Autom. advance spark timing

[Werner]

Guten Abend.

Is there a difference between Bratton's mechanical centrifugal ignition ($225) and Don Snyder's ($203)?
Does the device work very well?
What disadvantages are possible?

Many thanks in advance!

[29spcoupe]

They are one in the same.

[Y-Blockhead]

Originally Posted by Werner

Guten Abend.

Is there a difference between Bratton's mechanical centrifugal ignition ($225) and Don Snyder's ($203)?
Does the device work very well?
What disadvantages are possible?

Many thanks in advance!

They are the same made by Nu-Rex and are a copy of the original Phillips.

https://www.fordgarage.com/pages/phillipsspark.htm
https://www.fordgarage.com/pages/nurexadvance.htm

IMO it works very well. One "disadvantage" is in some situations your timing may be too advanced. In this situation I simply retard the advance lever some.

I set my timing so "0" advance is ~ ½ way down so I can retard the timing if needed (say on a hill)l. My timing with the Nu-Rex is set with the advance all in at 30°.

[nkaminar]

Blockhead, Thanks for the links. This is a pretty ingenious device. I learned something today. I am going to stick to my hand adjustment just because I am a control freak.

[CT Jack]

The Bratton & Snyder centrifugal advance units are the same except for the price. I have used this distributor advance unit and it worked well. Changes in engine speed causes a gimbled disk attached to the distributor drive shaft to change its angular orientation. As the the angle of the rotating disk changes it mechanically rotates the distributor point mounting plate.
I replaced this unit with an FS Zipper distributor which has a Model B type centrifugal advance along with a Petronix electronic ignition module. This system makes driving a Model A a joy. The advance retard control lever on the steering column is locked so when you go up a hill you just use the gas pedal.

[Werner]

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Good morning,


yes, this is a mechanically simple and beautiful system!



I was thinking of an invisible electronic advance ignition, but that doesn't work with my original pop-off switch, which I'm very proud of.



The most practical solution seems to be that the distributor from the B Model can be easily inserted into the A motor?



Therefore I will try to find a good used B distributor.

[alexiskai]

Originally Posted by Werner

I was thinking of an invisible electronic advance ignition, but that doesn't work with my original pop-off switch, which I'm very proud of.

The most practical solution seems to be that the distributor from the B Model can be easily inserted into the A motor?

Therefore I will try to find a good used B distributor.

The B distributor doesn't accept the original wire that runs from the pop-out switch to the lower plate. On the B, a wire comes down from the ignition and terminates at a simple screw. If you want to keep your pop-out switch and cable in original condition, but also have automatic centrifugal advance, the Nu-Rex is your only option.

[Werner]

Alexis,

thank you very well, that's important to know.
The pop off switch must remain installed. The cable change to an other doesn't matter.

But I do not know how. I have an electrical schematic for my A, but can't find one to compare for the B ignition.


Any idea how to change the wires?

[alexiskai]

Originally Posted by Werner

Alexis,

thank you very well, that's important to know.
The pop off switch must remain installed. The cable change to an other doesn't matter.

But I do not know how. I have an electrical schematic for my A, but can't find one to compare for the B ignition.


Any idea how to change the wires?

The schematic is the same. You remove the cable armor and the threaded terminal at the distributor end of the wire. Then splice on more wire if you need it, plus a flag terminal at the end. For comparison, here is the stock Model B ignition wire, which is wrapped in a loom together with the high-voltage wire from the coil.

[Werner]

Thanks, Colin, for your guiding help.

Changing the wiring is therefore not a problem. Good.

But after reading further here, another question arises:

The automatic "B" distributor has only an adjustment range of approximately 20° advance. Therefore the "B" engine is then always started with about 15° of ignition advance.



With model "A" I can use the hand lever to set the ignition point back to <0 degrees for start.

But the "B" distributor does not have this option. But then my "A" engine starts with a lot of advance. This can be bad for the hand crank and starter.

Or is it possible to convert the "B" distributor also to a manual adjustment?

