Ignition Switch, 83 SC

TLutes · 03-11-2015, 03:48 PM

I have just finished reading several threads re faulty ignition switches with excellent advice from folks like brads911sc, ossiblue, armand80sc and more for my 83 SC. I am looking for confirmation of isolating the problem before I go purchase the electrical portion of the ignition switch (about $114.). I got in the car turned the key, it started cranking then backfired thru the air box (yes there is a pop off valve installed). I rotated the key back to the off position and tried again. There was no spring like resistance when I came to the "Start" position, it just started cranking. It tried to catch so I tapped the accelerator but no luck. I could smell gas. I turned the key back to the off position and guess what. It continued to crank! I wiggled the key and it stopped. Even when I took my hand off the key when it was in the start position, it did not spring back and stop cranking. That's when I started reading threads. The key turns easily in both directions so I don't think it is the mechanical side ($$$$$) of the assembly. It looks like the ignition switch has been replaced before as what I think where two rivets have been drilled out and not replaced from the cabin side of the car. The two breakoff bolts are there.
Can anyone confirm it is the electrical switch? Thx

RSTarga · 03-11-2015, 04:09 PM

Take the whole assembly out to diagnose. Pretty sure the spring return is in the mechanical portion.

pete3799 · pete3799's Garage

Spring is in the electrical side of the switch. Sounds like you need a new one to me.

ossiblue · 03-11-2015, 05:04 PM

Quote:

Originally Posted by pete3799

Spring is in the electrical side of the switch. Sounds like you need a new one to me.

Yes, this^^.

You can replace the electrical part without removing the mechanical portion, but it is a royal PITA. Removing the entire switch will allow easy r/r of the electrical part and you can replace the shear bolts with Allen head bolts, if you wish.

SpyderMike · 03-11-2015, 07:50 PM

I pulled my electrical switch mechanism without much trouble. What made it a PITA for you?

Coastr · 03-11-2015, 08:38 PM

Pull the entire assembly. You need a short allen key to get the steering bolt grub screw out a few turns and there isn't much clearance.

Pull out the lock and leave the switch in the car (connected to loom). Try the action of the switch with a screwdriver.

I just went through this (and unncessiraly bought a new switch).

There is spring action in the switch - but it's not a lot. The replacement part i got was a 964 numbered part, and the lockout is in the switch, but the original SC part the lockout is in the lock. By lockout I mean you have to turn the key back to '12' before you can engage the starter again.

I determined how far you have to turn the switch to get to the spring. If you start at 12 o'clock on the switch, the starter spring is about 7 o'clock. The spring only goes to about 7:05 (i.e., a very small amount).

If you're luck there is nothing wrong. If you are unlucky you have play in your lock because the lock is $1000 or find a used one, all of which are priced at $300 or more.

But your first move is lock/switch assembly removal. You need to get out the break off bolts and loosen the steering column lock nut and grub screw and do some wiggling.

ossiblue · 03-12-2015, 07:57 AM

Quote:

Originally Posted by SpyderMike

I pulled my electrical switch mechanism without much trouble. What made it a PITA for you?

Old guy. On his back. Head under dash. Hard to see. Bump in floor pressing into spine. Un-seeable, small top screw on switch part. Need for extra short screw driver....and more.

SpyderMike · 03-12-2015, 01:23 PM

Quote:

Originally Posted by ossiblue

Old guy. On his back. Head under dash. Hard to see. Bump in floor pressing into spine. Un-seeable, small top screw on switch part. Need for extra short screw driver....and more.

got it! Thanks

spuggy · 03-13-2015, 07:35 AM

Quote:

Originally Posted by Coastr

There is spring action in the switch - but it's not a lot. The replacement part i got was a 964 numbered part, and the lockout is in the switch, but the original SC part the lockout is in the lock. By lockout I mean you have to turn the key back to '12' before you can engage the starter again.

I never even realized there was a lockout mechanism, until I fitted the 964 electrical portion trying to isolate a start problem - and the lockout really bugged me...

