67 Signal Switch-Problems Again

[Gerard F.]

This time with the horn contact.

About 4-5 years ago I was having problems with my original 67 signal switch and I went through 3 replacement switches before I thought I got the correct USA made switch. This switch is particular only to 67 and 68 Corvettes and is known as the Boyne switch. I did a lot of posts in 2008-2009 on my trials and tribulations with the Boyne switch in the 67-68 steering column. I have yet to write a Restorer story on the switch. It is just a time thing with so much else to do with the Corvette.

But, about 4 1/2 years ago, I thought I found a correct USA made 67 signal switch and put it on for the San Jose Convention for Founders Ops and it work perfectly. For the signal, hazard and brake functions it has work perfectly and still does after 4 1/2 years and a little over 5000 miles to events and around town in my 67. But a couple of months ago my horns started to act erratic and then finally a couple of weeks ago the horns just stopped working.

I figured it was something in the horns or the horn relay or the front harness, and spent a lot of time troubleshooting those items and traced it back to signal switch. I found that the easy test of the whole front end horn system is to simply ground the black wire at the harness connector under the dash from the steering column to the front harness. You don't even need to disconnect the harness connector from the steering column connector. Just insert a wire probe into the connector from the steering column side and then ground that probe. If the horn blows, everything up front in the horn system is OK. I did this isolated the problem to the signal switch or upper steering wheel column.

I really didn't want to have to do it but then I pulled the horn button assembly, the steering wheel, and the cancelling cam (which contacts the horn contact) in the steering column. This is what I found:



Just notice the copper colored dust over the plastic shield over the signal switch and at the bottom of the column enclosure, and the depth of the horn contact above the plastic shield.



In removing the shield here is photo of the switch. Take a look at the copper horn contact and the distance that it extends from switch enclosure. I just can't believe that the horn contact was worn as bad in 4 1/2 years and 5000 miles.
The original switch lasted 38 years and at least 60 k miles and doesn't show the wear that this replacement does. Here's what the depth of the horn contact should look like on the replacement switch I just put on . Everything including the horn now works perfectly:



Notice the length of that horn contact. I just can believe that something would wear so shortly with a reproduction. Is there something in the copper contacts that they use now, or have I installed something incorrectly. I just can't believe this.
Let me know if you have some other ideas on this.

But my moral of the story is that if your having problems with your horns on a 67 (or 68) with a replacement signal switch, check the signal switch first.
Anybody got some other explanation of the wear on the horn contact.

But still having fun And I'll write that Restorer story some day.

[Timothy B.]

Re: 67 Signal Switch-Problems Again

Jerry,

With all the problems you have had with this switch keep a eye for a NOS part and if one comes available buy and install it.

I remember this switch broke in my 67 and back in the late eighties waiting for some time for the GM part to arrive, I also have seen them on the internet so be patient. I can't begin to offer an explanation why this copper contact is wore like that it just seems like all reproductions parts are problematic.

[Stephen L.]

Re: 67 Signal Switch-Problems Again

Jerry, it appears that the spring pressure was extreme or the copper post is soft compared to the original. If you have the old switch, replace the copper pin with the original pin. If not then fabricate a new pin from a brass rod. Could you have assembled the parts incorrectly 4 yrs ago causing excessive spring pressure. What damage is there on the slip ring that the copper post rides against? The other thing you could do is always drive in a straight line avoiding rotating the steering wheel..... LOL.

[Joe C.]

Re: 67 Signal Switch-Problems Again

Hi Jerry,

I can't explain it, but can draw a parallel to a similar nagging problem that I've been having with distributor lower main shaft bushings. This last one only lasted less than 7000 miles, and took out the shaft with it. I only found it because the timing had moved unexpectedly. This time I installed an upper bushing in the lower position and reamed it for .004" clearance, polished the new shaft, and drilled a pressure oiling hole for it.

Might be differing materials, spring pressure, or lack of lubrication. Good luck finding the problem

[Gene M.]

Re: 67 Signal Switch-Problems Again

Joe,
Some oil lite materials do not wear well with steels that have a high nickel content. Stainless steels are real bad for this.

Would not a ball bearing distributor be a better choice? Assuming this is on your built up small block........

[Gerard F.]

