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#51

Technical / Authenticity / Re: 1956 Ignition switch smoki...

Last post by TJ Hopland - September 01, 2025, 09:50:02 PM

Did it look like that area was rubbing on something?  or just touching another wire that got even hotter and melted into that one?  You normally don't see a wire fail midway. 

#52

Technical / Authenticity / Re: 1956 Ignition switch smoki...

Last post by 56Fleetwood - September 01, 2025, 09:34:49 PM

Was able to get the ignition switch apart from the bezel. Examined the wiring and found the pink IGN wire has insulation scorched and melted (see pic). I'll probably repair this with a Permatex liquid electrical tape product as I can't reach it with heat shrink tubing.

Hoping this is the only cause of the smoking etc. Any comments/suggestions appreciated.

#53

Technical / Authenticity / Re: 1960 Hydramatic...What's i...

Last post by The Tassie Devil(le) - September 01, 2025, 07:16:20 PM

I probably wouldn't go to the 10spd but the 6l80e and 8L90 are great (in my experience).  All that is just conjecture at this point, anyway. This car runs great and it appears that it may be shifting as designed (the purpose of this thread was to help me determine that).

Good choice.

The trouble with too many gears is that these transmissions are designed for engines with a very narrow torque band, and require so many gears to get any sort of performance and meet strict anti-pollution requirements.   The top couple of gears are simply added overdrive gears.

Bruce.

#54

Technical / Authenticity / 1970sPower servo rotary valve

Last post by rms70 - September 01, 2025, 04:54:39 PM

Been working on the climate control to get at least heat into cabin.(hasn't worked since restarted car in 2020 after 20plus years in storage). This led to an engine and radiator flush, new heater core,new hoses,new water control valve and buying Cadillac Tim's book. The book is great, really makes the complicated system understandable. Worked on in dash unit first and found rotary valve grooves filled with metallic dust. I reconditioned the valve according to the book directions but couldn't get it to stop leaking vacuum. I blamed it on the rectangular retaining spring that holds the two halves together which I deformed when I took the halves apart. Tim  sold me a dash valve he had reconditioned and after the struggle of putting everything back together the dash unit now sends a solid 17 inches of vacuum to the system. The vacuum feed up to the power servo  is the same 17 inches to port four but when calling for heat(rotary valve rotated by the diaphragm pulling arm in) there is no vacuum at port 2 which would open the water control valve. This rotary valve must be really warped because I've tried sanding it and leveling it a half dozen times to no avail( or  no vacuum). I'm beginning to think my fail on the in dash valve might not just have been the retaining spring. Has anyone reconditioned their valve by Cadillac Tim's method and gotten it to work? As a side note, I called Eldorado George to get some advice. He won't work on just my valve but would restore the entire servo unit, beautiful job but pricey. He also said the two valve sides must be perfect,he grinds them in a 50 thousand grit slurry and when put together dry they can't be pulled apart. When I dismantled the engine back in 1998 I remember the climate control system working, cold air and heat. I can't imagine the two valve halves were in a perfect  condition after 28 years. Anyway, if anyone has reconditioned their rotary valve how did you do it?  How did you get it flat and how did you know it was good before reinstalling it? Mine now look flat,no visible high spots or low areas but still no vacuum. If all else fails maybe Cadillac Tim has one for sale..need to do something before those nice day cold weather drives.
              Thanks,
                   Rob

#55

Technical / Authenticity / Re: 1956 Ignition switch smoki...

Last post by 56Fleetwood - September 01, 2025, 03:58:31 PM

Thanks. Will do as suggested and report back with my findings

#56

Technical / Authenticity / Re: 1956 Ignition switch smoki...

Last post by J. Gomez - September 01, 2025, 03:46:24 PM

Thanks for this TJ. I'm hoping your suggestion of mechanical failure of the switch is correct. First things first, I'll remove the switch and test it.

The shop manual doesn't have any description of switch removal from what I can see. I assume the chrome bezel comes off first, so does the ignition switch just loosen up for removal after that?

Mike

MB,

Yes, you just need to unscrew the front bezel to remove the switch. If you do not have the tool you can use a needle nose BUT it is a PITA and you will scratch it, just be prepared.

#57

Technical / Authenticity / Re: 1956 Ignition switch smoki...

Last post by J. Gomez - September 01, 2025, 03:42:40 PM

Problem with my ignition switch; started the engine with no problem but then got smoke coming from the ignition switch with a simultaneous grinding noise from under the hood. I shut it off immediately but still got smoke from ignition switch (disconnected battery immediately).

Where do I start diagnosing this problem?

MB,

Assuming the smoke came from a wire(s) insulator at the Ign. switch best option is to find out which one.
The Ign. switch feeds several others when it is moved to start the engine (SOL purple wire to the neutral switch) and released after (IGN pink wire to several fuses and other location) position.

If it happens during cranking I would start with inspecting and disconnecting the purple wire and checking for short.

If it happens after the engine started I would start with the pink wire and check for shorts by removing fuses (one at a time) and tracing other path that feeds from the same source.

Good luck..! 

#58

Technical / Authenticity / Re: 1956 Ignition switch smoki...

Last post by 56Fleetwood - September 01, 2025, 03:42:00 PM

Thanks for this TJ. I'm hoping your suggestion of mechanical failure of the switch is correct. First things first, I'll remove the switch and test it.

The shop manual doesn't have any description of switch removal from what I can see. I assume the chrome bezel comes off first, so does the ignition switch just loosen up for removal after that?

Mike

#59

Technical / Authenticity / Re: 1956 Ignition switch smoki...

Last post by TJ Hopland - September 01, 2025, 03:23:25 PM

I'm gonna guess that something failed in the switch leaving the starter engaged.  Failure could have been a simple mechanical failure where a contact came loose and stayed making contact for the starting circuit. 

I wonder if the starter actually stayed engaged like literally now being spun by engine thus making it into a generator (with no regulation)?   Or did it momentary drop out before the switch failed so it did disengage from the engine but then got re energized and was just grinding? At that point its not a generator so was the smoke just from how or where the switch failed perhaps shorting something to the body which I assume is metal and bolted into a metal dash so grounded? 

I don't know a 56 but I would say start with getting the the switch out so you can get a look at it.  I don't know if this means the whole lock and all or if just the electrical section comes off.  Seeing what the damage is and maybe using an ohm meter to see what pin(s) were involved may give you some clues as to what other parts of the system need to be investigated.

If it was mine I think I would want to get a look at the starter and ring gear too.  Not sure if there is an inspection cover or if you would have to pull the starter.  Verify that that was where the noise was coming from (should be obvious) and how bad the damage is.   If nothing looks like it was rubbing there then guess you have to take the belts off and spin things by hand to see what failed like maybe the generator?  Some odd failure that sent electrical spikes and cooked the switch? 

#60

Technical / Authenticity / 1950s1956 Ignition switch smoking

Last post by 56Fleetwood - September 01, 2025, 02:12:38 PM

Problem with my ignition switch; started the engine with no problem but then got smoke coming from the ignition switch with a simultaneous grinding noise from under the hood. I shut it off immediately but still got smoke from ignition switch (disconnected battery immediately).

Where do I start diagnosing this problem?