[ursus]

I haven't seen it done, but it might be possible to convert it to manual adjustment albeit within a limited range. The upper plate where the points and wire from the coil attach has a tab with setscrew that is marked with gradations allowing for a range of +/- 10 degrees of adjustment from the initial 19 degrees of advancement. This would require some unique fabrication to achieve this modification.

The 15 degrees of initial advance that you cited was an error in the Ford company documents. It is actually 19 degrees.

[Werner]

Guten Abend Ursus.

Danke, that would be a nice option. I could purchase the B distributor shown below. There are probably a lot of A drivers here who have already done that like this, I hope.

Please write it now.

[alexiskai]

I have both the Nu-Rex timing device (installed, running) and a B distributor (for the project car). The B distributor is best used for high-compression heads ≥6:1, where the compression puts a reduced maximum on the total timing.

The centrifugal advance on the B distributor permits only 15° mechanical advance (in addition to whatever your initial timing setting is). So you could use it on a 7:1 head with initial timing of 7° and total timing of 22° and it would be fine. If you have a stock 4.2:1 head, you need all the advance you can get. I think a B distributor in that scenario would be a mistake.

Regarding the fitting of a B distributor plate with a ball mount for manual spark advance... seems like a bad idea. The B plate wasn't designed to be moved back and forth multiple times a day. You might bend the mount point or the tabs that support the plate in the body.

[Werner]

Originally Posted by alexiskai

... Regarding the fitting of a B distributor plate with a ball mount for manual spark advance... seems like a bad idea. The B plate wasn't designed to be moved back and forth multiple times a day. You might bend the mount point or the tabs that support the plate in the body.

OK, that's helpful advices. Who teach me that the simple NuRex centrifugal ignition is the best conversion for automated advance ignition.

They hurt, the high additional costs. The freight alone has exploded to almost 100.00 plus 7% EU customs and 19% VAT. Ouch!

But every true love has always been particularly expensive...

I would like to thank everyone again for the many patient explanations!

[alexiskai]

Originally Posted by Werner

They hurt, the high additional costs. The freight alone has exploded to almost 100.00 plus 7% EU customs and 19% VAT. Ouch!

Use Nu-Rex's contact form and just ask whether they have any tips on purchasing one of the timing devices in Germany. You never know what they might say. When I told them I was making a video about the device, they loaned me one to demonstrate with, free of charge. Very nice people.

[Synchro909]

Originally Posted by Werner

They hurt, the high additional costs. The freight alone has exploded to almost 100.00 plus 7% EU customs and 19% VAT. Ouch!

Werner,
At least you can get stuff from the US. We can't. USPS doesn't send mail to this part of the world any more - not even the MAFCA magazine. I don't even look at the "For Sale" section of the swap meeting part of this forum because I wouldn't be able to get anything I might buy.
If you'd asked me a year ago whether I would be affected by that, I'd have said "No." but I and everybody else here and many in the US are. I have a friend who married an American lady and for her, the exchange of gifts is no longer possible. That is just one tiny affect of this.
BTW, I wouldn't use a B distributor. I strongly suspect the reason B blocks are so prone to cracking is not solely due to their thinner castings but also because the distributor doesn't work properly and they run retarded, causing them to over heat, then crack. I have 3 of them and while they all look good and bushes and shafts etc are good, they don't advance properly. IMO, the best place for a B distributor is in the trash.

[jack backer]

My findings with the B distributor are the same as Synchro909,They dont 'map' (timing curve as viewed with a timing light) well and are erratic. The nurex gyro advance is adequate for a stock engine which is tolerant of timing deviation.If you decide to raise compression be advised the engines tolerance for improper timing decreases,and a precise advance curve is desired,like the FSI distributor.

[Werner]

Thank you all for this additional informations!


Colin his hint came too late, at the time of reading Snyder's had already shipped the centrifugal ignition adjuster.

In the meantime, I have also come to the realization that the B distributor is only half the story and requires a lot of attention and keen ears while driving.

