Current status of centrifugal advance distributors

[alexiskai]

Originally Posted by Jim Brierley

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.

I think you mean the advance was limited. That is one of the drawbacks to the B setup, the other being its fragile design.

It's important with either the A or B distributor to have a cam that's machined correctly. You can run the B distributor with the A-style cam if your engine doesn't rev too high.

[ModelA29]

This is a very early Mallory dual point. It used the original pop out ignition cable. It only had 1 set of points and they are impossible to find. I'm making a set using V8 flathead points and machining new phenolic block.

[duke36]

Jim in post 20 is correct; however the FSI zipper (with H.C.head) may need to be modified with different springs from FSI to get enough retard to prevent pinging (knock) on hills. Also, our zipper had no casting pin to lock the distributor to the head like a stock one.

[ModelA29]

Originally Posted by duke36

Jim in post 20 is correct; however the FSI zipper (with H.C.head) may need to be modified with different springs from FSI to get enough retard to prevent pinging (knock) on hills.

There is also a difference between early Zippers and the current ones. I need to send my early one in to have it modified for my 7:1 Brierley head. There are several internal parts that need to be changed to bring it current.

[Zax40]

There was a Mallory YA11A distributor as well. I think it was earlier than the Mallory YL11A distributor. Both could be had with single or dual points according to what I have read

[Milk Truck]

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I had FSI modify a B dist. for me so that I could time it same as an A dist. It wasn't expensive and it works well.

[bogiediver]

Quote:
*****
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).
*****

Some other Pros –
- available as 6vPos or 12vNeg
- phone support available from the company
- 30 month warranty

Worth the price to keep the original look.

Quote:
*****
FSI zipper (with H.C.head) may need to be modified with different springs from FSI to get enough retard to prevent pinging (knock) on hills.
*****

When buying direct from Shawn at FSI – he will build the distributor with the proper springs & weights for the proper advance based on what you tell him about your engine (which head, rebuilt or not, etc.).

Quote:
*****
…zipper ha[s] no casting pin to lock the distributor to the head like a stock one.
*****

True – but the side set screw can hold the distributor in place if tightened sufficiently.

Quote:
*****
[Most] Petronix/Ignitor failures were self-inflicted by improper grounding and leaving the ignition key on.
*****

A comment I've heard related to this is that “you can’t carry an extra distributor should a ‘roadside repair seminar’ become necessary”.
But, you can carry an extra ignitor plate that can be replaced with about the same degree of difficulty (don’t ask how I know…).

And, if you have a timing degree indicator mounted to the front of the engine, you can still use a Nu-Rex timing wrench to set the timing. My FSI set up was designed (by/from Shawn based on my engine configuration) for 5* advance at idle – so I locate TDC with the timing pin, verify it against the indicator scale, then move the timing mark on the pully to 5* advance on the indicator scale, then use the Nu-rex wrench per the instructions. Since I start with the engine positioned at 5* advance, when I’m done with the Nu-rex wrench procedure, the distributor is set for 5* advance.

Shawn makes himself available for assistance and diagnostics by phone, he’s very helpful.

The only issues I’ve had were both self-inflicted - not initially tightening the set screw enough (allowed the distributor to move, taking the timing out of adjustment) and inadvertently shorting the ignitor while installing an updated coil (you all know that smell of the magic smoke as it escapes an electronic device).

Have 5k+ miles on using the FSI Zipper and am very satisfied with its performance.

All of the above is IMHO & FWIW.

[CarlG]

Originally Posted by bogiediver

Have 5k+ miles on using the FSI Zipper and am very satisfied with its performance.

I got 5,000 miles out of my Zipper before it failed,

[AzBob]

Originally Posted by CarlG

I got 5,000 miles out of my Zipper before it failed,

What was cause of the failure? Inquiring minds want to know.

[bogiediver]

Originally Posted by AzBob

What was cause of the failure? Inquiring minds want to know.

Agreed...

[CarlG]

Originally Posted by AzBob

What was cause of the failure? Inquiring minds want to know.

Originally Posted by bogiediver

Agreed...

The module died. I sent the Zipper back to FSI, they fixed it by replacing the module. I also bought an extra module as a spare. In the interim I installed a rebuilt original. It worked so well that I've never got around to switching it out again. It is still sitting on my shelf should the urge appear. FSI never indicated what the cause of failure was.

[nkaminar]

Modern ignition systems vary the timing according to sensors on the engine, such as a knock sensor. The advance curve is programmed into the computer based on the rpm, throttle setting, air temperature, air flow, etc.

In 1930 the computer was under the driver's hat.

[Lawrie]

I have a unit from a jap car on my 28
It takes a lot of machining , adjusting the curve , adv limit and vac advance to get right.But has been on my A for maybe 20K miles,
Lawrie

[German guy]

I bought and installed the FSI "zipper". I drove it for about 150 miles before putting my "Henry"(Made in Berlin 1930 Tudor Delux three door) to bed for the winter. Starts were vastly improved, running at all RPMs was immensely smoother. The final test will be when I install the new 6.1:1 head when my barn gets warm enough to work without freezing my fingers. FSI claims that the "zipper" is preset for up to the 6.1:1 advance curve. We will see in March.