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Turns out the culprit was the new TI coil.. We stole the coil off of the 66' and put it on the 65', along with the 65's K&B TI box and the car ran great all day today. Idle was consistent and no dying...so evidently there is something wrong with a brand new repro coil.
We still have a few little odds and ends we need to finish, also may have a fuel delivery issue at high rpms as it seems to run out of fuel at 6k ish in 3rd... So that's my next project...But atleast now its driveable and reliable.
We still need install the shielding box, another set of valve covers and the correct orange cover hold downs but that stuff will come in a few weeks. Tomorrow it goes to the muffler shop to custom build some mandrel bent 2.5" side pipes with classic chambered 2.5" ID mufflers. Hopefully we'll get it all done in the next few weeks, just in time for the spring season.
Thanks for all of the help and ideas!!
I just finished up a TI system had an original distributor coil bought a new complete harness from M&H bought a solid state amp guts from Crane which was from M&H bought the coil from Paragon it was the only USA made TI coil I could find. I had heard or read on other blogs Camaros and such that the china made coils were causing problems. I just ran mine for the second time today with no problems with ignition. But now know that the carbs are the problem. good luck with you rebuild
I too have a 396 corvette in Milano Maroon. A transistorized ignition was mandatory correct? The guy that had it for awhile before me told me he had the dizzy rebuilt without points, or converted to solid state?. Would it still have a transistor? Does that just make for a hotter spark? I used to think that the transistorized ignition replaced the points all together.
Is it possible to bypass the transistor? Not that I want to, just not 100% sure it is still intact. What kind of special maintenance does it require? Away from the car at the moment, but trying to learn as much as I can in my free time. Thanks
Last edited by Austin Aubinoe; 02-13-2015 at 09:42 PM.
I too have a 396 corvette in Milano Maroon. A transistorized ignition was mandatory correct? The guy that had it for awhile before me told me he had the dizzy rebuilt without points, or converted to solid state?. Would it still have a transistor? Does that just make for a hotter spark? I used to think that the transistorized ignition replaced the points all together.
Is it possible to bypass the transistor? Not that I want to, just not 100% sure it is still intact. What kind of special maintenance does it require? Away from the car at the moment, but trying to learn as much as I can in my free time. Thanks
Yes K66 was mandatory with the solid lifter BB L78,L72,L71/L89 and L88's. And was a option on the rest except base engines. TI was GM first attempt at electronic ignition. It replaced the points
Glad you got it. NWMan nailed it in his first suspect culprit mentioning the coil.
Always goes to show that sometimes the "simple" things turn out to be the fault when we look at these somewhat complex ignitions.
Originally Posted by Austin Aubinoe
very good information in this thread!
I too have a 396 corvette in Milano Maroon. A transistorized ignition was mandatory correct? The guy that had it for awhile before me told me he had the dizzy rebuilt without points, or converted to solid state?. Would it still have a transistor? Does that just make for a hotter spark? I used to think that the transistorized ignition replaced the points all together.
Is it possible to bypass the transistor? Not that I want to, just not 100% sure it is still intact. What kind of special maintenance does it require? Away from the car at the moment, but trying to learn as much as I can in my free time. Thanks
Austin, I see you're a new member this month.....Welcome!
To know what is in your distributor and what system is installed, tell us what you have. You may have to look in the distributor to be sure. Is there a TI Module mounted on your radiator/core support right forward facing side? Are there 2 wires (white & white/green stripe) coming out of your distributor?
You say the prior owner had it ...."rebuilt without points". It is possible he installed a non-TI standard points distributor, then had it rebuilt later using a SS ignition system. If that was done, it could be one of several types of aftermarket ignition. The Pertronix is one. It would have 2 wires protruding from the distributor, one red, one black. Black to the coil-, red to the Ign +12v feed. There are other types...... some 3 wires, some one wire. Dave Fiedler has a comparison chart HERE.
