it does: Installs in the valve chamber; replaces the lower shaft with a spinning weight on a spring; as the weight spins faster, it advances the rotation of the shaft above it. Provides 29° total timing at 1800 rpm.
Difficulty: Moderate
Pros: Retains original A distributor and manual spark control (if needed); high-quality timing curve; relatively cheap ($220).
Cons: Requires mild mechanical aptitude to install and can't be easily removed; timing curve unsuitable for high-compression heads over ~6:1.

Product: FSI distributor
What it does: Uses Pertronix electronic ignition instead of points & cam; vendor can supply weights and springs for most timing curve options.
Difficulty: Easy
Pros: Most flexible product in terms of timing curve options; no mechanic skill required.
Cons: On the expensive side ($380); can't use stock plug connectors; doesn't look stock; the Pertronix component has a reputation for failure among some repair shops.

Product: FSI Zipper distributor
What it does: Same as std FSI distributor but with outward appearance almost identical to stock A distributor.
Difficulty: Easy
Pros: Lets you use stock plug connectors; all the benefits of the FSI distributor with stock appearance.
Cons: Most expensive option (currently $600 with accessories).

Product: Mallory YL11A distributor
What it does: Vintage aftermarket distributor; 28° advance (I think)
Difficulty: Hard unless you can find one already restored
Pros: Excellent reputation for reliability; cores readily available.
Cons: Parts and expertise have become very difficult to find, so if you can't get your hands on one in good condition (which will probably be expensive), you might have a long road ahead of you to restore it.

Product: Model B distributor
What it does: Ford's first attempt at centrifugal advance was on the 1932 Model B. The distributor resembles the A distributor but has very different internals. Provides 14° of advance.
Difficulty: Moderate
Pros: A true "period-correct" modification; relatively cheap, lots of cores out there; easy to rebuild if you can rebuild an A distributor.
Cons: Limited advance means the user must adjust initial timing by trial and error; stock springs have a reputation for being too stiff; correct condensers very hard to find; only one supplier for shaft assemblies (Renner's Corner).

Product: B+ distributor
What it does: Modern reproduction of the B distributor using off-the-shelf parts; same 14° advance as the original B.
Difficulty: Easy
Pros: No mechanical skill required; good vendor support (Means Garage); cheaper than FSI ($300).
Cons: Short track record for reliability; limited advance means the user must adjust initial timing by trial and error; doesn't look stock; can't use stock plug connectors.

Product: Roll your own distributor
What it does: Take a "classic car" distributor such as the Lucas 25D or a modern one from 123Ignitions and modify the casting and shaft yourself to fit the A engine.
Difficulty: Hard
Pros: Best performance and flexibility; potential to add vacuum advance.
Cons: Requires significant machine shop skill and equipment; doesn't look stock, can't use stock plug connectors.

Did I forget any?

[alexiskai]

Originally Posted by alexiskai

Product: Model B distributor
Cons: stock springs have a reputation for being too stiff

I have been working on developing alternative springs for the B distributor. This is an ongoing project, but if anyone is interested in experimenting with their existing B distributor I can point you to the off-the-shelf springs that I've had the best results with so far. PM for info.

[CarlG]

I recently read somewhere that there was a guy in Missouri making a distributor for the Model A that had centrifugal advance and used common parts available at NAPA or O'Reilly, but I lost the information. Anyone heard of them?

[alexiskai]

Originally Posted by CarlG

I recently read somewhere that there was a guy in Missouri making a distributor for the Model A that had centrifugal advance and used common parts available at NAPA or O'Reilly, but I lost the information. Anyone heard of them?

That's the B+ distributor in the list, made by Means Garage.

[J Franklin]

If you are curious about the NuRex unit, I have a new one for sale $120. PP in the US.

[Hitman]

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Kong distributors.

You might as well discuss the stock A distributor for comparison sake, you have the B and others. Stock A distributors are the baseline.

Also missing:
-electronic pick up or mechanical points
-advance type, mechanical, vacuum or hybrid.
-total advance
-advance curve
-specific coil required

[alexiskai]

Originally Posted by Hitman

Kong distributors.

You might as well discuss the stock A distributor for comparison sake, you have the B and others. Stock A distributors are the baseline.

Also missing:
-electronic pick up or mechanical points
-advance type, mechanical, vacuum or hybrid.
-total advance
-advance curve
-specific coil required

- All listed distributors use mechanical points except the FSI units.
- This is a list of centrifugal advance distributors, so I did not include the stock A distributor or the advance type. None of the units listed include vacuum advance.
- All units with a fixed total advance have their total advance specified. The FSI units have a variety of possible advances so I didn't list them.
- The advance curve for most of these is unknown (to me, anyway).
- No specific coil is required. FSI recommends the Pertronix coil but that coil is nothing special.

Kong distributors were omitted. They are quite rare and I never see them discussed. Feel free to add an entry for them yourself.

[Charlie Stephens]

Your comment about Model B condensers being hard to find it true but a Model A condenser is easy to modify for use on the Model B. Just be sure to start with the best one available (Brattons?).

