I've been encouraged to update this thread with some more stuff.
Since my last post I have been concentrating on stripping out the rest of the ICE parts and unneeded components.
This has been 'fun' and simple things like removing the fuel tank was a little bit of a pain.
The fuel tank in an MR2 is in the transmission tunnel. I had the car as high as I could on stands on one side on the basis of sliding the tank out. To access it I needed to remove all the under floor panels which meant the loss of a number of small M6 screws to rust. I will need to drill out and retap these for replacement at some point.
The tank itself is trapped in the tunnel by the aircon plumbing, vacuum line, speedo cable, clutch pipe and hand brake assembly It is also long, tall and mis-shapen mass which just adds to the fiddliness. The fuel lines were numerous but at least, unlike the heater pipes, easy to undo.
I have also been working on ideas for the vacuum pump for the brake servo.
I began with a Saab pump I bought on Ebay.
I did try it on the car but found that it made little difference to the servo. With or without the pedal felt the same.
I needed another option and decided to look at what I had available.
I decided to try the AC compressor as I hve heard of these being used as engine driven air compressors on Land Rovers. So to check if it would pull a vacuum I bought a vacuum gauge and tried it.
It managed to pull 10"hg just by turning the pulley by hand.
To determine if it would work when driven I set up a test rig using a 1ph motor and belt to drive it in the workshop.
I also needed a reserviour for the vacuum so looking around for something else free I decided to use an old dry power fire extinguisher.
I cut the handle and nozzle off on it and poured out all the powder.
I then added the reserviour to the vacuum rig and tried it again. I used a ball point pen tube taped to the pipework and it leaked a little but was enough to see the effect of the vacuum.
The AC compressor was able to very quickly pull 11"hg and maintain quickly as it was lost. The electric clutch was also working well for a resonable hysterises on the vacuum level.
I set up the rig to test it on the car
It worked! The 11"hg was fine giving good pedal and the compressor was ble to make up the lost vacuum very quickly, within a couple of seconds. I was also able to get 3-4 pumps of the pedal on the vacuum within the pipes alone so the reserviour will be ample.
For a vacuum switch a kindly EV converter from the DIY Electric Car forum sent me a spare switch he had removed from a commercial heating system. he had two and was using one on his brake setup. The switch will allow me to control the elelctric clutch on the AC compressor.
I had my working compressor, gauge and reservior so I then needed to work out how it would be installed. I decided that the AC compressor could be driven by the drive motor. The assumption is that it could pull a vacuum so quickly that I would have full assistance by the time I was off my driveway. It would save me having a second motor, it was quiet, it was designed to have a 100% duty cycle, it could be electrically controlled, the plumbing was already in place.
With the compressor attached to the drive motor I would use the existing vacuum side of the AC plumbing that lead to the front of the car. It would then pull from the reserviour and also from the servo and gauge in the instrument panel. The switch could be located near the compressor as I could reuse the original vacuum pipe from the engine.
For the additional plumbing I would use plumbing pipe.
To make the reserviour useable, the plastic top of the reserviour was then turned on the lathe to 22mm. This allowed me to use plumbing fittings on it.
This is the set up I decided on laid out in the car.
The vacuum gauge was then installed in the dash instrument panel.
I decided to remove the fuel gauge and modify the panel to take the new gauge.
It was the first bit of really fiddly work. The original fuel gauge is fitted on a slant to fit the curve of the panel face and the back of the panel is full of moulded shapes and lighting channels.
I took the vacuum gauge apart to figure out how best to fit it thinking that without its case it would be easier. Not good. I managed to bend the bourdon tube as there was nothing else to hold. I bent it back though and then spent ages trying to zero the gauge again.
In the end I cut the back off the original gauge housing and refitted it to that before trying to fit it to the instrument panel. It was difficult to line it up with the round opening in the panel front due to it being on a slant What looked right didn't end up right once the panel was snapped shut so it needed to be popped open a few times.
The flexible circuit board also clashed with the vacuum connector and I had to cut the circuit board and reconnect the cut circuits with soldered wires.
It eventually was as right as I could be bothered with and I refitted it to the car.
This is what it looks like fitted with and without lights on. I was getting too frustrated to remember to take photos of the process.
The new vacuum gauge is electroluminescent and so doesn't match the rest of the instruments. I wasn't happy about this as I would have to look at it every time I drove the car so I decided on an extravagence. I am buying a set of Speedhut EL dials so the instruments will look like this
I joined a group buy on the MR2 forum and it meant that it was 20% discounted and with free postage.