The stock TI distributor does NOT include a "transistor". It includes a "pole piece", which is a powerful magnet and pickup coil assembly with the 2 wires terminating in a plastic plug. There is also a 8 position rotating stator and associated 8 position pickup ring which triggers the TI Module circuit via the pickup coil. (I may have the terminology wrong on some of the names of the internal parts, as I sometimes get them confused with my Jaguar OPUS(Oscillating Pick Up System) electronic ign dizzys) Those were prone to heat related issues as the amplifier was mounted deep in the "Vee" of the V12's directly BEHIND the stock GM A6 monster/hot air conditioning compressor. Ref pic HERE and HERE.
Thanks alot Rich! I really cant do anything with those pictures now, but I will refer back to them next time I am in front of the car. It runs friggen great right now, but I would like to make it as original as possible. I plan to bring it to Corvettes at Carlisle for its 50th birthday, so this summer I will make a thread with my concerns on fixing the little things.
I am hoping that its all stock, and the last owner just had modern electronics put into the old TI box. He did say they dizzy was quite complicated and expensive to have restored, which I now understand. Unfortunately, he did say he had to exchange the distributer. Where they date coded?
Thanks alot Rich! I really cant do anything with those pictures now, but I will refer back to them next time I am in front of the car. It runs friggen great right now, but I would like to make it as original as possible. I plan to bring it to Corvettes at Carlisle for its 50th birthday, so this summer I will make a thread with my concerns on fixing the little things.
I am hoping that its all stock, and the last owner just had modern electronics put into the old TI box. He did say they dizzy was quite complicated and expensive to have restored, which I now understand. Unfortunately, he did say he had to exchange the distributer. Where they date coded?
The distributer it self is not dated or marked anywhere on the housing. However there is a stamped steel band at the base that has a part number and a date on it. Bad news is they come off fairly easy and have been reproduced for years now.
Glad you got it. NWMan nailed it in his first suspect culprit mentioning the coil.
Always goes to show that sometimes the "simple" things turn out to be the fault when we look at these somewhat complex ignitions
Thanks!
Yes the coil swap solved the crazy idle fluctuations and dying. I'm still not 100% convinced the TI system is flawless yet though. I still have a high RPM misfire or breaking up I am working on diagnosing...also trying to verify its not a fuel supply problem. That's action item #1. The next issue is the secondaries are only opening about 25% on my brand new holley #3310 Vac secondary carb, even with a short yellow spring in it, so I'm working on that issue too.
We are sending the #3124 780 Holley carb we have to be restored/blueprinted and tested, I'm hoping that carb works a little better.
Steadily chasing gremlins out of this car but, it's like "whack a mole"...get one solved and two more arise. I'm on it though.
How are you monitoring the secondaries opening? I have used a zip tie, tied around secondary shaft on the driver side with a 2 inch tale sticking out from it. Rotate it as far forward as it will move - drive the car and see if it has reset about 90 deg indicating the secondaries opened up. just pointing out that something more than just winging the throttle in the driveway needs to be used for testing - which you probably already know.
A high rpm misfire could result if the distributor bushings have wear. Pretty easy to see on a dwell meter with points but other than feeling or measuring for excessive movement you might have to put it on a distributor machine to determine if it's a problem.
Last edited by DansYellow66; 02-16-2015 at 08:48 AM.
How are you monitoring the secondaries opening? I have used a zip tie, tied around secondary shaft on the driver side with a 2 inch tale sticking out from it. Rotate it as far forward as it will move - drive the car and see if it has reset about 90 deg indicating the secondaries opened up. just pointing out that something more than just winging the throttle in the driveway needs to be used for testing - which you probably already know.
A high rpm misfire could result if the distributor bushings have wear. Pretty easy to see on a dwell meter with points but other than feeling or measuring for excessive movement you might have to put it on a distributor machine to determine if it's a problem.
Yeah I put a tie wrap on the vac sec diaphragm shaft and as the secondaries open, it pushes the tie wrap down the shaft...Well, supposed to.. on mine it only pushes the tie wrap down about 1/4" or so down the shaft. That amount of travel yields about 25% of the secondary butterflies open. I've done the test twice. I checked the o ring, put the yellow spring in and verified the diaphragm works perfect when its not on the carb.
Next weekend, I am gonna throw an HEI in it for diagnostic testing to see if it will rev clean to redline, if it does, then I know the TI system has issues.
The #3124 carb went out today to be restored so it will end up back on there in a couple months but I still want to figure out why the 3310 isn't opening fully.
