Capacitive Discharge Ignition System Resto
April 5th, 2015, 09:21 AM
#1
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Capacitive Discharge Ignition System Resto
Beginning the the resto on my'67 4-4-2 post car.
Want to install the original CDI system which was removed years ago when it malfunctioned.
Diagnosis was a bad power transistor in the power module.
Does anyone know where a correct transistor can be had for one of these or who might be doing resto work on them?
Want to install the original CDI system which was removed years ago when it malfunctioned.
Diagnosis was a bad power transistor in the power module.
Does anyone know where a correct transistor can be had for one of these or who might be doing resto work on them?
April 5th, 2015, 10:12 AM
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April 5th, 2015, 10:28 AM
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The original transistors in these boxes are Germanium. Germanium transistors are old technology and were replaced by Silicon. You may be able to source a replacement Germanium but you will still have reliability concerns. There is a seller on ebay who machines the housing to accept a modern replacement board which was designed for the Corvette Transistorized Ignition (TI) system. However, since the Corvette used a mechanical tachometer they add a second board to drive the tachometer. http://www.ebay.com/itm/67-GTO-67-68...-/171739261508 As you can see, this service is not cheap.
I am working on getting a UHV system running on a friend's 1968 W-30. I have been in discussions with a tech from the Corvette world who uses GM HEI modules to replace the Corvette TI electronics. He bypasses the whole system by mounting the HEI module directly to the TI distributor. Our thought is to replace the board in the UHV box with a HEI module and use the correct wiring. We should be able to try it early this week. I will post the results.
I am working on getting a UHV system running on a friend's 1968 W-30. I have been in discussions with a tech from the Corvette world who uses GM HEI modules to replace the Corvette TI electronics. He bypasses the whole system by mounting the HEI module directly to the TI distributor. Our thought is to replace the board in the UHV box with a HEI module and use the correct wiring. We should be able to try it early this week. I will post the results.
Beginning the the resto on my'67 4-4-2 post car.
Want to install the original CDI system which was removed years ago when it malfunctioned.
Diagnosis was a bad power transistor in the power module.
Does anyone know where a correct transistor can be had for one of these or who might be doing resto work on them?
Want to install the original CDI system which was removed years ago when it malfunctioned.
Diagnosis was a bad power transistor in the power module.
Does anyone know where a correct transistor can be had for one of these or who might be doing resto work on them?
April 5th, 2015, 11:34 AM
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April 5th, 2015, 11:56 AM
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In most cases circuits designed for Germanium transistors will not work with Silicon. The electrical characteristics of the two materials are different and require a redesigned circuit to work. That is what the new Corvette TI boards are. Someone redesigned the circuit for silicon semiconductors.
In my opinion if someone is using an original box they are gambling every time they head out in the car. The original transistors often failed in the first few years of service. A modern silicon based solution is reliable and should last a long time.
In my opinion if someone is using an original box they are gambling every time they head out in the car. The original transistors often failed in the first few years of service. A modern silicon based solution is reliable and should last a long time.
Last edited by Boiler_81; April 5th, 2015 at 01:58 PM.
April 5th, 2015, 12:00 PM
#7
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^^^This. There's no reason to screw with a aftermarket repro board. Just use a commonly available HEI module inside the original UHV housing. I'm planning on doing this with a non-functional housing I picked up cheap recently.
April 5th, 2015, 07:12 PM
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In most cases circuits designed for Germanium transistors will not work with Silicon. The electrical characteristics of the two materials are different and require a redesigned circuit to work. That is what the new Corvette TI boards are. Someone redesigned the circuit for silicon semiconductors.
In my opinion if someone is using an original box they are gambling every time they head out in the car. The original transistors often failed in the first few years of service. A modern silicon based solution is reliable and should last a long time.
In my opinion if someone is using an original box they are gambling every time they head out in the car. The original transistors often failed in the first few years of service. A modern silicon based solution is reliable and should last a long time.
When the system failed, the car was less than 3 years old and had less than 30,000 miles.
If I were to adapt the new Corvette TI board, would the distributor module also have to be changed?