Re: 67 Signal Switch-Problems Again

Steve, Joe

I think I figured it out. The horn contact on the repro seems (by the touch) to have a little higher spring compression, than the original (which I still have). The original contact seems to be more gentle to the touch in compression.
But to say for sure, I'll have to scientifically test them with some fishing weights.

The original cancelling cam at the bottom of the picture below shows some wear where it touches the horn contact but no real damage. I remember when I put the repro on, I noticed a slight rubbing noise as the wheel turned. Some of that conductive lub would probably help the wear also.



Here's another question for anyone.

The GM replacement cancelling cam at the top of the picture above has two bumps or cams on the back versus the only one on the original. Does this have any effect on the turn signal cancelling, or is this just a generic replacement thing for use on other GM vehicles?

Having fun,

[Stephen L.]

Re: 67 Signal Switch-Problems Again

The additional cam could cause the "cancel" to happen a little sooner in the rotation of the steering wheel.... probably patterned after a later GM revision.

[Gene M.]

Re: 67 Signal Switch-Problems Again

The additional cam could cause the "cancel" to happen a little sooner in the rotation of the steering wheel.... probably patterned after a later GM revision.

Good grief, another thing for the PV judge...................!

[Joe C.]

Re: 67 Signal Switch-Problems Again

Joe,
Some oil lite materials do not wear well with steels that have a high nickel content. Stainless steels are real bad for this.

Would not a ball bearing distributor be a better choice? Assuming this is on your built up small block........

Thanks Gene. Yes, its for the built up smallblock. It is not an oillite bushing. It's a bronze UPPER bushing from LICS, so it's now 2x as long as the original lower bushing, which is one of the tricks that the better known rebuilders use. I have a lot of time and effort invested in the original distributor, and it works so well (except for the lower bushing) that it seems a damn shame to give up on it now. I'd rather try to understand the problem and fix it, rather than buying an expensive aftermarket unit. Of course, the desire to keep this motor stock looking (except for the headers) continues, and that includes keeping the ignition shielding as well.

Eventually the Accel, Pertronix, Mallory or MSD distributor might be a possibility, but not until if and when I finally send it to Dave Fiedler if this bushing fails.

[Gene M.]

Re: 67 Signal Switch-Problems Again

Joe,
Is it possible the helical gears are transferring a greater tangential loads to the distributor shaft due to a camshaft load being higher because of steeper ramps and stiffer springs? A longer lower bearing will help spread the side load out. I suggest this because the only side load on the lower bearing is the gear set. The oil pump is pure rotational. Alignment of distributor shaft is determined by the intake manifold hole position.

Knowing you, you will figure out the solution.

[Joe C.]

Re: 67 Signal Switch-Problems Again

Joe,
Is it possible the helical gears are transferring a greater tangential loads to the distributor shaft due to a camshaft load being higher because of steeper ramps and stiffer springs? A longer lower bearing will help spread the side load out. I suggest this because the only side load on the lower bearing is the gear set. The oil pump is pure rotational. Alignment of distributor shaft is determined by the intake manifold hole position.

Knowing you, you will figure out the solution.

Gene,

I moved this to a different thread.

https://www.forums.ncrs.org/showthre...182#post686182

[Gerard F.]

Re: 67 Signal Switch-Problems Again

Hi Jerry,

I can't explain it, but can draw a parallel to a similar nagging problem that I've been having with distributor lower main shaft bushings. This last one only lasted less than 7000 miles, and took out the shaft with it. I only found it because the timing had moved unexpectedly. This time I installed an upper bushing in the lower position and reamed it for .004" clearance, polished the new shaft, and drilled a pressure oiling hole for it.

Might be differing materials, spring pressure, or lack of lubrication. Good luck finding the problem

Joe,

I figured it out- see this thread:

https://www.forums.ncrs.org/showthre...-Horn-Problems

The problem was a badly worn original cancelling cam and improper (round headed) signal lever screw. The worn plastic bearing end of the cancelling cam and interference of the signal lever screw put more pressure on the copper signal switch contact and just wore it down.

[Joe C.]

Re: 67 Signal Switch-Problems Again

Joe,

I figured it out- see this thread:

https://www.forums.ncrs.org/showthre...-Horn-Problems

The problem was a badly worn original cancelling cam and improper (round headed) signal lever screw. The worn plastic bearing end of the cancelling cam and interference of the signal lever screw put more pressure on the copper signal switch contact and just wore it down.

Nice!
Use hand signals.