I'll install the technology next week and report back.


Special question to Synchro: Why is it a problem for you to get spare parts etc. from the USA?
.

[alexiskai]

I'm still going to try to use my B distributor, but I also have a digital timing light and tachometer, so I can verify and adjust my timing curve down to single degrees. If you don't have that gear, I wouldn't try it.

[eagle]

IMO there are people who can't hear their engine, auto advance is fine for them, although I'm not sure I'd trust some of the gizmos I've seen mucked up to an A engine. If you can hear the engine, setting the timing lever is second nature after a bit. I don't even think about it when driving, that's automatic enough for me. Heard about someone who had an electric servo motor running the advance, and a tach sensor on the front pulley, all hooked up to a laptop computer that he kept on his seat, talk about a kluge.

[Synchro909]

Originally Posted by Werner

Special question to Synchro: Why is it a problem for you to get spare parts etc. from the USA?
.

Werner, The trouble is, the United States Postal Service is not sending mail to this part of the world any more. I cannot attest to the accuracy of information I received a while ago but they say it is because President Trump defunded the post office so aggressively. Where that is the reason or not, I can't say. I (and every one in the SW Pacific region) just know we can't get anything by post.
I'm waiting for some enterprising person in say, Canada to start forwarding mail from the US.

[emf]

I was told by Nu-Rex that their auto advance would not work with a Model B distributor. With my B engine set up the way it is, the B distributor would not provide enough advance at higher rpms. I finally went 'all in' and put a Mallory unit and never looked back. The only problem is that it destroys the original look of the engine compartment.


Frank

[Y-Blockhead]

Originally Posted by emf

I was told by Nu-Rex that their auto advance would not work with a Model B distributor. With my B engine set up the way it is, the B distributor would not provide enough advance at higher rpms. I finally went 'all in' and put a Mallory unit and never looked back. The only problem is that it destroys the original look of the engine compartment.


Frank

And a B engine with two 97's doesn't?? I like your air filters.

[Werner]

Today I mounted the NuRex centrifugal phaser. The stroboscope/flashlight ignition lamp indicates 0 degrees when idling and 28 degrees at high RPM. That's how it should be.

However, the engine "rings/knocks" very clearly when going uphill; I have to reduce the ignition timing at about 5 - 6 °.
Is that normal?

(The cylinder head is planed off by 0.08".)

[alexiskai]

How were you handling your spark advance before, when you did it manually?

[Werner]

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Guten Morgen,

with the hand lever the ignition was at -3° and with the lever almost down (gap 1/7") at 25°.

It is noticeable that with the automatic ignition advance full throttle uphill the engine pings more at 45 mph than at 35. If I go back 5 or 6 degrees, the knocking stops, but then there is a lack of traction.

[Synchro909]

Originally Posted by Werner

Guten Morgen,

with the hand lever the ignition was at -3° and with the lever almost down (gap 1/7") at 25°.

It is noticeable that with the automatic ignition advance full throttle uphill the engine pings more at 45 mph than at 35. If I go back 5 or 6 degrees, the knocking stops, but then there is a lack of traction.

Werner, the last thing you need is pinging. That means the timing is very much too advanced and it does great damage to the bottom end of the motor. I wonder whether you are expecting too much from the engine. How is it unmodified? It clearly is running higher compression if you can get it to ping at 25° advance. That's about the maximum advance for a 5.5:1 head. On one of my engines, I run a 6:1 and gave up on a Model B distributor very quickly. Instead, I run a standard A distributor and with the aid of a timing scale on the front of the motor and a timing light, I made a fitting I screwed to the side of the distributor. It has a screw in it that works like a throttle stop on the carburettor to limit the movement of the top plate. I set it to 22° so no matter what I do with the steering column lever, it cannot go past 22°. It works very well but I can get a ping at low speed if I press the accelerator too far.
When you hear pinging, push the lever up till it stops. That is as much as you can do on those hills.

[nkaminar]

My computer adjusts the timing for different conditions such as cruising down the highway or going up a hill or idling. My computer resides under my hat.