When you call it ".....new Corvette TI boards........", what year(s) do you mean?
I assume you mean newer that the 1st generation '64-'71 K66 Corvette system.
I'd really like to keep as much of the original hardware as possible for appearance.
I guess my question is how far will I have to deviate from original to do an upgrade like this?
Last edited by 67442nut; April 5th, 2015 at 07:45 PM.
April 5th, 2015, 07:36 PM
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I sent my points distributor and UHV box to Distributor Dave. He converted my dist. to HEI, and installed the HEI module in the UHV box. It has plenty of wiring to mount the box to the front rt. passenger inner fender like original, and plug into the distributor. My new Lectric Limited wiring harness was made for HEI instead of points. I hope it all works out good, come time to use it. Ill just carry a spare module in the glove box, just in case. The guys name is Dave Ray, It took him about 2 months, but he cleaned and rebuilt the distributor. I found 2 of the original red NOS distributor caps on EBAY, bought them both. Ill paint my coil red to match, so it will look like factory UHV, only better... I hope.
Steve
Steve
April 6th, 2015, 05:16 AM
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See below
As I said in my first post, I believe the easiest way to do this is to replace the board in the UHV housing with an HEI module. I plan on doing this very modification this week. I will let you know how it goes.
You're correct.
When the system failed, the car was less than 3 years old and had less than 30,000 miles.
If I were to adapt the new Corvette TI board, would the distributor module also have to be changed?
I am confident the UHV distributor will work with the HEI module with no modification. The Corvette guy I yhave been talking with used the original TI distributor when making the modification to the Corvette system.
When you call it ".....new Corvette TI boards........", what year(s) do you mean?
I assume you mean newer that the 1st generation '64-'71 K66 Corvette system.
The boards I am talking about are new design replacement boards built with modern components for the early (64-71) Corvette TI system.
I'd really like to keep as much of the original hardware as possible for appearance.
I guess my question is how far will I have to deviate from original to do an upgrade like this?
When the system failed, the car was less than 3 years old and had less than 30,000 miles.
If I were to adapt the new Corvette TI board, would the distributor module also have to be changed?
I am confident the UHV distributor will work with the HEI module with no modification. The Corvette guy I yhave been talking with used the original TI distributor when making the modification to the Corvette system.
When you call it ".....new Corvette TI boards........", what year(s) do you mean?
I assume you mean newer that the 1st generation '64-'71 K66 Corvette system.
The boards I am talking about are new design replacement boards built with modern components for the early (64-71) Corvette TI system.
I'd really like to keep as much of the original hardware as possible for appearance.
I guess my question is how far will I have to deviate from original to do an upgrade like this?
April 6th, 2015, 05:20 AM
#11
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Join Date: May 2008
Location: SE MI
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I sent my points distributor and UHV box to Distributor Dave. He converted my dist. to HEI, and installed the HEI module in the UHV box. It has plenty of wiring to mount the box to the front rt. passenger inner fender like original, and plug into the distributor. My new Lectric Limited wiring harness was made for HEI instead of points. I hope it all works out good, come time to use it. Ill just carry a spare module in the glove box, just in case. The guys name is Dave Ray, It took him about 2 months, but he cleaned and rebuilt the distributor. I found 2 of the original red NOS distributor caps on EBAY, bought them both. Ill paint my coil red to match, so it will look like factory UHV, only better... I hope.
Steve
Steve
Last edited by Boiler_81; April 7th, 2015 at 05:17 AM.
April 6th, 2015, 06:04 PM
#12
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I can confirm the HEI module works with the original UHV distributor and coil.
1.) The White distributor pick up coil wire goes to (W) on HEI module
2.) The Green/White distributor pick up coil wire goes to (G) on HEI module
3.) (+) on the coil goes to (B) on the HEI module
4.) (-) on the coil goes to (C) on HEI module.
