Whats wrong with our ignition switches?, What do we know? Options

[JeffBowlsby]

"Ignition switches are junk"

Regularly hear this and similar consternation.

I have continuously owned one or more 914s since 1998...think I have replaced only 1 ignition switches over that time, in one car. My current primary car I have had for over twenty years, still on the original switch as far as I know, I have not replaced it during my ownership.

None my cars have ever had the added relay although I'm not against it.

For those switches removed and in other key ignition switches I have opened up, what I see is part of the housing is cracked in similar locations. Maybe from years of torquing the key over? Not sure. I don't see melted housings (believe they are nylon), no smoke residue or anything out of line, just the cracked housing. Suspect the cracked housing causes some internal misalignment of the internal contacts...i.e. the switch goes bad and needs replacement.

I am thinking the problem is the switch housings that break, not anything to do with excessive current flow through the switch.

Educate me please.

[wonkipop]

"Ignition switches are junk"

Regularly hear this and similar consternation.

I have continuously owned one or more 914s since 1998...think I have replaced only 1 ignition switches over that time, in one car. My current primary car I have had for over twenty years, still on the original switch as far as I know, I have not replaced it during my ownership.

None my cars have ever had the added relay although I'm not against it.

For those switches removed and in other key ignition switches I have opened up, what I see is part of the housing is cracked in similar locations. Maybe from years of torquing the key over? Not sure. I don't see melted housings (believe they are nylon), no smoke residue or anything out of line, just the cracked housing. Suspect the cracked housing causes some internal misalignment of the internal contacts...i.e. the switch goes bad and needs replacement.

I am thinking the problem is the switch housings that break, not anything to do with excessive current flow through the switch.

Educate me please.

apparently 911s suffer similarly. (same internals to ignition switch? dunno much about 911s in detail). i can ask mike#1 today when he comes in as he knows 911s in detail and i know the ignition switch had to be replaced on my mate's 76 911 a few years back.
it sounded like a similar problem to what happens to 914 switches you describe.

when it comes to plastic parts it is what happens.
gradual loss of plasticizers over time.
eventually the material becomes brittle.
just what happens to plastic.
hot UV exposure and climate temps accelerate the material decline.

[Root_Werks]

Similar here, replaced only one in a 914 over 35+ years. The plastic cracked and the switch made intermittent contact.

Heard the same from others, anything you can buy new is junk so to speak.

[wonkipop]

@JeffBowlsby

just asked mike#1.
911 switches probably not same he thinks but basically the plastic section held in by diecast wears and gets loose and the contacts inside no longer make proper connection.
its a wear issue in those switches rather than burning out due to excess current.
like a 914 big current goes through the switch.
common enough problem as the 911s of the that era got older.

[JeffBowlsby]

Without excessive current, then why the regular promotion of installing a relay? Does not seem to be necessary given the ampacity of the yellow wires involved. I never see the insulation on those wires cooked.

The main wire I see getting cooked is the black/purple tach wire on the ignition harnesses due to the mistake of reverse connecting to the coil with the black/red wire.

[Superhawk996]

Without excessive current, then why the regular promotion of installing a relay?

1) Mythology and superstition. Read it on the internet, a friend told me that’s the fix, or that’s what my daddy said, etc.

2) Desire for a quick fix when something goes wrong. Rather than fix underlying root cause like excessive voltage drop in the yellow solenoid circuit or a bad transmission ground strap, and even bad battery cables sometimes. The install of the second relay sounds like an appealing quick fix. It often works in the short term to band aid the symptoms but sometimes comes back with a vengeance because the root cause wasn’t addressed.

Actually it’s mostly #2 on cars I’ve fixed over the years but I added #1 to (IMG:style_emoticons/default/stirthepot.gif) (IMG:style_emoticons/default/laugh.gif)

[ctc911ctc]

I only have my personal experience

1970 1.7 - in very cold weather, the car would not start
replaced the Fuel Pump relay and then the ignition switch
Problem went away, but also the weather warmed up (IMG:style_emoticons/default/biggrin.gif)


1974 2.0 - in 1982 i was on Aviation Blvd and ElSegundo in LA, car stopped. Took it to the shop and the mechanic replaced the ignition switch which was brown on the inside.

1974 2.0 - recently, had intermitant problem, took a look at the ignition switch and it was burned up on the inside - replace with I believe a URO version?

