Question….owners of TI big block cars…..what replacement ignition coils are you using. I’ve upgraded the TI box guts to the newer solid state components if that makes any difference. Distributor and plug wires are OEM L71 components.

 

Found this post from @rich5962

Your Delco 207 is the best replacement coil for the L71. The 263 was the factory supplied coil and was never available in service as the 207 was the replacement which did in fact cover most TI applications. I would recommend you stay with what you have for reliability.

If you find a original stock Delco used 263 it will be expensive. If I were to find one I would want it tested under load and normalized temperature before purchase. A few years ago I tested 2 original 263's in a L71 for a friend after he paid $1k each. He was relieved that my tests passed.

Keep in mind that all reproduction TI coils available from the supplier in Georgia(China manufacturer) are internally identical. Only the debossed cases are different with the various 3 digit numbers to match factory supplied numbers. I would not recommend using any of the above reproduction coils for extended use as many have been reported to have had sporadic failures when temperature is normalized. I have direct experience. Internally a large percentage of these coils overheat and will leave you stranded. If the car is on and off a trailer for Flight/Bloomington judging you'll be fine, but not for Performance Verification as it could fail on the test ride under normal operating conditions..

I have done extensive testing on several reproduction 263's which I purchased as replacements and spares for several L71's. 2 of them reached over 250* F(IR gun at side and top of case) and failed under normal operating conditions on the road. Being stranded is not fun. After about 20 to 30 minutes cool down time it would recover and get us back to safety. In both cases they were installed inside the ignition distributor shield with a air gap at the bottom. I then experimented by removing them from the shield and strapped them outside the shield for better airflow. Both failed identically outside the "oven" reaching similar temperatures. Failures verified by replacing with a stock points coil(NAPA IC12).

Years ago Dave at TI Specialty gave me some advice. The IC12 coil will work fine for a TI system with a caveat being it will not supply the higher voltage to the TI circuit for high RPM performance. I ran one in a L71 for over a year, in the "oven" with no functional issues. The IC12 has a slightly larger diameter so it required a slight modification to the coil bracket to fit. I eventually replaced it with a NOS Delco 207 I bought, mounted back in the "oven", and it has performed flawlessly for the past 2 years.

I suspect that the reproductions primary coil shorts internally due to poor quality insulation of the heaver gauge primary coil wire along with the absence of quality control and/or proper testing at temperature. I suspect that if the manufacturer had proper testing and oven burn-in capabilities, they would likely report a 30 to 60 percent failure rate. I would imagine the only test they do is a static Primary and secondary ohms test and primary to secondary shorts test at ambient.

I have those failed reproduction coils sporadically placed on shelves in my shop displayed as "Garage Art". Some day I may open one up for visual inspection and some fault diagnosis, but then I'd loose my display fun.

Rich
PS BTW those repro coils are no longer being produced as allegedly the suppliers' China manufacturing facility had ceased operations. A shame.
​​​​​​​

 

Which module did you upgrade with and which coil are you using presently?

Rich

 

I’m using an original Echlin IC12 and the upgrade is in the TI amplifier box on the radiator support. Having an issue with the car shutting down and I’m suspicious of the coil overheating. I do have an original 207 coil but I suspect that gets cooked to. Gonna try running the car with the lid off of the coil box ignition shield.

 

Need more info to understand your issue. You say "shutting down". Exactly what happens, and how long after the engine is normalized?

Which module I asked about, meaning..... is it the K&B (green board) or the LL/M&H (epoxy filled)? I've only run a IC12 coil with the K&B version. Unsure about the LL/M&H version and it's reaction to the higher primary coil resistance.

K&B (Keep in mind the original screws in the Delco module setup are too long for this board and could cause intermittent faults. They bottom out. If you used this board, shorter mount screws are required and toothed lockwashers are recommended.


LL/M&H


What was in there before, the original Delco module?

Has this issue happened before the TI module upgrade?

When it shuts down, did you verify you have "no spark"?

Have you verified it's not a fuel issue? Vapor lock, etc?

Rich

 

This occurs after the engine reaches normal operating temp and is being driven for several miles. It’ll sit and idle perfectly all day though. Pretty sure it’s the epoxy filled amplifier aftermarket unit that’s installed. The car does have spark because I can fire it but it’ll sputter and die after a few seconds of either trying to idle or trying to drive, almost like it’s running out of fuel (but there’s a half tank). When this happens I do get strong jets of fuel into the center carb but I suppose that doesn’t indicate the absence of vapor lock. Correct vented cap on the tank too. A very good friend of mine who knows these cars inside & out is thinking it’s the coil getting too hot. I can say that when this occurs the coil is almost untouchable it’s that hot. So is the main coil wire. Not sure if running the car with the chrome ignition shielding (or maybe just without the chrome top cover) would help. I’m going to put another coil in (guessing another new Echlin IC12) and I’ll absolutely be sure to run the green circuit board replacement in the amp box. After that I’m stumped. Weak fuel pump (this original one was rebuilt by Fred in California when we built the engine). There’s a new gas tank in the car (my original with fully in tact tank sheet in safe storage). Or could it be the ignition switch going bad???

 

If you have spark after it dies, it's not Ign Switch, and since fuel is seen in carb after it dies it's not vapor lock.

It appears it may be the coil failing when heated, so easy to swap out and retry.