[jack backer]

Stock compression engines are tolerant of timing deviation, manual spark is effective.Higher compression engines require mechanical spark control to avoid detonation.

[old31]

What am I missing here, other than brain cells.

Yes, the device is clever. The ONLY advantage i can see is for those that can not hear the engine.

It has a cost associated with it that is not needed.

It takes mechanical knowledge to install.

You have introduced 1 more item that has the chance to break or not work and cause damage.

I don't think it does a better job at regulating the timing, as long as you can hear the engine.

So, unless someone can show me the advantage I am 100% with NK.

[jack backer]

Timing for a model a engine for optimal performance is roughly 1 degree advance per each 100 rpm.. for instance 10 degrees advance at 1000 rpm… both accelerating and decelerating. That being said,at 4.2 to 1 compression the engine will perform adequately adjusting it manually,if that is your preference.

[alexiskai]

I would be interested to see what happens if you drain the gas, put a couple gallons of high-octane petrol in it, and run those hills again. In Germany, you should be able to get 95, 98, or 100 octane. Try it and see if it makes any difference. This will help diagnose the issue.

[SonicRaT]

Originally Posted by alexiskai

I would be interested to see what happens if you drain the gas, put a couple gallons of high-octane petrol in it, and run those hills again. In Germany, you should be able to get 95, 98, or 100 octane. Try it and see if it makes any difference. This will help diagnose the issue.

I have the device installed in my '31 coupe with a 6:1 head and run 93 (US rated) almost exclusively. I was a bit concerned that I would need to add some additional adjustability through the lever when I set it all up, as most warned against the combination. However, I've not experienced any knocking or issues leaving my lever set at TDC. I've run it quite aggressively through a variety of driving conditions without a hitch so far. I haven't yet tried a lower octane, as most of the time it is mixed with ethanol here, but I've been curious if I would pick up a ping if I did.

[bavArian]

Standard petrol engines on cars today have a 9:1 compression or higher. I don't see how a 6:1 head could induce problems, even with the higher mixture temperature compared to direct injection.


Over here you can only get 95 octane or higher fuel, so I doubt it's a fuel problem.

[jack backer]

This is true but you are not comparing it correctly, Modern small piston OHV engines at 9 to 1 compression ratio has a different ( and way shorter) flame travel and the opportunity for detonation is way lower than an L head at 6 to 1 with 50 cuin pistons. On a modified A engine combustion chamber design can help create a detonation condition.

[TomInCologne]

Originally Posted by jack backer

This is true but you are not comparing it correctly, Modern small piston OHV engines at 9 to 1 compression ratio has a different ( and way shorter) flame travel and the opportunity for detonation is way lower than an L head at 6 to 1 with 50 cuin pistons. On a modified A engine combustion chamber design can help create a detonation condition.

as a combustion engineer... this is true,but don't forget that at the higher pressure the flame speed will be a lot higher than at the lower pressure...


Sorry, i was just trying to confuse matters more... ;-)

[alexiskai]

A lot of stuff can cause detonation at "normal" advance numbers, not only compression. For example, the plugs might be too hot, or there might be too much carbon build-up. Another possibility is that the owner makes a mistake with initial timing, so the actual total timing is higher than he thinks. I asked about octane because it's a test that would yield some information without requiring engine surgery.

[Werner]

Hi,


I always drive high-octane alcohol-free gasoline. I fill up with leaded fuel every now and then. (This makes the engine run much smoother.)

Modern iridium spark plugs, whose heat value I have now increased from 5 to 6 (NGK) for the test drive. No difference.

If I richen the mixture 1/8 on the choke spindle, the knocking is a little less.

The combustion chamber and the piston head are very clean, so I can rule out glow ignitions caused by carbon.

It is not engine knocking at low speeds and high loads, but the typical "high speed knocking".

Perhaps the NuRex's automatic advance is too fast. I will try to record the ignition timing with the strobe and camera while driving at the beginning of the engine pinging.