5.) Ground the HEI module and make sure it is mounted flush to a heat sink using thermal paste
6.) (+) side of coil to ignition switch 12 volts
We have removed the original board from the UHV box and are making a mounting plate/ heat sink to bolt into the box. I will when route through the UHV wiring harness to the correct points on the coil and distributor. I believe some of the wires in the system are resistance wires which will have to be replaced with standard wire. I will post an update when the box is running with the HEI installed
1.) The White distributor pick up coil wire goes to (W) on HEI module
2.) The Green/White distributor pick up coil wire goes to (G) on HEI module
3.) (+) on the coil goes to (B) on the HEI module
4.) (-) on the coil goes to (C) on HEI module.
5.) Ground the HEI module and make sure it is mounted flush to a heat sink using thermal paste
6.) (+) side of coil to ignition switch 12 volts
We have removed the original board from the UHV box and are making a mounting plate/ heat sink to bolt into the box. I will when route through the UHV wiring harness to the correct points on the coil and distributor. I believe some of the wires in the system are resistance wires which will have to be replaced with standard wire. I will post an update when the box is running with the HEI installed
April 6th, 2015, 07:30 PM
#13
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I didnt have the UHV distributor, only the UHV box. Joe P. told me about Dave Ray, alot of Buick and Pontiac guys have used him too. He can convert a points distributor to HEI or MSD. Other than the wrong numbers on the housing, it will look like an original UHV. He can also put the MSD parts in the UHV box if converting an original points to MSD. Parts for both are easy to get if needed.
Steve
Steve
April 6th, 2015, 08:01 PM
#14
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If I were to adapt the new Corvette TI board, would the distributor module also have to be changed?
I am confident the UHV distributor will work with the HEI module with no modification. The Corvette guy I have been talking with used the original TI distributor when making the modification to the Corvette system.
As I said in my first post, I believe the easiest way to do this is to replace the board in the UHV housing with an HEI module. I plan on doing this very modification this week. I will let you know how it goes.
If I were to adapt the new Corvette TI board, would the distributor module also have to be changed?
I am confident the UHV distributor will work with the HEI module with no modification. The Corvette guy I have been talking with used the original TI distributor when making the modification to the Corvette system.
As I said in my first post, I believe the easiest way to do this is to replace the board in the UHV housing with an HEI module. I plan on doing this very modification this week. I will let you know how it goes.
I was into 'vettes years ago and had a K66 TI system.
I noticed then that the distributor module looked the same as the 4-4-2's CDI distributor,
so, if he used the original Corvette distributor with the new module,
then the CDI distributor should work as well.
Some pics of the new module installed in the old CDI box would be nice.
Did your guy say if the original wiring harness could be used?
Do you know who makes/sells the new module, GM or aftermarket?
Is this what we're talking about?
http://www.ebay.com/itm/TRANSISTOR-I...item2edf29952b
Sorry for all the questions, but, this sounds like a very good alternative
to restoring the old module.
Last edited by 67442nut; April 6th, 2015 at 08:18 PM.
April 6th, 2015, 08:32 PM
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I didnt have the UHV distributor, only the UHV box. Joe P. told me about Dave Ray, alot of Buick and Pontiac guys have used him too. He can convert a points distributor to HEI or MSD. Other than the wrong numbers on the housing, it will look like an original UHV. He can also put the MSD parts in the UHV box if converting an original points to MSD. Parts for both are easy to get if needed.
Steve
Steve
I have a spare MSD 6AL.
I wonder if the original CDI distributor and coil can be reused
if the CDI amplifier is upgraded with the MSD guts.
April 7th, 2015, 03:55 AM
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Take a look at the ebay auction for the upgrade http://www.ebay.com/itm/67-GTO-67-68...item27fc752a44
The auction above has a photo of the Corvette TI reproduction Amp board installed in an Ods UHV housing. It will use the factory harnesses.
There are a couple of sellers of the Corvette TI module. The problem is they don't have tachometer drive circuitry as the Corvette was a mechanical drive tach. The ebay seller above is the only one I have seen who adds a way to drive the electric tach which is in the 442 and GTO.
The auction above has a photo of the Corvette TI reproduction Amp board installed in an Ods UHV housing. It will use the factory harnesses.