The earlier electrical switches (still listed last I checked, but twice the price of the 964 part) don't have the lockout in the electrical portion. I have a spare '86 930 electrical portion - that doesn't have the lockout either...

I have a spare lock assembly (probably an earlier car) and my original '77 one - neither have a lockout in the lock itself (e.g. remove the electrical portion, the key just spins freely).

But your SC lock assembly has a mech lockout? What year is that?

TLutes · 03-13-2015, 11:59 AM

After being ill all week I am finally able to tackle this. Lots and lots of advice on the threads! One piece of advice was to take a Dremel and cut a slot in top of the break off bolts and then use a slot screwdriver to back them out. Finally tracking down a Dremel EZ lock mandrel and EZ lock metal cutoff wheel, I tried it only to find out the body of the mandrel interfered with the key tumbler assembly before the wheel came in contact with the break off bolt.

So I guess I will drill out the bolt. Question is what size drill bit do I use to do that? How deep do I drill into the bolt?

Thx
Tracy

jlynch1960 · jlynch1960's Garage

What is the consensus on the lock-out feature? If I get a no start, I have to return the key to 12 o'clock to give it another go. I replaced the electrical switch a couple of years back but had the same result with both switches. I don't think the lock assembly was changed for decades. Kind of an annoying feature. Not to highjack, but seems and appropriate thread to bring it up since several have mentioned it.

pete3799 · pete3799's Garage

the lock out feature on my 79sc is in the lock (mechanical) part of the switch. On the back side of the tumbler.

To get the break off bolts out I used a punch with a sharp point. Put a dimple on the outer edge of the bolt head then angle the punch and tap it counter clockwise.

TLutes · 03-21-2015, 02:56 PM

Thanks for the tips. I tried using the sharp punch trick on the break off bolts but they were really in there. I finally took a very small cone shaped Dremel grinding "bit" and created a flat spot that allowed me to take a 5/64th in. drill bit and drill a hole about 1/8th in. deep. Using a punch, I was then able to move the bolt around. I did this three time until on the third hole I was able to stick the tips of a needle nose plier in two opposing holes and back the bolt out. Even with the steering wheel out there is not a lot of room to work. PITA.

Unplugging the harness, loosening the nut holding the anti theft device to the steering wheel went smoothly. The trick to getting the assembly out is to rotate it down and back once the lock clears the dash hole.

After separating the wire harness from electrical switch by removing the two Phillips screws, I used a slot screw driver to turn the switch (+). It cranked and almost caught but did not start. There was no spring back action when I took the screw driver out so I ordered a new electrical switch from our host, stuck it in and got the same results!!! PITA. The new switch does have some spring back, not much, but even after letting it crank and then removing the screw driver it did not stop cranking and I had to rotate it to off to get it to stop cranking.

I even tried bolting the electrical switch back onto the the mechanical side with the key. No joy of course. While I have it out should take the tumblers out? BTW tabs are good on the mechanical side.

Anybody got any ideas as to why its not starting and the new switch did not do the trick?

TLutes · 05-07-2015, 07:22 PM

I finished this project up about a month ago and thought I would give some feedback. As I stated previously, the new 964 electrical side of the switch was installed and did not solve the problem. I started to take the tumblers out, thought better of it and took the whole assembly to my mechanic Neal Appel who confirmed it was the issue. The key would drag when turned enough to inhibit the spring back action of the electrical switch. Neal had a used set of tumblers, rekeyed them and the problem was solved. You will recall when this all started the car backfired when I tried to start it. Neal had me check the air box saying that sometimes the air box cover is displaced with a backfire. Pulling the top of the airbox off and removing the filter I found the popoff valve almost completely out of its hole. The epoxy did not hold it in! I cleaned it up and re epoxed it. Works and runs great. Neal's advice was spot on. The name of Neal's shop is LDM Inc. He only works Porsche's up through 1989.