Distributor drum 'pitting'?

It needs more frequent service.

I have welded and ground back to shape many of those drums. I am not aware of a source for new pins but have not tried in a long time. I would ask Motion Products or Pat Ottis and ask if they have a source. Motion Products makes quite a few Ferrari specific parts. They may actually make them.


You are going to need a distributor machine to resyncronize the advance curves when you are done.

 

Maybe all things considered it would be best to send the job to people who have done it before. Adjusting the advance curve and matching the two distributors advance curves is without a doubt best done by those familiar with the job. It is a pain in the ass and needs someone who knows how to do it and understands its importance so he doesn't just get to a place where he says "good enough". His reluctance to fix the drum is enough to make me question his suitability for the job.

 

Plenty for sale on fleabay. This was the cheapest so far and accepts offers;

http://pages.ebay.com/link/?nav=item.view&alt=web&id=151459431212

 

It's a finicky job but not particularly difficult. The little divots can be TIG welded and resurfaced easily. Pins are a simple job to make. Getting the advance curve set up requires the right combination of springs, shims and patience.

 

So for $800 he gets more of the same?

Not sure that sounds like a good deal.

 

Perhaps the distributor is half full? I know it's on eBay so it's gotta be bad. However in this particular case returns are accepted so .......

 

The pins should be very hard

After the guy who is used to recurving old Delco distributors is finished taking a Marelli apart for the 6th time to get it pretty close to the right curve how close is he going to get the second one?

Better off giving it to someone who knows what he is getting into.

 

I've done a few. You're right about taking them apart a few times. A pain in the ass but I don't know of a better way.

 

I posted a procedure for adjusting the advance several years ago. Gerret incorporated it into his 308/GT4 website, but that appears to have disappeared. PM me and provide an email address and I'll send it to you.

 

There's not but how many that are not Italian exotic people are going to that much trouble?

 

There is a very good chance one of those names I gave you has a bin box full. Why reinvent the wheel?

 

I still haven't figured them completely out but I love my distributors!I know this the factory used some king of locktite on all the screws and upon taking one apart for the first time it can be challenge I ended up using a small torch to heat the screw head....
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Superformance sells a kit where these pins are included. Ignition Parts for Ferrari 308, 208, 288 GTO & F40 - Superformance

 

The only issue you may encounter is that a rounder head will stack the spring assembly that much taller in the bore(s) of the weights, causing the points cam armature to rotate that much further inward (basically, you'll end up with more than the 16 degrees of distributor advance, or whatever else is spec'd for your model). This will cause the weights to bottom out further on the inner plastic bushing (and they crack easily).

I've tried to weld the pins/cups before unsuccessfully. To restore a proper advance curve, I just used very thin, very small washers/shims under the pin's heads to to take up the wear from the pins and cups. Requires lots of tear-downs and shuffling of washers to get the right advance curve. RPITA. I can't live without my Allen Syncrograph dizzy machine!

https://www.youtube.com/watch?v=_LvmcAEKcyY

 

The japanese distributor has only 3 pins and my car was hotrodded to have only two. I tried the correct set up but ended up going back to what I had as the car drive better and accelerates smoother. Setting these up is a real art and their are only a few around that still know how to do it. Having access to a machine and lots of time makes things easier. A lister here was involved with a new company making a modern machine if you are interested pm me and and I will pass you on. It was featured on a Jay Leno video. I also have a source that rebuilds and sells the sun machine I bought mine from him and what he does is fantastic!
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Okay, I kind-of get what you're saying. It may work doing that. I suspect though, that if the build up was not perfectly hemispherical, the strobe lights on the dizzy machine may jump around a bit, due to the possibility of the pin rotating due to engine vibration (trying to find a natural resting place). I was getting this issue when my distributors were really worn out. Like Rob Garven, I picked up a set of the S159Cs and unlike him, I got mine set up fine (using only two pins/springs combos). Although that was a couple of thousand miles ago, so I suspect some wear when I take them out this winter for my annual service/tune-up (photos are of my original set of S159Bs).
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Peter did you use the 159C cam that came with the unit? Dan I am not an engineer but would assume if you made the heads bigger the wear areas would just be larger? As stated earlier superformance has the repro pins in stock. I have had at least 5 sets of distributors, even s a set professionally rebuilt, but the car still runs better with the original ones from PO with the two pin set up.