Carlie Stephens

[alexiskai]

Originally Posted by Charlie Stephens

Your comment about Model B condensers being hard to find it true but a Model A condenser is easy to modify for use on the Model B. Just be sure to start with the best one available (Brattons?).

Carlie Stephens

Good addition and thanks for the pictures. I bet you could put a couple of bends in the tab to make it fit even better.

[Wick]

What about the modern Mallory, I have one new in the box.
Wasn't the vw and I think a nissan distributor also converted to work on the A ?

[alexiskai]

Originally Posted by Wick

What about the modern Mallory, I have one new in the box.
Wasn't the vw and I think a nissan distributor also converted to work on the A ?

I haven’t heard much about modern Mallorys. Do they work right out of the box? Feel free to add an entry for them with pros and cons.

I’ve heard of VW and Honda distributors being adapted for the A. That goes under “roll your own” distributors. They all need to be machined to work on the A and no one has published a guide to modifying one.

[Zax40]

Originally Posted by Wick

What about the modern Mallory, I have one new in the box.
Wasn't the vw and I think a nissan distributor also converted to work on the A ?

Is that the one with part number Mallory 2301105?

[emf]

Originally Posted by Wick

What about the modern Mallory, I have one new in the box.
Wasn't the vw and I think a nissan distributor also converted to work on the A ?

Isn't the new Mallory a 12 volt only option? I had one that was almost new, but it required a 12 volt source. If you can find and original Mallory with mechanical advance only, they are superior (my opinion). One drawback is the lack of parts. Occasionally you find them on ebay, but they are dear...


Frank

[denis4x4]

Follow up on the Per-Lux Ignitors/Petronix: This distributor was originally designed for stationary engines running 24/7 and fork lifts. First automotive use was for VW Baja racers. Micky Remund, engine builder for Micky Thompson, cut a deal with Per-Lux to create a line of products for early Fords. Micky sold his operation to FSI. I have one of Micky's original distributors and worked with Mel at FSI to get a number of springs to play with the advance. Almost 100% of the Petronix/Ignitor failures were self inflicted by improper grounding and leaving the ignition key on. I've installed Petronix/Ignitors on every old car I've owned plus a couple of classic boats. The only failure was self inflicted when I failed to properly ground the unit.

[alexiskai]

Originally Posted by denis4x4

Almost 100% of the Petronix/Ignitor failures were self inflicted by improper grounding and leaving the ignition key on.

Good to know!

[Joe K]

I can verify the B stock distributor is not "optimal."

My use is a Model B engine converted to the Gordon-Smith air compressor. A centrifugal is required because the engine/compressor has two operating states: "Idling" and waiting to pump air, and "Running" at nearly full throttle. A distributor has to cover both states in this case.

Rebuilding the B distributor, I found by using a variable speed drill to power the distributor that it "hangs up," apparently on the ramp of the "cam" within. Grease in this area helped - until the grease was thrown off at high speed.

A replacement "core" from Renners was better, but I have seen it hang up.

I still haven't found a resolution I'm satisfied with - so I'll be watching this thread as it develops.

Joe K

[alexiskai]

Originally Posted by Joe K

I found by using a variable speed drill to power the distributor that it "hangs up," apparently on the ramp of the "cam" within. Grease in this area helped - until the grease was thrown off at high speed.

Can you be more specific? There isn’t a second cam. Are you saying the weights get stuck on the little rails they slide on?

The unit I’ve been using for testing has been quite consistent, even up to 1500 distributor rpm. The grease is actually assembly grease.

[Joe K]

Originally Posted by alexiskai

Can you be more specific? There isn’t a second cam. Are you saying the weights get stuck on the little rails they slide on?

The unit I’ve been using for testing has been quite consistent, even up to 1500 distributor rpm. The grease is actually assembly grease.

You describe it better than I did. Yes, little rails which form a sort of "circular cam." The hang-up on the Renner replacement I put to "manufacturing burr" (i.e. new and "sharp edge")

Some use and some wear (not a lot) will probably solve this.

I've considered one of the "miracle lubricants" instead of common water pump grease for this. But the object now is to "wear it in" which might be delayed by higher tech slip.

Joe K

[katy]

This old thread has information about using a Honda Civic distributor, post 14
https://www.fordbarn.com/forum/showt...ivic&showall=1

[Jim Brierley]

I'm currently using a FSI on my speedster with my BRIERLEY head. It requires less advance than other performance heads. FSI is a delight to work with, tell them you are running one of my heads and they will set their dist. to match what I want, max of 10 degrees in the dist., 20 at the crank. The one thing about the FSI is that you should run power to them thru a separate, independent switch from the batt, and a direct ground wire to the batt.
I have run Mallory/Datsun dual point distributors in my OHV engines with great success, they require a slight amount of machining to fit in the head and a new shaft, both easy to do.
I ran a B dist. years ago, and it ran well but on a dist. machine the cam showed wear, so it didn't fire at 90 degree intervals, and on the one I had, the advance was unlimited, no problem on a flathead because they don't rev very high.