Door Poppers

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Major System Category: Body (Door)
Task: Install door poppers
Parts: Popper solenoid, cable, pulley
Prerequisite Tasks:
Additional Costs: $75
Time Requirement: 4 hours
Date Started: November 21, 2012
Date Completed:  November 25, 2012

One of the issues I worry about is security. These cars attract a lot of attention. Chances are people have never seen a GTM.  I decided to go keyless early in the planning stage. This means the normal form of ingress (i.e. door handles) needed to go away. I'm not going to go into detail on the security system, except to say it is multi-layered and bio-metrically keyed to me. Yes, if I have a dead battery, she's going to be hard to start.

These are the pulleys and the solenoid base plate.

The first security layer is to eliminate door handles and rely on door poppers to open the door. There is a need for a manual override, and I have something in mind for how I am going to put that together. To operate the poppers I have a fob. The fob is linked to the RFlink module installed in the ISIS master cell. However, the fob can only get you into the car. It has nothing to do with starting the car.

The rear of the solenoid where I attached power and ground leads. This is clamped in a vice. I did  all the electrical work down stairs in my cave, as the temperature was dropping through out December.

I am using 60 lbs solenoid door poppers and a plungers to push the door open past the striker. The plungers (like the striker) need to be installed after the engine and transaxle are installed. The plungers need to be secured against the chassis and installed through the body shell.

The solenoid popper is bolted to the mounting bracket. The steel cable is looped around the end of the solenoid and the clamp is in place, but not compressed. Yes, they don't make vices like this any more. It was purchased 60 or 70 years ago.

The latch has a vertical orientation. The idea behind the popper is a solenoid attached to a wire cable that fires (i.e. contracts) been an electrical charge is applied. Unlike the rear hatch popper, it is not possible to position the solenoid so it is in a straight line to the latch.

Close up of the pulley with the steel cable threaded. At this point nothing had been tightened down, so that is why there is slack on the line. The pulley is riveted into place. You can also see the narrow end of the internal brace. Things are very tight on the rear edge of the door.

The solenoid works on a electrical charge that fires the solenoid causing it to contract into the housing. I attached five feet of 16 gauge wire for power and ground. This has to be threaded out of the door and into the front hood area where it gets connected to the power cell and grounded at a ground point on the chassis.

The popper solenoid and pulley before the steel cable is tightened into place. The cables from the window motor is just to the right of the popper solenoid and the black bracket in the middle of the photo (behind the brace) is the window track.

I use a 12 volt test battery to verify the connections are working and that they are solid (this is a lot of fun - it's a guy thing). The solenoids come with a heavy bracket. This is mounted to the bottom of the inside of the door. I used short bolts and nylon nuts to secure it in place. The last thing I want is for the popper solenoid to slide loose inside the door.

Everything is tightened up. Note: There is still some slack in the steel cable.

The idea to use a pulley and form a right angle between the latch and the popper solenoid is not original with me. I don't remember where I first saw the idea, but it really works. The pulleys are quite simple (a $2 part at Lowes). I think I found them in the screen door section. The pulley allows me to create a right angle between the popper solenoid and the latch. I riveted the pulley into place and checked for strength.

I threaded the steel cable from the latch, through the pulley and to the popper solenoid. The cable loops around the solenoid end and is crimped using the two channel clamp. If you lose one of these clamps, there are available at the little parts area where they sell pulleys at Lowes and Home Depot.

Once everything is tightened down, I retrieve my test battery and fire the solenoid. There is plenty to check:

1. The door latch actually opens.
2. The pulley doesn't stress.
3. The bracket holding to solenoid doesn't stress.

I fired the solenoid about twenty times. There is a significant bang each time. 

Rear Hatch Release Popper

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Major System Category: Body (Hatch)
Task: Install hatch release popper
Parts:
Prerequisite Tasks: Assemble and mount hatch latch
Additional Costs: $42
Time Requirement: 2 hours
Date Started: September 14, 2012
Date Completed:  September 20, 2012

One goal I have for the car is to eliminate keys. It might even be possible to eliminate fobs and rely strictly on a smart phone, but I'm not quite sure I want to be that radical. To this end, how do I open and close the hatch?

45 lbs solenoid mounted to the edge of the body shell in a direct line to the hatch  latch.

The kit solution is a very long cable snaking from  the rear hatch to the cockpit that needs to be pulled and the hatch opens. By the time I looked at this, I was two months into the build and a certain skepticism was developing as to how things will hold up long term. I really don't like the cable idea. So I have moved on to a popper solution. I am also planning to go with door poppers as well. Two door and trunk popper kits are available on Ebay at reasonable prices.

Steel cable looped through the eye of the latch and back to the solenoid. I still have the red  zip tie attach. This my emergency release cable. I will need to replace this with a steel cable once I install the engine.

The popper is a simple device. It is a looped steel cable threaded through the eye of the latch release and connected to a solenoid. I have a 45 lbs solenoid for the trunk and 60 lbs for the doors (this is a measure of pull energy for the cable, not weight.) The popper solenoid is grounded. The power lead will be connected to an ISIS power cell and ultimately controlled by a touch screen control.

These clamps are holding the solenoid in place as the 8115 sets up overnight.

The cable between the latch release and the solenoid works best on a straight line basis. Certainly, a pulley can be added for angles, but this just becomes another point of failure. Since the latch is mounted to the body shell, I mounted the solenoid to the body shell, and this is where things get interesting. There really isn't a good place to do this. Absent an engine, transmission and exhaust, this area looks wide open - this is a mirage. The exhaust exits on both sides of the license plate and this sits right below the latch.

These are the electrical butt splices I used to clamp down the wire. It is a tight fit (which is fine), but you can get the steel cable through these connects twice.

My solution (for now) is to mount the popper solenoid on the body shell using 8115 adhesive (this stuff is incredible. I would like to reinforce this mount with some kind of strap. I did not like the little lead wire clamps. I figured if something got messed up and I had to take things apart, then I would need a replacement for these. I discovered that I could use a 10 gauge electrical butt splice and make everything work.

This is my little test battery. It weights about four lbs. I can duct tape it to the lift, and it is rechargeable.

I measured everything out, looped the cables and clamped the splice. Then I used my little 12 volt test battery to make sure everything works according to plan. These are great little sealed lead acid batteries for testing individual circuits. To test that everything works, I just touch the leads together and watch the solenoid fire. Great fun to see something actually work.

All done. The steel cables are clamped. I covered up the parts that could cut someone's hand with wire loom. I will see how well it stands up when I remove the body shell next summer.