Assembling distributors...

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kare
Posts: 547
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Location: Helsinki, Finland, Europe

Assembling distributors...

Post by kare »

Does anyone know the correct procedure for assembling the distributors? The timing can be changed/adjusted by 4 different set-ups:

1) position of angle drive
2) adjustment at the end of the distributor shaft (plus/minus 10 degrees?)
3) placing of contact breaker base plates
4) rotating the distributor body

- Is the correct position of angle drives documented anywhere?
- My passenger side distributor is retarded by 10 degrees (max) and driver side is advanced by 10 degrees (max). This ads up to 20 degrees. Driver side should run 30 degrees advanced to the passenger side; where is the last 10 degrees?

Setting the timing right is pretty easy, but Iäd sill like to know how it was originally assembled!

Best wishes, Kare
250 GT 2+2 3197/GT
John Vardanian
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Re: Assembling distributors...

Post by John Vardanian »

Hi Kare,

It looks like no answers are forthcoming... why don't you remove the beveled gears, reposition and reinsert them? Theoretically, with the gears in the right place, the foot adjustments and the point plates in middle position, the distributor flanges will line up exactly with the angle drive flanges.

john
PF Coupe
kare
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Re: Assembling distributors...

Post by kare »

Yes, this is what I am going to do - and should not be too hard. I was just wondering if there are some kind of markings or a documented way to set things up...
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tyang
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Re: Assembling distributors...

Post by tyang »

kare wrote:Yes, this is what I am going to do - and should not be too hard. I was just wondering if there are some kind of markings or a documented way to set things up...
Hi Kare,

With your distributors mounted with the plug wires exiting towards the front of the engine, the 1-6 rotor should be pointing forward at about 7 0'clock close to #1 spark plug wire when the engine is at #1 TDC. (make sure the flywheel and cam are on their marks if you're timing everything for the first time) The 7-12 rotor should be slightly behind (30 degrees) in position in relation to the other distributor. As you described, there are several ways to adjust this position, but the final position of the rotor with enough room for adjustment of the timing is what you're after.

Tom
'63 330 America #5053
kare
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Re: Assembling distributors...

Post by kare »

The car was in running condition when it was parked years ago, but after seeing all the abuse inside distributors, I think it is wise to go all the way. It is possible that the angle drives were put in in wrong position and this is why base plates were moved, distributor bodies rotated, etc...
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tyang
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Re: Assembling distributors...

Post by tyang »

kare wrote:The car was in running condition when it was parked years ago, but after seeing all the abuse inside distributors, I think it is wise to go all the way. It is possible that the angle drives were put in in wrong position and this is why base plates were moved, distributor bodies rotated, etc...
It's quite possible. It's real easy to jump a tooth on the angle drive if things are not installed carefully.

Tom
'63 330 America #5053
AndrewW-G
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Re: Assembling distributors...

Post by AndrewW-G »

Would suggest that it may be worth having your distributors setup / tested on a distributor machine (the old Sun ones) at the worst it will be easier to spot what's wrong
400 "30897" " Mondial "45461" & lots of other peoples toys at work
kare
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Re: Assembling distributors...

Post by kare »

Heh, on my distributors it was very easy to spot what was wrong :op

I've been tempted to buy an old Sun machine, but at this point I'm pretty satisfied with having set the distributors up using a few hours on a degree plate. A proper testing would off course provide advance curves, but I still think that eventual problems will occur in a very narrow RPM window - and if they do, I'll just run faster.

BTW, does anyone know at which position the adjustment pieces at the end of distributor shafts were originally set up. As said earlier, one of mine is advanced to max, and the other one is delayed to max. Does not make much difference, but would still be nice to know how they set it up originally...
250 GT 2+2 3197/GT
John Vardanian
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Re: Assembling distributors...

Post by John Vardanian »

Hi Kare,

Happy new year… how cold is Helsinki today?

If luck were on your side someone here would be in the middle of distributor work and would take note of the positions for you. I will be doing this around June/July if you can wait.

But, I think one way to put the adjustments is like this, coarse, medium and fine; where coarse is the beveled gear adjustment, medium is the distributor foot adjustment, and fine is the point plates adjustments. I don't think there is definite answer to your question.

For what it's worth, distributor speed being one-half of crankshaft speed, I have learned that dwell and interval settings at 2000 distributor RPM, as opposed to 400 RPM makes for a lot livelier engine at high speed cruising. So, it's hard to beat units that have been set on the Sun.

john
PF Coupe
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carello
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Re: Assembling distributors...

Post by carello »

kare wrote:Does anyone know the correct procedure for assembling the distributors? The timing can be changed/adjusted by 4 different set-ups. Best wishes, Kare
Hi Kare, What exact model Marelli distributors are you working with? I am trying to find more specific data for my Marelli listings- http://www.miuraworkshop.com/tavmarelli ... tions.html
Thanks
Craig
kare
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Re: Assembling distributors...

Post by kare »

Hi John, we've had up to -10 degrees Celcius or so. Now at +4.

I am not sure the point plates are ment for adjusting. I think they are there so the same basic distributor can be easily modified to work on a uneven firing engine. Many V6-engines run cylinders in three pairs and adjustable points plates provide an easy solution to produce a special distributor needed for such an engine! Remember Lancia was pioneering with V6-engines at the time (I don't know they were using).

Craig, I am working on a pair of S85A, which are original equipment on a Ferrari 250 GT 2+2. I also recently saw a 250 GT TdF (Ferrari engine tipo 128C from 1957), which is using Marelli ST.100 DTEM-E 12V (data plates were pretty worn, but I am 99% sure that is what they say). They look pretty identical to mine, but I was not able to look inside, off course. Like S85A they also run clockwise.

John, do you know what exact type of Marellis is your PF Coupé using?

Best wishes, Kare
250 GT 2+2 3197/GT
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carello
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Re: Assembling distributors...

Post by carello »

kare wrote:Craig, I am working on a pair of S85A, which are original equipment on a Ferrari 250 GT 2+2. Best wishes, Kare
Hi Kare, Can you post a picture of the Marelli S85A tags?Image
Best regards
Craig
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carello
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Re: Assembling distributors...

Post by carello »

Page 15 of this 66 page manual shows a S85A advance curve http://www.ferrari250gte.com/i/Manuals_ ... nzione.pdf. Is there a better advance curve posted? or can someone post a nice S85A advance curve?
thank you
Craig
John Vardanian
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Re: Assembling distributors...

Post by John Vardanian »

Hi Kare,

My PF coupe's distributors are S85A.

john
PF Coupe
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