[C2] Distributor length
Thread Starter
Race Director
Joined: Nov 2003
Posts: 10,696
Likes: 3,090
From: Cottonwood AZ
C1 of Year Finalist (performance mods) 2019
[QUOTE=4 Speed Dave;1604936394]The OEM TI systems were fussy which is why I couldn't believe that my car actually started after being put up on blocks for 28 years when I got it running. I would have for sure thought the amp box would be shot but no it all worked and ran. I still have all the TI parts on a shelf as I went with a full MSD system.[/QUOTE
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Drifting
Joined: Nov 2016
Posts: 1,964
Likes: 579
From: Pittsburgh PA
i am with nowhere man here, and it has been explained on this forum several times. I do not see any reason why a standard dizzy cant be converted. they even sell a conversion kit to do it.
https://www.ebay.com/itm/25301281150...AAAOSw7GRZA3ip
and here is an old thread i started, duke answered explaining they could be converted
https://www.corvetteforum.com/forums...-question.html
Edit- unless you are talking about the dizzy you posted a pic of in the first photo. maybe there is a weird issue between that particular dizzy and the vette cast iron dizzys?
https://www.ebay.com/itm/25301281150...AAAOSw7GRZA3ip
and here is an old thread i started, duke answered explaining they could be converted
https://www.corvetteforum.com/forums...-question.html
Edit- unless you are talking about the dizzy you posted a pic of in the first photo. maybe there is a weird issue between that particular dizzy and the vette cast iron dizzys?
Last edited by Tiger Joe; Mar 30, 2022 at 12:45 PM.
Thread Starter
Race Director
Joined: Nov 2003
Posts: 10,696
Likes: 3,090
From: Cottonwood AZ
C1 of Year Finalist (performance mods) 2019
i am with nowhere man here, and it has been explained on this forum several times. I do not see any reason why a standard dizzy cant be converted. they even sell a conversion kit to do it.
https://www.ebay.com/itm/25301281150...AAAOSw7GRZA3ip
and here is an old thread i started, duke answered explaining they could be converted
https://www.corvetteforum.com/forums...-question.html
Edit- unless you are talking about the dizzy you posted a pic of in the first photo. maybe there is a weird issue between that particular dizzy and the vette cast iron dizzys?
https://www.ebay.com/itm/25301281150...AAAOSw7GRZA3ip
and here is an old thread i started, duke answered explaining they could be converted
https://www.corvetteforum.com/forums...-question.html
Edit- unless you are talking about the dizzy you posted a pic of in the first photo. maybe there is a weird issue between that particular dizzy and the vette cast iron dizzys?
That may be the issue. I have not put a magnet on it but the casting LOOKS like it is aluminum not cast iron. Also I would not spend $450. for a conversation kit either.
Safety Car
Joined: May 2014
Posts: 3,784
Likes: 656
NOPE! As I said both my mechanic and the machine shop said it could not be done. I have a freshly rebuilt tach drive distributor for the car and they had both of them side by side. I don’t recall EXACTLY why it could not be done so if you know all the particulars rather than just something you read in a book and can tell me HOW I have to go with what they said.
Nowhere man is correct if you have a cast tach drive distributor, it's the same housing as the points distributor.
Tech Contributor
Joined: Jun 2004
Posts: 20,910
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
NOPE! As I said both my mechanic and the machine shop said it could not be done. I have a freshly rebuilt tach drive distributor for the car and they had both of them side by side. I don’t recall EXACTLY why it could not be done so if you know all the particulars rather than just something you read in a book and can tell me HOW I have to go with what they said.
We're all happy to help, but your plan is a bit confusing.
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,271
NOPE! As I said both my mechanic and the machine shop said it could not be done. I have a freshly rebuilt tach drive distributor for the car and they had both of them side by side. I don’t recall EXACTLY why it could not be done so if you know all the particulars rather than just something you read in a book and can tell me HOW I have to go with what they said.
I've personally made a conversation less than a year ago, but what do I know? There are a lot of so-called "professionals" out there than have their heads up their ***...es. I've recently posted the complimentary parts that need to be swapped to convert one way or the other.
Duke
Racer
Joined: Mar 2008
Posts: 338
Likes: 19
From: Mesa Az
That was the Delcotronic CD ignition system introduced in 67 on Olds and Pontiac, not to be confused with the Transistorized Ignition system used on Chevrolet vehicles. Looks like the distributor is not original to that application.
https://www.curbsideclassic.com/auto...points-part-2/
https://www.curbsideclassic.com/auto...points-part-2/
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,271
Yes, I have the SAE paper on that short lived CD ignition system. It was never available on ANY Chevrolet engine. If that dist. is original to the system it came off a Pontiac or Olds engine. Do they have different length dist. housings than Chevy engines? I don't know, but I wouldn't be surprised. The CD system did use the same magnetic pulse distributor parts... namely the stationary and rotating pole pieces.
I believe one of the reasons it was short lived is that CD systems are not a good architecture for emission controlled engines because even though the spark has a lot of energy, its duration is too short. Lean, low density mixtures need lots of spark duration to reliably light the fire. The GM CD system spark duration is only 35 microseconds... single point is 120, and I recall TI is 180 microseconds. (That's millionths of a second.)
Think about this if you consider a MSD system. Sure it offers multiple sparks at low to medium revs, but they're retarded 20 or more degrees. What good does that do? You want a system that lights the fire at least 99.99 percent of the time, and the single point system with a "blueprinted" distributor and the proper point set will work perfect to 7000 revs.
It's an "elegant system"... simple, inexpensive, and reliability gets the job done with some occasional simple maintenance.
Duke
I believe one of the reasons it was short lived is that CD systems are not a good architecture for emission controlled engines because even though the spark has a lot of energy, its duration is too short. Lean, low density mixtures need lots of spark duration to reliably light the fire. The GM CD system spark duration is only 35 microseconds... single point is 120, and I recall TI is 180 microseconds. (That's millionths of a second.)
Think about this if you consider a MSD system. Sure it offers multiple sparks at low to medium revs, but they're retarded 20 or more degrees. What good does that do? You want a system that lights the fire at least 99.99 percent of the time, and the single point system with a "blueprinted" distributor and the proper point set will work perfect to 7000 revs.
It's an "elegant system"... simple, inexpensive, and reliability gets the job done with some occasional simple maintenance.
Duke
Last edited by SWCDuke; Mar 30, 2022 at 09:40 PM.
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Thread Starter
Race Director
Joined: Nov 2003
Posts: 10,696
Likes: 3,090
From: Cottonwood AZ
C1 of Year Finalist (performance mods) 2019
As I said, I had PLANNED to use the TI parts out of this distributor to use in an original tach drive distributor I also have but the won’t work. Probably because this distributor has an aluminum casting.
Yes I know about these being available for Pontiac and Olds but a Pontiac distributor rotates the opposite way and the Olds distributor is shorter.
The machinist finally found an original Chevy TI distributor that he had been looking for during entire time and is going through it and has an old distributor machine that he is going to use on it all for $300. so a smoking deal so I now have a complete system with the NOS coil I just bought and a rebuilt amp. I will now sell the UHV system I have so all is good now.
Yes I know about these being available for Pontiac and Olds but a Pontiac distributor rotates the opposite way and the Olds distributor is shorter.
The machinist finally found an original Chevy TI distributor that he had been looking for during entire time and is going through it and has an old distributor machine that he is going to use on it all for $300. so a smoking deal so I now have a complete system with the NOS coil I just bought and a rebuilt amp. I will now sell the UHV system I have so all is good now.