[jack backer]

Originally Posted by TomInCologne

as a combustion engineer... this is true,but don't forget that at the higher pressure the flame speed will be a lot higher than at the lower pressure...


Sorry, i was just trying to confuse matters more... ;-)

I had the opportunity to tune a Miller OHV conversion on a Model A what I found interesting is how much advance it would “take”. We didn’t map it but I would estimate it at 30 to 40 degrees..


Werner the gyro type advance curve is fixed, unlike a flyweight advance where you can adjust curve by altering spring tension. I would set base idle timing at 0 degrees as a starting point to “pull” the curve back to avoid detonation.

[Ruth]

This has been discussed in previous threads where it is suggested to set your 0° ½ way down the quadrant so you can retard the timing if needed. The Phillips/Nurex will advance the timing 30° and I have found instances where my engine doesn't want that much.

[alexiskai]

Yeah, setting the Nu-Rex's baseline to somewhere ATDC is a decent workaround and won't hurt the car (unless you idle for a really long time). It's just odd to me that a stock engine wouldn't take 28° advance, particularly if you're using high-octane petrol. Something else must be going on, although we may never know what.

[SonicRaT]

Originally Posted by alexiskai

A lot of stuff can cause detonation at "normal" advance numbers, not only compression. For example, the plugs might be too hot, or there might be too much carbon build-up. Another possibility is that the owner makes a mistake with initial timing, so the actual total timing is higher than he thinks. I asked about octane because it's a test that would yield some information without requiring engine surgery.

Originally Posted by alexiskai

Yeah, setting the Nu-Rex's baseline to somewhere ATDC is a decent workaround and won't hurt the car (unless you idle for a really long time). It's just odd to me that a stock engine wouldn't take 28° advance, particularly if you're using high-octane petrol. Something else must be going on, although we may never know what.

That's exactly right. I had picked up a few different sets of plugs when I installed the unit along with the 6:1 head, as I was expecting the possibility of some trouble. I also have my ignition system quite well sorted, so all proper gaps, new points, condenser, and plate wiring. It had Champion C-16C in it when I acquired it, and I've left those in for now and they've run quite well. I have the NuRex locked in at TDC and no pinging, on either the stock cam or a 340 grind. It is definitely possible to run it that way on pump fuel.


ETA: I love your YT vids too!

[jack backer]

FSI recommends idle timing at 0 degrees as well. Combustion chamber turbulence has an effect on timing as well, the Flathead chamber has been studied for decades, Briggs and Stratton has a great design, Jim Brierleys Silberstein design incorporates a stepped chamber that effective too. I run an original Winfield 7 to 1 and an NOS late B high lift cam and still need to control timing to avoid detonation.

[alexiskai]

Originally Posted by SonicRaT

I have the NuRex locked in at TDC and no pinging, on either the stock cam or a 340 grind. It is definitely possible to run it that way on pump fuel.


ETA: I love your YT vids too!

Thanks, I really am going to complete the Nu-Rex series as soon as I can. Just have a lot going on now. I really want to get the B distributor into a video, I think a lot of people don't quite understand how it differs from the A.

[JimZ]

My grandfather installed a B distributor on my (inherited in 1990) ‘31 coupe in 1951. In ‘73 when we started the restoration my dad told me it ran great with the B distributor so we left it on. We always set timing to 5 deg. advance at 500 rpm with timing light. Since then, after about 3,000 miles it still runs good but now I’m wondering how much better it might run with an A distributor. Just picked up an A distributor, cable and spark rod at Pate so can’t wait to try it out.

[jack backer]

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Like anything else, with proper maintenance you will get good results with the B distributor. It does suffer from lack of lubrication so it’s a good idea to disassemble it and lube the flyweight pins and inner shaft. If the engine “rattles” under load back off the idle timing, you can be at 0 degrees at 500 rpm, if you detonate at high rpm under load.

The A distributor is foolproof, other than the timing is fixed where it’s set, you don’t get automatic spark control based on rpm..