Noticed some odd keying for the Z I'm working on ('71). Another car's ignition key being keyed to the glovebox and—

Anyway: I turned the ignition with the wrong key (WK), it got stuck 180° clockwise (in the on position) and won't turn back with the WK. This WK turned smooth into the on position and got entirely stuck. The right key also has resistance going in and I don't want to break anything further.

I already have a work around, but is there any way to keep the ignition and fix this?
Also why does it allow the wrong key, turn, then lock up?

Edited July 28Jul 28 by RobotandtheRoad
Appended question

It all has to do with the way the lock mechanism wears. And it often wears in such a way that a key can get stuck in the lock.

As far as getting the stuck key out, I'm thinking that with enough effort and finesse, you might be able to coax the WK back out. I'm thinking that with very gentle pressure while at the same time a couple hard raps on a hard surface (in the proper direction) might be able to move the tumblers inside enough to get the WK out?

But honestly, if the lock is that badly worn, it's probably time to replace it anyway.

Initially got the key out with a little bit of tugging.
I was able to take the lock to a locksmith and get the cylinder unstuck. From what I understand, it will admit any wrong key and turn as long as a specific cut matches. Then it breaks or gets stuck after turning to a certain point. A little frustrating on a car with 3 different keys.

Edited August 1Aug 1 by RobotandtheRoad
Clarification

10 hours ago, RobotandtheRoad said:

From what I understand, it will admit any wrong key and turn as long as a specific cut matches. Then it breaks or gets stuck after turning to a certain point. A little frustrating on a car with 3 different keys.

What you understand, unfortunately, is not correct. The wrong key should never be able to turn.

If it is the correct key blank for that cylinder, it should insert just fine. But if it's not profiled to match the wafers (tumblers) in said cylinder, it should not turn. And if it does, it's because the lock is worn and should probably be replaced.

When these ignition locks get worn they can go bad in a multitude of ways. One of the ways is they can accept the wrong key as long as it's the correct keyway and they will go to the running position and freeze in that position like what happened to you. It's good that you managed to get the key out, I can usually do that with the lock in my hand but it takes a little finesse. This scenario of the lock getting stuck in the running position is not that uncommon considering how old these cars are getting. Another rule of thumb on these locks is if you can pull the key out with the car running the lock needs to be rebuilt. On the dual sided key style of ignition switch which ran from 1972 all the way through the 1983 year they are rebuildable and I can do that. I can recode them as needed and if needed and I've been doing locks for z cars since about 1997. The only issue I'm running into is the lock parts are getting scarce and so is finding someone that knows what parts they have. I carry most lock parts in stock. I can rebuild the ignition locks and the door locks on all the dual sided keys. All the cars from 1972-1983 use one key fits all the locks. I can recode most locks to accept a specific key. There are 2 styles of keyways, the X6 and the X7, their mirror'd images of each other. I can do either one. For the hatch locks I can't rebuild them but I can put new wafers in to get them working better. Other than that no parts are available for the hatch locks. I'm now in my 48th year of repairing and resurrecting z cars. Contact me by e-mail or by phone for more information. The Z Whisperer

zmanofwashington@gmail.com

On 8/1/2026 at 8:14 PM, Captain Obvious said:

What you understand, unfortunately, is not correct. The wrong key should never be able to turn.

If it is the correct key blank for that cylinder, it should insert just fine. But if it's not profiled to match the wafers (tumblers) in said cylinder, it should not turn. And if it does, it's because the lock is worn and should probably be replaced.

The reason I say "From what I understand" is because this has happened with two different ignition cylinders from 2 different 240Zs. One of which was already using an aftermarket ignition cylinder. The only difference is that the aftermarket one gave up the key without a fight once it got stuck. Maybe both were worn in the same way. I'm not willing to risk it with the recently unstuck cylinder just to see what happens.

Don't ask me why I repeated the mistake... part of the process was figuring out what key went to where. That's 6 keys between 2 cars. At least now the ones for what I'm currently working on are clearly marked.