Dino Saga 060625___Ignition Advance

Dino Saga 060625___Ignition Advance

Last week I talked about plugs, coils, coil drivers and points. Now let’s look at advance curves and mechanisms to get there from here. We have established that we can fire a good plug at any RPM that the engine can survive. In the Dino, 7800 is marked red on the dial and is conservative. If you look at HP curves, carbs and exhaust are starting to run out of breath there with stock cams. Let’s figure that that is plenty fast enough for highway driving. If you look at torque curves, torque is pretty flat from 3500 to 7800. Below 3000, torque took a holiday. The Dino will never be a dragster. That’s OK, you will catch him eventually and pass him easily when you do. Ferrari designed the car as a high speed tourer and matched cams and advance to give you that flat torque band and good acceleration at speed. Which finally gets us to advance.

Magneti Marelli is an ancient company and was the electrical supplier of choice for Ferrari for decades. Distributors, alternators, starters. If you have ever played with Lucas, Marelli is Nirvana. Built like a brick s..t house. Parts never fall off. Distributor is massively over designed and will last forever if lubricated. If the advance mechanism is not lubricated, it WILL self destruct. Not always literally; just that the advance will be stuck at full, none, or randomly wander in between. The chart shows what should be to get that flat torque curve and great driveability. If weights, springs and cam are lubed, not worn, then setting timing with a timing light is fine. As rpm increases, advance should rise to 10 degrees at 2,000 rpm then slowly and linearly increase to 30 deg at 5,500 rpm. Then stay at 30 deg to redline. Any jittering is bad. 30 degrees plus 6 degrees static is safe for 91 Octane gas and normal driving.

With an electronic coil driver, point dwell is not a concern. Points will last 30-40,000 miles. Electronic triggers are not worth the effort and add to complexity. If you want anything better for the advance curve, you have to go to a crank driven electronic system. The simpler ones I have researched do not allow matching the Ferrari curve. The more expensive ones allow use of the distributor and one coil or the choice of multiple coils and no distributor. Programming a curve is fun (not) and you have to run engine on dyno to find any area of improvement over the stock curve. Probably can’t. Life is too short. Besides it is fun to pull the distributor every 3 years or so. Keeps the juices flowing.

Pics show some of my horrible examples of what happens with not enough lube and/or the wrong materials. Current weights are from Superformance. Made of steel, unhardened, lousy workmanship. I polished, used old hardened spring pins rather than mild steel ones supplied. 5,000 miles so far and all OK as of 500 miles ago. Lots of lube. We will see.

Dinos are meant to be driven. Use a little tender loving care and yours can last forever. And keep up with the latest computer aided super cars with similar engine size. And look better doing it.

John
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See Dino Saga 060618 and earlier ones talking about distributor rebuild. Most info should apply to any Magneti Marelli distributor. A complication in other Ferrari models is the need to synchronize two distributors but this makes need for maintenance even more critical.

John

 

Mike's link has a great picture of all the pieces. There are two long springs, 2 short. Same with the center pins with the button heads. They only go together one way. Holes are different depth. Long springs are wound with heavier wire. Higher rate. Washers are added or removed to get advance curve just right. Remember that distributor runs at half crank speed so testing points are 500 RPM for weights to start moving. 1000 RPM for second spring to start compressing at 5 deg. advance. 2750 RPM for full weight travel and 15 degrees of advance. THESE ARE DISTRIBUTOR NUMBERS. You can do initial set-up without rotation. Adjust center plastic ring diameter for 15 degrees total advance. Adjust outer spring pin to just touch at 5 degrees advance. This can be done before installing guts in housing. From there you have to spin it. Again, see my Dino Saga or use a distributor machine.

Mike, the extra break point at 2000 RPM gives you a lot more oomph getting off the line. It is worth the extra playing around with the second spring.

I have tried a number of greases and finally went to wheel bearing grease for the weights and 3 & 1 oil on the bronze bushings inside the cam. Lots of grease! Instrument grease does not last.

John