dual point timing, 330 with S85 Dist.

[Jumprun]

I would like to make sure the second set of points in each distributor is timed (theoretically) at 180 degrees from the first set. I can put a timing light or static test light on the appropriate cylinder for the second set, but is there a trick to moving the point mounting plate? mine fit pretty tight to the distributor housing, and I can see it might be difficult to move them easily in the car.

Is there a way to accurately adjust them on the bench without a distributor machine? The plates do have slots on each end so there is considerable potential to get several degrees of adjustment.

I don't remember seeing anything in the shop manual. Am I getting too fussy? or should I just center the mounting plate slots over the tapped holes in the body and be happy?

P.S. I used to have a 1931 Lincoln model K, it was a V8 with a dual point distributor and ignition system, just like our Ferraris, but it had adjustment screws to individually adjust each set of points accurately.

Thanks all, Tom in So Cal.

[tyang]

Hi Tom,

Getting the points plates phased in correctly is crucial. A couple of degrees either way will amplify as engine speed increases. Ferraris build the most power above 3-4K and you can imagine how much power is lost when half the cylinders are firing behind or ahead of the others. With four sets of points, you can have four sets of cylinders out of time. The only way to do this properly is on a distributor machine.

Tom

[330Jim]

I agree it is very important to get them set correctly. You can check them on the car with a timing light, just need to made sure cylinders 1, 6, 7, and 12 are all set to the same advance relative to TDC. If 6 does not match 1 then the phase is off, same with 7 and 12. To set them it is much easier to do off the car. I have had good success removing the rotor and replacing it with a degree wheel. Then I spin the distributor slowly while listening to an audible continuity tester. When it goes quiet I know the points are opening, that needs to occur every 60 degrees if the points are set right. I check over one or two rotations to make sure I am consistent. It requires a delicate touch. I often find them off doing this method. Note these are distributor degrees, every degree that it is off by is two crank degrees so it needs to be spot on.

Cheers Jim

[John Vardanian]

I have seen it done this way. This is essentially a homemade Sun machine:

1. Make a ring out of cardboard that fits tightly around the distributor body.
2. Graduate this ring like a compass at 60 degree segments.
3. Securely fix a pointer onto the rotor that corresponds to the compass.
4. Connect a light and battery to the distributor.
5. Block one set of points by placing a piece of paper in between the contacts.
6. Spin the distributor slowly by hand. You'll notice that the light will blink on and off.
7. Now, start your test by slowly turning the rotor till the light comes on and stays on.
8. While the light is on, rotate the cardboard compass so the pointer on the rotor points to zero.
9. Continue turning the rotor slowly and you'll notice that the light blinks again at 120 degrees, 240 degrees and then again at zero degrees. In other words, the light will blink three times on a full revolution, equally timed apart.
10. Now, blank the second set of points (while un-balnking the first set) and repeat the test.
11. If the two contact points are synchronized, the light will blink when the pointer points at 60 degrees, 180 degrees and then at 300 degrees.
12. If the bulb lights at anything less or more, loosen the points plate of the live set of points and move it till it lights at 60-180-240. A perfectly synchronized distributor will light up your light bulb at 0-60-120-180-240-300-360 degrees, or at every 60 degree increments.

Note: you need to set your points gap before you start this exercise. The points plate should slide freely back and forward once the two hold-down screws are loosened. If they bind, look for a flaw. If there is no flaw, take fine sand paper and rub at the outer rims lightly and carefully. It's very important that the plate fits perfectly-- not loose, not tight.

Good luck.

john

[DWR46]

John's reply is good. However, you should EXPECT to have the point gap (dwell) change as you move the point plate. In theory it should not happen, but in reality it almost always does. So you find yourself chasing both phasing and dwell as you set up the distributors. That is why a Distributor machine is the only good way to do this.

[Jumprun]

Thanks guys, the replies confirm exactly what I was thinking, that I need to make sure both sets of points are accurately timed. I'm surprised there is nothing about this in the GTC manual.

--Tom in Socal.

[John Vardanian]

Dyke, you are right, there is no real substitute for a Sun distributor machine when it comes these distributors. If you don't have a Sun but have all the time in the world, the cardboard ring trick is not so bad.

john

[tyang]

Statically timing your points will get you in the ball park, but things change when the engine is running. I initially static time the ignition systems before I fire up an engine for the first time using a test light to determine exactly when the points open for a timing event on AF 10 to get in the ballpark, but I guarantee there is always a little bit of tweaking of the distributor timing once the engine is running. It's very rarely spot on to my static time. The same goes for the phasing.

For a guy who went out and bought six synchrometers to balance his carbs, I'm surprised John that you compromised on phasing of your distributor points! (Good nature ribbing).

Tom

[John Vardanian]

No compromises here, I got my own Sun 540. But I don't think our friend who asked for help does. Browbeating is something you get on Ferrari Chat when you as much as drop a hint about doing something on your car yourself.

john

[tyang]

Hi John,

I figured you would have owned a Sun Machine!

Browbeating, and ribbing are very different things! I am always supportive of guys doing their own work with the knowledge of efficiency and pragmatism!

Carry on.

Tom

[John Vardanian]

Tom (in So Cal), the Ferrari manual I have from the 1970's (by Rousch and Apen) does tell you how to synchronize the points on the car. I can email you copies of those pages if you send me a PM. Thanks.

john

[Jumprun]

John, I have that book! Thanks.
It confirms what I had planned to do, not exactly, but it should yield the same results, especially if I confirm everything with the car running and a timing light.

Tom in SoCal

[Pied-Noir]

<t>Since I wasn't planning on racing at Le Mans, I used a very simplified version of a timing machine. Basic? Quite so, but it served my purpose and works quite well. The protractor was the right size and came out of my old drafting kit. The pointer is an old rotor with a sharpened paper clip. <br/>
Just for fun!<br/>
P/N</t

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