250 Gte Distributor

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chris
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250 Gte Distributor

Post by chris » Mon Apr 13, 2020 6:02 am

Hi Tom & All,

happy easter to you.
I dismounted one 250 Gte distributor today to check for wear and found two different length of springs in the weights. See picture. Is this normal?

Thanks
Christopher
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enio45
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Location: Gilbert, AZ

Re: 250 Gte Distributor

Post by enio45 » Mon Apr 13, 2020 11:06 am

Chris, I cannot answer your question, but there is a guy in california that does all things distributors - Marelli is his speciality....i can't recall the name, but web search or marelli dist services and he should babble to answer your question.

i assume that is md 85 distributor?
Ed Montini
330 GT 2+2 Series II - 8289
58 Ellena - 0855GT - orig drivetrain

chris
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Re: 250 Gte Distributor

Post by chris » Mon Apr 13, 2020 1:31 pm

Hi Ed,

Thanks. I meanwhile have the answer. Yes, that is as it should be.

Thanks
Christopher

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tyang
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Re: 250 Gte Distributor

Post by tyang » Mon Apr 13, 2020 7:44 pm

Hi Chris,

As you have learned the different springs allow the weights to progressively advance the distributor as the speed increases.

Tom
'63 330 America #5053

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John Vardanian
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Re: 250 Gte Distributor

Post by John Vardanian » Tue Apr 14, 2020 1:09 am

Chris, that is correct, the pair of coil springs are not only unequal length but are also made of different gauge wires. There are also shims between the cups and the pins. These shims along with the tension of the coil springs, as well as the tension of the leaf springs dictate the profile of the advance curve. There should be an "X" scratched on one of the weights and another "X" scratched on the corresponding pivot pin. Then there is another "X" scratched on the lobe hub. Make sure the three X's" group together. When you take things this far apart, it's best to have the distributors re-calibrated. Good luck.

john
PF Coupe

chris
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Re: 250 Gte Distributor

Post by chris » Tue Apr 14, 2020 4:44 am

Hi John, Tom,

Thanks a lot. I had marked everything when I dismantled it as I was not aware of the factory markings. I have looked at the parts now and found all the ,X‘. I will definitely have both tested foe their advance curve before using them. Thanks for sharing your knowledge! That is bid help.

Christopher

chris
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Re: 250 Gte Distributor

Post by chris » Thu Jul 30, 2020 3:37 am

Dear All, dear Tom,

is this the right distributor advance curve for the 250 Gte? Thanks a lot.

Christopher
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chris
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Re: 250 Gte Distributor

Post by chris » Thu Jul 30, 2020 4:03 am

Just to add. This comes from the Service and Maintenance handbook but it irritates us as it does not corresbond with the manual data?

Thanks
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chris
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Re: 250 Gte Distributor

Post by chris » Thu Jul 30, 2020 11:34 am

Thanks, have needed info thanks to GTO. They informed me that the curve is identical to the 330Gt and provided attached table.

Thanks
Christopher
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abrent
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Re: 250 Gte Distributor

Post by abrent » Thu Jul 30, 2020 6:00 pm

The Distributor guy in CA is Tom Meadows.
https://marelliservice.com/contact-us

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John Vardanian
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Re: 250 Gte Distributor

Post by John Vardanian » Fri Jul 31, 2020 1:15 am

Chris, the centrifugal force starts moving the weights at about 500 RPM and at about 2500 RPM they have been flung out as far as they can go. So, in a standard distributor your advance starts at 1000 engine RPM and it maxes out at about 5000 engine RPM. Here is my reference for setting up the advance profile. This suggests that the max advance is at 4000 RPM, but my experience shows it goes a little past that.

john
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chris
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Re: 250 Gte Distributor

Post by chris » Fri Jul 31, 2020 3:33 am

Hi John,

Thanks. That curve is perfectly in line with the data from Gto. So we are on the same side.

Thanks a lot
Christopher

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