Suspected TI issue - 1971 LT1 - original TI parts

[Patrick B.]

Re: Suspected TI issue - 1971 LT1 - original TI parts

It is good to know that Dave Fiedler had never seen TI problems with solid wires himself and was relating the impressions of others who were not experts. Since we now know that a lot of timing lights are affected by EMI, I think there is a likelihood that erratic timing light operation contributed to the impression of erratic TI performance.

[James G.]

Re: Suspected TI issue - 1971 LT1 - original TI parts

I believe it was a ground issue, when I got to inspecting after I dry ice cleaned the the area, the 3 bolts were all loose and after cleaning and tightening everything it has fired up easily and doesn't appear to have the erratic skip either. I have the amp board in the rear tray, if I need it.

I hope it was that simple...

[Duke W.]

Re: Suspected TI issue - 1971 LT1 - original TI parts

Isn't there a dedicated ground wire that should tie to the radiator support? On a C2 the amp is mounted to the fiberglass inner fender panel, so the housing itself is not grounded. That's the reason for the dedicated ground wire.

Are C3s different?

Duke

[Richard M.]

Re: Suspected TI issue - 1971 LT1 - original TI parts

Isn't there a dedicated ground wire that should tie to the radiator support? On a C2 the amp is mounted to the fiberglass inner fender panel, so the housing itself is not grounded. That's the reason for the dedicated ground wire.

Are C3s different?

Duke

Duke, Yes there is a dedicated ground wire that attaches to the Core Support, all the way in the TI harness to the Coil- terminal. But it is attached to the AMP with one of the 3 mount bolts that attach the AMP to the fiberglass skirt on the C3's.

A loose attachment bolt there means the AMP had a intermittent ground.

Rich
P.S. Post#10, Paragraph 2

[James G.]

Re: Suspected TI issue - 1971 LT1 - original TI parts

Yes, Rich exactly, there is a metal strap off the bottom of the amplifier, visible under the lower right mount on the amp.

Which when looking here is still corroded, I should probably go in and really clean the ground.
TI_AMP_AFTER2.jpg

[Patrick B.]

[Richard M.]

Re: Suspected TI issue - 1971 LT1 - original TI parts

James, I think this is what that clip looks like. I believe it began use in 1968. It attaches to one of the cover screws and the big hole is for the 1/4-20 mount bolt. I suggest a good cleaning and use a toothed lock washer between the case and the ground terminal.

20231130_112911.jpg

20231130_112958.jpg

[Richard M.]

Re: Suspected TI issue - 1971 LT1 - original TI parts

James, I just noticed something. Your ground wire is on the bolt shown at left in your photo. That clip on the right bolt is not really needed. The ground for the AMP comes directly from the Core Support, and also through the harness to Coil-.

I could certainly be wrong, but I believe the clip was used to create a proper ground on Passenger cars of the era. On those the mount point is grounded and the "teeth" on that clip would scratch the paint and provide a good connection to sheet metal.

TI_AMP_AFTER2_Mod.jpg

[James G.]

Re: Suspected TI issue - 1971 LT1 - original TI parts

You are 100% correct,
All 3 bolts were loose so I am sure that tightening the one with the wire is what remedied the issue.
I am going to make sure there are no white aluminum oxide crystals anywhere near the grounding ring, then I will put some NOALOX on it -
NOALOX is a electrical joint compound for bimetallic connections which serves to prevent galvanic corrosion and ensure a good electrical connection.
100_9577.jpg

I have been using this stuff for 15 years or so and have not had issues with grounds or harnesses since I began using it.
Whether that is because I am more meticulous with the harness plugs and grounding rings OR whether it actually increases continuity I cannot definitively state. After brushing a little bit on a harness plug or grounding ring. With a new harness I just plug together - AN ORIGINAL HARNESS - plug - unplug - plug - unplug - plug- so the paste works the connection and polishes the spade or the grounding ring.

Last I bought, from Lowes or Home Depot - IIRC The bottle above I got at Wal Mart ~ $10-15

[Keith W.]

Re: Suspected TI issue - 1971 LT1 - original TI parts

James, is the NOALOX a black compound and would the appearance hurt for judging?

[Richard M.]

Re: Suspected TI issue - 1971 LT1 - original TI parts

You are 100% correct,
All 3 bolts were loose so I am sure that tightening the one with the wire is what remedied the issue.
I am going to make sure there are no white aluminum oxide crystals anywhere near the grounding ring, then I will put some NOALOX on it -
.
.
.

James,

I recommend that you remove the AMP and clean the mount boss for the ground wire, as well as cleaning the terminal on both sides. Ensure that the copper wire is not corroded at the crimp. If it is, cut it and clean the wire to bare copper. Using a soldering gun, reattach the wire to the terminal, or replace with new, after adding a piece of heat shrink to the wire. After the new connection is soldered apply the heat shrink.

Then add a toothed lockwasher between the terminal and AMP mount boss. Then apply the Noalox around the periphery of the connection to insulate it from corrosion.

Then go to the core support ground terminal connection. Repeat the above process.

I'd have confidence that you'd never have a intermittent AMP ground fault until the moon collapses.

Rich

[James G.]

Re: Suspected TI issue - 1971 LT1 - original TI parts

Rich exactly what I have planned.

Keith,
It is a translucent gray color and doesn't stick out or draw a red flag.