Last time I bought one, I bought 2. (IMG:style_emoticons/default/smile.gif)

[ctc911ctc]

Just thinking outloud.... there is no current limiting circuits within any old analog cars. As a result if there is a manufacturing error or just sloppy percision, having a rotor that connects and then arcs can cause large instantaneous amounts of current. Not sure what the impulse current is on the Solinoid of the starter - this also can go out of spec and start drawing more current than designed.............. These small things, over time can erode the copper connections - dead spots etc.........



May have to think about this a bit -


(IMG:style_emoticons/default/dead horse.gif)

Without excessive current, then why the regular promotion of installing a relay? Does not seem to be necessary given the ampacity of the yellow wires involved. I never see the insulation on those wires cooked.

The main wire I see getting cooked is the black/purple tach wire on the ignition harnesses due to the mistake of reverse connecting to the coil with the black/red wire.

[bkrantz]

My car came with a relay added to the starter, a push button added under the dash, and a cracked ignition switch. During my rebuild, I removed all the extras, replaced the switch, and renewed some of the wiring. I have no problems with making the starter motor spin.

[Dlee6205]

Replacing ignition switches has become standard practice in my shop whether it “needs” (symptomatic) one or not. Everything gets a new switch. I don’t think I’ve pulled one out that wasn’t cracked. If it's cracked, it will fail eventually IMO. Here’s the latest example I pulled out a couple weeks ago that was failing to make contact. They’re 50 year old plastic components undergoing regular stresses, you cannot assume any of them are good anymore.





I don't understand adding the relay without first going through the basic steps and even the simple task of replacing the ignition switch. Every 914 I’ve seen with a relay has also had a crack ignition switch. I'm not completely against the relay but the right steps need to be taken first. Adding a relay without first replacing the ignition switch is asking for frustration.

[Superhawk996]

Well know fact . . . When it doesn’t start if you turn the key harder it helps. Probably explains more than a few cracked housings. (IMG:style_emoticons/default/laugh.gif)

I usually try to keep a few old German made switches around for troubleshooting

I have seen some minor arcing and pitting at the center contact (red) but none of them where inop due to arcing. This part was from a cracked housing.

I have also seen the center portion that actually engages the key / cylinder get worn out and enlarged resulting in the switch not turning in unison with the key. This causes intermittent contact issues and wonky starting. You can see the black center of the switch below getting wallowed out.

[Superhawk996]

Not sure what the impulse current is on the Solinoid of the starter - this also can go out of spec and start drawing more current than designed..............


May have to think about this a bit -

The OEM Bosch solenoid draws 25A. I’ve measured it on several starter solenoids using an accurate current shunt to make the measurement.



This goes back to the mythology. As circuits, wiring, and solenoids age, resistance increases, voltage drops increase. This decreases current draw.

Circuits don’t magically draw more current. Unless shorted and the smoke gets out but that is a whole different can of worms.

[davep]

It was about 1975 that I purchased a used 73 914. I have driven about 6 of them over the years. I think I have had to replace 3 switches. Yes, the plastic fails over time, that is a given; I won't go into details of why, but essentially it is just aging. The contacts themselves also age with time & use.
If a car is well cared for then it should start easily; essentially very quickly without undue cranking. If the car is hard to start, then a heavy current flows for much longer through the ignition switch, the wires and the interlock relay (if not bypassed) thus causing incremental damage. Every wire connection has resistance and the heavier the current the greater the heat in that connection. Over time that heat causes additional resistance in that connection.
Personally, I do not like the high current through the ignition switch; that is un-needed current through the power wires to the fuse panel, and then all the way back to the starter. It is always best to keep the high current wires short and heavy. And let us not forget the body that is the primary ground current carrier. I have had cars where the body was compromised and although the ground stud at the battery appeared solid, it would not carry the starter current adequately.
Well, yes there are current limiting circuits; that is the purpose of the fuse box. Some circuits are not fused however.
Also, a motor such as the starter will always present a short circuit to the battery (except for the resistance of the wires themselves) until the motor starts to turn. If you have ever tried to measure the starting current of a motor then you know it is essentially futile. Initially it is nearly infinite, but rapidly drops as the battery voltage falls and the starter rotor starts to turn. To measure the current you need a really fast digital storage scope.
My own personally constructed harness will utilize a relay near the starter to handle the solenoid current.

[Justinp71]

I added a relay because even after a new switch, occasionally the car would not want to start, never had the issue after installing the relay. Relay may be a Band-Aid but offers piece of mind in an otherwise difficult to diagnose situation (randomly not wanting to start leaving you stranded).