There are a couple of sellers of the Corvette TI module. The problem is they don't have tachometer drive circuitry as the Corvette was a mechanical drive tach. The ebay seller above is the only one I have seen who adds a way to drive the electric tach which is in the 442 and GTO.
I'm pretty sure you're right about the distributor.
I was into 'vettes years ago and had a K66 TI system.
I noticed then that the distributor module looked the same as the 4-4-2's CDI distributor,
so, if he used the original Corvette distributor with the new module,
then the CDI distributor should work as well.
Some pics of the new module installed in the old CDI box would be nice.
Did your guy say if the original wiring harness could be used?
Do you know who makes/sells the new module, GM or aftermarket?
Is this what we're talking about?
http://www.ebay.com/itm/TRANSISTOR-I...item2edf29952b
Sorry for all the questions, but, this sounds like a very good alternative
to restoring the old module.
I was into 'vettes years ago and had a K66 TI system.
I noticed then that the distributor module looked the same as the 4-4-2's CDI distributor,
so, if he used the original Corvette distributor with the new module,
then the CDI distributor should work as well.
Some pics of the new module installed in the old CDI box would be nice.
Did your guy say if the original wiring harness could be used?
Do you know who makes/sells the new module, GM or aftermarket?
Is this what we're talking about?
http://www.ebay.com/itm/TRANSISTOR-I...item2edf29952b
Sorry for all the questions, but, this sounds like a very good alternative
to restoring the old module.
April 7th, 2015, 04:00 AM
#17
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OK that makes sense. On the car I'm working on, the correct numbered and dated distributor was with the system so we wanted to use it.
I didnt have the UHV distributor, only the UHV box. Joe P. told me about Dave Ray, alot of Buick and Pontiac guys have used him too. He can convert a points distributor to HEI or MSD. Other than the wrong numbers on the housing, it will look like an original UHV. He can also put the MSD parts in the UHV box if converting an original points to MSD. Parts for both are easy to get if needed.
Steve
Steve
October 25th, 2016, 06:21 PM
#18
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Posts: 1,584
For anyone interested, i just talked to Dave Ray today. Hes still in business and doing well, hes a hoot to talk to, pretty smart guy i think. Anyway, his old web site is down and hes working on getting a new site up. His new email address is
info.davessmallbodyheis@gmail.com
phone# 775-722-3294
He did my distributor and put the HEI module in an original UHV box. The distributor has an MSD magnetic pickup. Seems to work great. When i did it the cost was $205, very reasonable i think.
Anyway just passing this on to anyone interested in the conversion. Dave said it was alright to post this info.
Steve
info.davessmallbodyheis@gmail.com
phone# 775-722-3294
He did my distributor and put the HEI module in an original UHV box. The distributor has an MSD magnetic pickup. Seems to work great. When i did it the cost was $205, very reasonable i think.
Anyway just passing this on to anyone interested in the conversion. Dave said it was alright to post this info.
Steve
October 26th, 2016, 10:44 AM
#19
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If you had the schematic for the CDI, I would be able to look at it and give you the new part numbers. The guy is right if that thing had a germanium output transistor. If the base signal of transistor only goes to .3 vdc it will not turn a silicon transistor on. However it may be possible to just change a resistor or two to make the silicon transistor work.
October 26th, 2016, 02:35 PM
#20
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If you had the schematic for the CDI, I would be able to look at it and give you the new part numbers. The guy is right if that thing had a germanium output transistor. If the base signal of transistor only goes to .3 vdc it will not turn a silicon transistor on. However it may be possible to just change a resistor or two to make the silicon transistor work.
If you EVER have the registration number for any tranny (aka like 1Nxxxx or 2Nxxxx or 2SA-D etc, you can enter them into google and get a few webpages the suggest replacements. You have to know a little bit to just swap them out, but since this is not audio or data, we are not so much worried about speed and since the original was Ge, Ic aint gonna be an issue.
December 27th, 2016, 02:08 PM
#21
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Did you ever get your box up and running well with the module?
Did you have to replace the wires with standard wires?
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