Some folks have had unusual cranking issues with the M&H (epoxy) module, where it'll only run after key is released from START. Problem clears after removing Solenoid R plug at TI harness distributor area.(Yellow and/or Pink wire). This never made sense to me but it hasn't ever been discussed or confirmed with the manufacturer.

I've had best results with K&B(green) modules, but availability may be a problem as the company changed owners years ago.

No need to get a K&B board if the present board is proven reliable.

But check all connectors and ensure your Grounds are clean & tight. The 3 prong TI Plug/Receptactle is a common issue too. Also check for wire integrity at the 2 pin distributor connector as its prone to fail also, either shorted to ground or intermittent opens. That is the Dist Pickup coil input/output.

Also ensure battery is in good condition and charging system is at spec. TI needs it more so than a points system.

Rich

 

I’m gonna get an IR temp gun. Any idea at what temp a coil will fail?

 

No idea but those repro 263's I had were over 250* when they failed.

There's no spec that has a maximum heat value on any coil I've seen.

I'd leave the shield cover off, run with existing coil, and tie-wrap a new IC12 near it, go run it until engine fails, then swap coil wiring to the new one strapped in and retry.

There are more structured ways to test the failure but youd need meters, tools, parts, and patience to diagnose a fault like this on the road. I've done that, but not fun in a busy area and 95* summer heat.

 

Yeah I’m at the point if I can’t enjoy this car I’m cashing it in while the market is hot. 67 L71 original yellow lacquer, sidepipes and 50k on the odometer. Cash out and move to Florida.

 

If the module in my car fails again, I'm going with a delco d1906 hei module and a normal coil.

 

I’d thought about doing the same…..just leave all the TI crap in place to make it appear stock.

 

Your issues sound very similar to what i was experiencing. my car would start great and run great cold, but if i parked it and it sat, hot restarts it would start like it had carb problems- chugging/stalling/gas smell. I'll spare you all the details and mistakes, but for me it was the pickup could in the dizzy. sadly for me it took until the car completely quit for me to find it.

you said you have a second coil and it gets hot too? having two coils that failed the same way seems a bit unlikely.

as to your question, i ran the Summit 850496 ignition coil on my TI setup with no issues.

 

Thanks TJ. Last night I came to the decision that I’m going to use a points disty and coil. I just don’t trust the TI system to be able to drive the car anywhere.

 

that is what i did. i even bought another TI distributor-i was going to swap all the TI stuff back in, but my car runs so good i dont see a need. what i would like to do if i ever had the time was build a fake TI setup that was just points, but looks liked all the TI stuff was there

 

Nice idea. I’m leaving all the visible TI stuff installed on the car for appearance sake.

 

Joe, you and ettev are ending up exactly where I did. '68 L71 roadster. It came with the TI stuff but was running a Mallory set up when I bought it. I had the TI dist rebuilt and properly curved, replaced the board, rebuilt the harness, etc. I don't have a coil I can trust so I decided to keep running what I've got because it works so well and you can't tell unless you remove the shield. I may switch at some point but, as the saying goes, 'if it ain't broke..........'.

'67 yellow L71! That could get me to sell a car and make room!

Best, Paul

 

Rich,
Is there a specific ground in the TI harness for the amp and where is it located? The internal board has a black, gray and pink wires from the harness. Is one of these wires ( black) also a case ground?

Am asking as I recently had a failure to start after the car (70 BB coupe with all factory parts) sat for 30 min after a drive. Once I got the car towed home, took my spare GM amp , plugged it in n then the engine fired right up. I had a jumper to ground the case to the frame. Noticed that when I removed the ground jumper the engine quit.

I purchased the green K&B updated board and installed it in the amp housing. Added a case ground to the amp engine fires up n runs fine.

The amp as u know, is mounted to the front side of the left front fender on fiberglass. So there is no case ground thru the fender. Am wondering why the amp ran flawlessly for 45 yrs with no external case ground n now needs one? If there is a ground in the TI harness, that may have failed in some way. If so, where do I look?

Thoughts?

Bob

 

^^^^ This video may help. It's for mid-late C2s with TI, but as I remember our '68 was the same as '67. I can go look later to see where it was grounded, but I think it's the same as this video shows for '67. I've also got a '68 wiring harness schematic. I'll go look for it (I knew exactly where it was before we moved. ) I'll also look in my AIM and NCRS book. Best, Paul

 

Paul,
The engine bay wiring schematic that is in the video shows the amplifier harness ( black wire) being grounded to the radiator support. I have not checked that harness ground on my car to see if that is the problem but probably is the culprit. I simply ran a separate ground wire back to the alternator ground and everything is running fine so far. Maybe my original harness ground to the radiator support has corrosion n is not supplying sufficient connection.
I installed the TI system on my car back in 74-75 using all factory parts. Purchased an extra amplifier, coil , n distributor at the same time so I do have GM spares of the critical parts. The TI harness in the car has not been replaced since it was installed new back in the day.
I did purchase n install the green K& B board in my amplifier. Didn’t do anything special with the screws that secure the board into the amp housing though. Hope that does not become a problem as the amp is not the easiest component to get to on the car.
The original system has been very reliable for 45+ years so I hope it continues to be a non issue in the car.
appreciate all ur help with the additional information.
Bob