My next task was the removal of the heating system.
To get at the heater I needed to remove the whole dash board. This was a real pain as it is not an easy task.
This is the process.
The dash bolts are well hidden.
Taking out the glove box and the steering column surrounds is fairly easy. as is removing the centre console and all the stereo and heater controls.
There are two bolts, one at each side of the dash at the bottom corners near the door check straps.
Then there is one bolt behind the centre of the instrument pod which also has to come out.
From the instrument pod hole there is another bolt tucked well inside the dash towards the corner of the wind screen.
It's twin can be accessed by popping off the corner heater vent on top of the dash on the passenger side.
Remove the heater vent pipe that goes under the steering column.
The dash would be loose now except that you also have to remove the door surround trim. You can carefuly pop it off on the driver's side and unhook it from the rear quarter trim to save removing the seat belt and the rear window surround. Yes, to remove the dash the rear window trim should come off!
The passenger side door surround needs the grap handle removing. Be careful with the bolts from that as there is a spring plate, a square washer, the end of the handle and the back part of the end cover and they have a habit of just pinging off across the car. The spring plate has a squigilly tab at one end, that bit points towards the middle of the handle.
The door surrounds are very long. They start at the top back corner of the door opening at the B pillar and go all the way down the side of the wind screen where they hook into the dash, preventing the dash from coming out, and then a long thin strip continues down the A pillar to the bottom.
Now the dash is ready to be pulled away from the base of the wind screen.
However, you may not be able to remove it without removing the steering wheel and the top half of the steering column and the stalks.
I managed because I have a really small steering wheel and I managed to lower and extend the column while wiggling the various bits of the dash over the stalks, steering column, hand brake lever (needs to be up and down at various points), and the gear stick. The gear stick on mine is not attached to the gearbox and so has a wider range of movement to make this easier. If the steering column is removed then this may not matter.
The dash is heavy and unbalanced so careful of the seat fabric as it comes out.
To get the heater out there are a couple of 10mm AF nuts at the top to the bulk head.
Then remove the funnel to the windscreen demister.
Then remove the steel support that joins the passenger side of the tunnel to the round rusty tube across the bulkhead (Why do they never paint or galvanise this part? Every car I've seen with one it is unprotected and rusty!).
Disconnect the cabling.
Disconnect the hoses in the frunk and also the short cable to the heater valve.
Pull the heater from the passenger side and also push the pipes through the bulkhead sort of at the same time and wiggle it. It won't fit under the rusty tube but does flex enough to pop under it.
Then mop up the rusty water that is now pouring into the passenger foot well!
To remove the heater core DO NOT dismantle the heater box as I did.
On one of the heater core pipes there is a metal bracket screwed to the plastic heater case. Undo the screw and the core pulls out.
Here is the heater core
I decided to look for a free method of converting it to electric so I dug out some old fan heaters and tried the elements from them.
I couldn't find a matching pair that fitted so I decided to put the car back together while I though about it.
That would give me a problem, I though, as I would need to dismantle it all again to try an electric heater when I found one.
To get around this I decided I could cut a hole in the bulkhead where the heater was.
I will cover the hole with a nicely panel beaten plate.
As I was reassmbling the heating system I noticed that the old aircon core was covered in rotting leaves, dead flies, greasy gunk, etc and I didn't want that lot ending up on my electric heating element. I decide to put a filter in the aircon box. To do this I used some aluminum mesh for car body repairs. It is fixed with double sided tape.
The filter could be changed, cleaned and better fixed quite eaily as the aircon box comes out without the dash removal.
As I completed the reassemble heating ssytem and patted myself on the back over the bulkhead hole and the removable aircon box filter I then realised that I could have left the bulkhead intact and just put the heater in the aircon box. Doh!
Anyway, I still needed a heating element on the cheap and this is what I finally came up with.
It is three cooker rings. Each element is 1.5kw at 250vac. Measuring the resistance of one gave 43ohms. At 144v that gives 482 Watts.
I decided to put three together. The fun part was trying to 'weave' three elements together to make one compact unit with a good air gap between the elements.
It was like one of those annoying puzzles made up of some bent nails that need to be linked together or separated.
To switch it I would either need a very big relay or something solid state.
A chap in New Zealand who is also building an EV on an MR2 like mine suggested a PWM device to control the element. So I have decided that a cheap motor controller from Ebay will do. It can be controlled by the temperature slider on the heater control panel.
Anyway, that is where I am up to now. I hope you have found it interesting.