I know this thread is over 2 years old but having the EXACT symptoms you are with the same car, I think the repo coil also is the problem, curious to know if it was replaced in kind or with another manufacturer? Thanks
Something to keep in mind for TI wiring. For 64 and 65, the white resistor wire should be connected to the NEGATIVE - terminal of the ignition coil.
For 66-71, the white resistance wire should be connected to the POSTIVE + terminal of the ignition coil.
I'm not sure but I think the part number for the coil changed for 66.
Something to keep in mind for TI wiring. For 64 and 65, the white resistor wire should be connected to the NEGATIVE - terminal of the ignition coil.
For 66-71, the white resistance wire should be connected to the POSTIVE + terminal of the ignition coil.
I'm not sure but I think the part number for the coil changed for 66.
Just putting together my TI system now. Dave at TI will be doing the dizzy work. Planning on using the k&b amp. Whats the consensus on the best coil??
I know this thread is over 2 years old but having the EXACT symptoms you are with the same car, I think the repo coil also is the problem, curious to know if it was replaced in kind or with another manufacturer? Thanks
My dad ended up getting another Repro TI coil from a different vendor, I don't recall who it was, but definitely wasn't the same one as the other. I believe he bought that whole TI system new from some guy that specializes in TI... He spent a fortune on it. I personally think they are junk....We would get random high rpm misfires on the dyno and couldn't nail down what was causing it...On the street, I slapped an HEI in it for testing and it ran perfect, pulled clean to 6500.
Eventually we ended back up with running the TI system and the new coil, as well as the restored #3124 carb...All in all, the car runs pretty well. We havent driven it much in the last year as it has been down for paint, now its hitting the show circuit. I'm sure we'll drive it some this summer.
Short form of the story, if you are having a misfire/dying condition when hot, swap coils with a known good one. Just because they are new, doesn't mean they are good.
now its hitting the show circuit. I'm sure we'll drive it some this summer.
Just finished....
Before doing a lot of driving, I would switch the knock off adapters and spinners side for side. (if they're real knock offs) The lefts are on the right and the rights are on the left. They won't stay tight if installed that way.
Something to keep in mind for TI wiring. For 64 and 65, the white resistor wire should be connected to the NEGATIVE - terminal of the ignition coil.
For 66-71, the white resistance wire should be connected to the POSTIVE + terminal of the ignition coil.
I'm not sure but I think the part number for the coil changed for 66.
I was told the change was made to prevent the amp transistors from blowing out if the coil input wires were shorted out accidentally by the ignition shield.
how rare is it to have a magnet test good with an ohm meter (500-700 ohms) but be bad once it warms up? not having a distributor machine with a pulse adapter available I was told to put the magnet on a hot plate set at 150* and then do the ohm meter test? opinions please
how rare is it to have a magnet test good with an ohm meter (500-700 ohms) but be bad once it warms up? not having a distributor machine with a pulse adapter available I was told to put the magnet on a hot plate set at 150* and then do the ohm meter test? opinions please
I once had a similar issue. PU Coil reading within spec but intermittent trigger pulse. I pulled it apart and dissected the PU coil wiring.
The 2 wires are wrapped in white adhesive tape and soldered to the internal coil "micro"-wire. One of the connections was a cold solder joint. This was the problem causing the intermittent operation. In this case not heat because it failed cold, but likely vibration and high resistance. At the time I had no replacement so I repaired the PU coil and it's been in the car for the last 5 years running fine. A spare is in the car.
I suspect if you're reading at spec on yours cold, but fails hot, your coil has a similar issue with cold solder joint(s) on the lead wire(s), or internally the micro-wire has shorted to itself.
Before doing a lot of driving, I would switch the knock off adapters and spinners side for side. (if they're real knock offs) The lefts are on the right and the rights are on the left. They won't stay tight if installed that way.
Thanks!! Good to know... and good eyes... I'll mention it to my dad. They are real knock offs.
02-11-2015, 10:36 PM
) Those were prone to heat related issues as the amplifier was mounted deep in the "Vee" of the V12's directly BEHIND the stock GM A6 monster/hot air conditioning compressor.
Ref pic HERE and HERE.