[bdstone914]

Not sure what the impulse current is on the Solinoid of the starter - this also can go out of spec and start drawing more current than designed..............


May have to think about this a bit -

The OEM Bosch solenoid draws 25A. I’ve measured it on several starter solenoids using an accurate current shunt to make the measurement.



This goes back to the mythology. As circuits, wiring, and solenoids age, resistance increases, voltage drops increase. This decreases current draw.

Circuits don’t magically draw more current. Unless shorted and the smoke gets out but that is a whole different can of worms.

If it draws 25 amps you don't tonk it needs a relay? I think most other parts like horns, fog lights, fuel pumps that draw less current are on relays. I dont think turning the switch harder causes the cracking. Is a weak design with a cast hole for the coil spring end leads to cracking. I once examined 10 used switches and 9 were cracked.
I believe in the relay.
I have not opened up any but I bet the contact get pitting that leads to excess heat and switch failure.
And most aftermarket switches seem to be junk.
I know someone who dropped a new one on the carpet of the car and it shattered.

[Superhawk996]

If it draws 25 amps you don't tonk it needs a relay? I think most other parts like horns, fog lights, fuel pumps that draw less current are on relays.

I dont think turning the switch harder causes the cracking.

On the first point - I don’t think it’s fair to judge vintage cars by modern standards.

Almost all cars of this vintage (both foreign and domestic) used high current switches for the starter and other things like headlamps, power windows, etc. The wiring and switch when new were sized appropriately to deal with the load. It’s the aging, voltage drops and the heat generated at high resistance junctions that are the root cause. I guess if we want to hold vintage cars to a modern standard we can say the high current switching is the root cause.

On the second point about turning the key harder I was being a smart ass. It is what people do but I agree with you that isn’t what leads to the ignition switch housing cranking that is very common. I do think it is part of what contributes to the center “key” portion getting wallowed out.

I’ve been around long enough to know that many people are still going to add the second relay. My main point is that it is unnecessary if the underlying system is sound (as designed) and that adding a second relay to control the first (ie the solenoid) is inelegant and is just another point of failure from a engineering Failure Mode Effects Analysis (FMEA) standpoint.

And on a side note about being stranded by a failure to crank. BS. You can slide under the tail end and use a screwdriver, a tire iron, or even spare change to short the solenoid terminal to the B+ terminal and the engine can be started. Not fun. But . . . I have been there, done that.

[GregAmy]

On the first point - I don’t think it’s fair to judge vintage cars by modern standards.

I agree.

But at the same time, I don't think it's fair to judge modern service and repair expectations by vintage design (unless you're shooting for Amelia center stage).

I stand by "it's your car, you should do with it what you want". But relaying a vintage starter solenoid when using a vintage starter switch is just good standard practice. And it's easy and cheap to do.

You can slide under the tail end and use a screwdriver, a tire iron, or even spare change to short the solenoid terminal to the B+ terminal and the engine can be started.

Ergo, your roadside repair is...relaying the solenoid.

(IMG:style_emoticons/default/wink.gif)

- GA

[Superhawk996]

Greg - You’re right about the roadside “relay”. (IMG:style_emoticons/default/lol-2.gif) (IMG:style_emoticons/default/smilie_pokal.gif)

I’m not disagreeing the second relay will help protect the ignition switch.

But here’s the issue . . . Far too often it is used to Band-Aid underlying issues like a failing transmission ground strap, battery cables in poor condition, or degradation of the yellow solenoid wiring.

Left unaddressed, those underlying issues get worse over time and eventually the secondary solenoid relay isn’t enough and they are left “stranded” yet again

[Dave97]

I have another problem I’ve been chasing. 1975 ign switch. The key/lock end that goes into the electrical part of the switch is worn. The key won’t turn the electrical part of the switch far enough to engage the start part of the switch because of the slop. In the beginning I thought is was the electrical part because everyone point to that, bought 3 of them. A new electrical part would work for a few months, but the plastic would wear just enough to not engage the starter.
The problem now is a finding a used lock assembly with a key. I’m going to try a vw lock assembly. I understand that I won’t be able to have the same key work the ign and other locks

[GregAmy]

Far too often it is used to Band-Aid underlying issues like a failing transmission ground strap, battery cables in poor condition, or degradation of the yellow solenoid wiring.

Completely agree! All that should be done as well, and at the same time (as well as a new switch). And if you don't do all that, even with the relay you'll still be unhappy.

The higher amperage through the switch probably contributes to its decay over time, but aging-based degradation made the problem obvious. And apparently most replacements are crap. - GA