How I went about making an Alarm Key

[76FJ55]

Thought I’d do a quick write up on what I did to make a key for the alarm switch on my 84. I’ve searched and didn’t find a good source for these details, so thought this may be beneficial to someone in the future.
This is a project I’ve be wanting to do for a bit, not because of the need for an alarm, but because I like playing with locks.
Due to some interior work I’m doing I pulled the door panels, which has allowed me to opportunity sort out several issues with the internal door mechanisms. Difficulty to lock/unlock, passenger interior door handle stiff to move mirror switch issues… This gave me the opportunity to remove the alarm switch from the door to devise a plan to create a key.
My research found that an Ilco X9 key blank was a suitable match to the key way and commonly available. So I picked up a couple blank, at a couple dollars apiece, for experimentation. One not on the X9 blank; even though the key fits the keyway, the height of the uncut key is slightly taller that the hole in the wafer tumblers. I used a large flat file and removed a few thousandths from each side of the key until the key blank could be inserted into the cylinder without binding. This also gave a nice smooth surface to check for rubbing of the wafers to identify where each cut needed to be located on the key.
The first order was to disassemble the lock to gain access to the cylinder and wafers. When looking at the plastic housing the only thing I could find was a seam line along the back face, where it looked like the back had been bonded onto the body. I used a sturdy utility knife to score the body and cut the rear face off to gain access to the inside of the lock assembly.



Once the back was removed the rest of the disassembly was fairly self-evident.




I fully disassembled the outer cylinder from the plastic body. I would suggest NOT doing this. There really is nothing gained by removing the C-clip and outer cylinder from the plastic body, and it is extremely difficult to reinstall. The rubber gasket between the plastic body and mating face of the outer cylinder need to be compressed to enable the C-clip to be reinstalled. I ended up having to use a piece of cope pipe and my press to get the C-clip to fully seat again.
Upon removing the lock core I was shocked to find so much contamination. I have no idea what the PO put in this lock, but if it was in an effort to try to improve the movement of the lock mechanism it was a complete failure.



Most of it just crumbled away, then I followed up with carb cleaner to finish cleaning everything. Be warned at this point there is nothing holding the wafers and spring in the lock core, so I would suggest working over a clean shop towel or similar so you can easily find any parts which may fall out. I removed each wafer and spring and laid them out in order so I could fully clean the slots in the cylinder, and ensure all the wafers themselves were clean as well. Also this is a good time to check to make sure there are no burs on the sides of the wafers that may keep them from moving freely in the cylinder. If you have any high metal on the faces of the wafers, you can smooth them using fine sand paper or a flat file.



With everything clean it was time to start working on cutting the key. For this I installed a single wafer (without the spring) at a time, and filed the key for that location. Since I was concentrating on the depth of cut initially and not the ramp angles, not having the spring installed allowed me to turn the cylinder over and freely removing the key without the wafer riding against the newly cut key. Once I go the depth cut as desired so that the wafer was centered on the cylinder and didn’t protrude out either side when pushed against the key (go slow, if you overdo it you will have to start over with a new key blank), I then filed the sides of that cut location to form the 45 degree approach/departure ramps. If you have to error on either side I would leave the key cut slightly too tall. You can always come back and remove a little to touch up the wafer position, but you can’t add any material back to the key. I continued with this process till I had all the wafer locations on one side of the key finished. I then repeated the process on the other side of the key. To save on confusion I marked one side of the key head with a sharpie and the corresponding side of the cylinder with the sharpie as well. This helped save on any confusion on which way I was to insert the key each time. When done I then had a key that would work in the lock but only in one orientation.




The final step was to create the standard double sided key so that it would work in either orientation. For this step I utilized a sub-contractor (couldn’t justify the purchase of my own key cutting machine, though I was tempted). I took my hand filed key to the local locksmith and asked him to run both sides of the hand filed key to each side of a new key blank, to which he promptly replied, “That won’t work”. I assured him that I was confident that it would and that I’d buy the key, success or failure. He cut the first key and handed it to me, where I inserted it into the lock core I’d brought with me, and low and behold a fully functioning double sided key. I went ahead and had him make me a spare for safe keeping encase something were to happen to the first.



The final stage was to verify the operation of the switch and reassembly in revers of disassembly, with the last stage being to epoxy the back on to the plastic housing.

Disarmed:


Armed:


Hope this may be helpful for anyone who has a car with a factory installed alarm, but no alarm key.

Simon

[shadowjack1]

Great write up.

[Litle brother]

Great thread


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[rokemester]

Well done! I took the lazy way and after searching for a locksmith that works on older cars found someone and gave them my alarm switch. After a couple of weeks and $50 later I have a couple of working keys. No idea if the stock alarm system works. That will be the next adventure. Several good threads in this forum for that!!

[76FJ55]

Originally Posted by rokemester

Well done! I took the lazy way and after searching for a locksmith that works on older cars found someone and gave them my alarm switch. After a couple of weeks and $50 later I have a couple of working keys. No idea if the stock alarm system works. That will be the next adventure. Several good threads in this forum for that!!

Can't say if my alarm is fully functional, but I know it definitely triggers when the alarm switch is unplugged if the battery is still connected. It startled me pretty good when I pulled the first plug off the switch, which i was then in a panic to reconnect. Car is sitting with the battery disconnected until I get a chance to reinstall the alarm switch, hopefully this evening.

[DSul]

Originally Posted by rokemester

Well done! I took the lazy way and after searching for a locksmith that works on older cars found someone and gave them my alarm switch. After a couple of weeks and $50 later I have a couple of working keys. No idea if the stock alarm system works. That will be the next adventure. Several good threads in this forum for that!!

Is your locksmith someone you found online or someone local? I'm currently looking at my security lock switch sitting on my desk trying to figure out how to get keys made for it and the first locksmith I called gave it a 10% chance of success. I'd prefer that route to trashing the lock by cutting open the casing

[PCA7GGR]

If I recall correctly, the key for the lock for a rotary dial telephone is the same as for the ‘80s alarm. A long established independent locksmith might have some that he’d be happy to find a new home for.

Just a thought

[kltarga72]

When you are testing the switch with the DVM it looks like you have selected the ohms setting. So is the meter showing a 4.74 and 2.6 ohms with key turned on and off? I thought you should see either continuity or an open circuit when key is turned on and off. I'm assuming that you do not have 12vdc applied when testing.
I do not have a key for my alarm and maybe I should see if a locksmith could help me with this issue.

[Nick Triesch]

I think I would be terrified to twist on the alarm on my 36 year old car. God knows what would happen! I think there is a reason that no one has the alarm keys any longer. All I know is for 11 years my 911 has started without a problem. Want to keep it that way!!

[targa80]

I did not get the alarm key when I bought my car in 1991. The alarm shutoff location on the drivers door always made me shake my head and ask why? Eventually, I came up with an alternate solution that eliminated the key lock on the drivers door. The thread below explains how I integrated the factory alarm with a keyless entry system (KES). If you only want the alarm to be activated or disarmed by a keyfod then a KES will do the trick. You don’t have to install the door lock actuators if you only want the alarm armed or disarmed by a remote keyfob.


https://forums.pelicanparts.com/porsche-911-technical-forum/819248-added-keyless-entry-my-80sc-targa.html?highlight=Keyless+entry