1963 AP5's dirty old '82 Sigma SE

[1963 AP5]

Well I haven't been very good at keeping you all up to date with what's going on in my shed lately so I thought I should try a little harder and share this with you.

 

A few weeks ago I spotted this 1982 Sigma SE on the side of the road in Ohope and decided that it had to be mine. It ran like crap, but it is very tidy and most importantly is rust free. I have been busy working on getting it running properly. The car was on LPG for many years and the factory carb was pretty much useless. I have fixed this problem by installing a 32/36 Weber and she runs sweet now. Photos and details to follow.

Discuss the project and/or mock me for my ridiculous life choices here

 

[1963 AP5]

The first task was to replace the factory carb. I pulled the plugs and it was obviously running super lean and on top of this i am sure that the vacuum secondaries weren't working. I couldn't find a rebuild kit for it so replacement seemed like the best option. I went for a 32/36 Weber because I have had good results with Weber's in the past and I find they are easy to configure and tune for different applications.

[1963 AP5]

And here it is installed on the car

[1963 AP5]

I managed to rework the throttle cable hardware from the original carb so it would work with the Weber.

It was a little fiddly but ended up working very well.

[1963 AP5]

The throttle cable bracket took some figuring out but I got it all working with the factory cable.

[1963 AP5]

In the 1980's car manufacturers seemed to think it was a good idea to supply their customers with unnecessary and unsightly additional ride height. Last weeks project was to correct this with new springs and shocks all round. The car didn't drive particularly well so I did a back yard wheel alignment with string and a tape measure. I found that the front wheels were actually toed out so I also corrected that problem and it drives heaps better now. I will get it in for a proper wheel alignment sometime soon.

[1963 AP5]

Here you go @MaxPower

The front springs were just a little loose with the car jacked so I made them secure the oldschool way with some locking wire.

[1963 AP5]

The Sigma has been sitting around a bit. I drive it every so often but it's kind of underpowered compared with my Aussie 6 cylinder stuff and I really wish it wasn't. I have been toying with the idea of repowering it but I thought I might try to liven up the stock engine first. A buddy of mine dropped this off over the weekend. I really have no idea what I am doing but that has never stopped me in the past. What could possibly go wrong?

[1963 AP5]

If anybody knows where I might find an inlet manifold for a RWD SOHC Mitsubishi 4G63 engine please let me know.

I will need one to hack about (modify) in order to make this work.

[1963 AP5]

Big thanks to @MaxPower for helping out with a spare manifold from one of his vans.

I checked online and for some reason you can buy a supercharger manifold for your Corvette or Mustang but there is no off the shelf option for your 1982 Mitsi Sigma.

I will have to make one, what could possibly go wrong?

I will post more pictures as the manifold comes together

[1963 AP5]

Another quick update, got some welding done on the manifold and did my best to smooth out the ports etc.

I am sure the design is far from optimum but I think it will work.

I made some more bits to box it in.

Now more welding....

 

[1963 AP5]

I got a bit more welding done on the manifold.

I'm not welding this myself, I have a good friend that is a very good aluminium welder/fabricator and he is doing the welding for me. I am making all the bits and he is sticking them together for me. I certainly couldn't weld like this!!

Now I need to cut a hole in it so I can attach a flange for the supercharger.

 

[1963 AP5]

Big progress today.

Now I need to figure out the drive system. I am planning on running an idler shaft down where the air conditioning compressor would be. This is necessary as the supercharger drive flange is positioned well behind the crank pulley. With this set up I will be running the supercharger via two drive belts but it seems like the most practical solution and will also avoid clearance issues when the distributor is reinstalled.

Right now I am liking the look of this.

 

[1963 AP5]

I figured I should probably have a look inside the engine to see if its actually worth the attention I am giving it. Good news is it seems to be in great condition, it's very clean so must have been well looked after over the years. It might even survive with the new belt driven intake.

I am also having second thoughts about the carburettor choice for this set up. I have been doing a lot of research and it seems that the Weber is not well suited to a draw through application. It seems that a 350 Holley is a much better option (as previously suggested by @RUNAMUCK). There is plenty of info available on modifying the power valve for boost reference so I will probably put the Weber to one side and look for a Holley to play with. If anyone has a decent 350 Holley that might be for sale please let me know. 

 

 

[1963 AP5]

This weekend has been all about making some brackets so the supercharger isn't just dangling off the manifold.

I am going to use an electric fuel pump so I decided to repurpose the fuel pump mounting location and made a bracket to support the lower supercharger mount.

The upper mount is fastened back to a couple of studs on the engine that used to support the air filter assembly, I hope this is strong enough but didn't really have a lot of other options for this one.

[1963 AP5]

The next challenge is to figure out how to get the fuel/air from the fuel delivery device to the supercharger. Space is kind of tight so I decided to build a manifold that comes forward of the supercharger otherwise I will be cutting a hole in the bonnet. After a lot of head scratching and mocking up with paper, cardboard and plywood I arrived at this solution. Shaping the metal is a real challenge but it is coming together alright. 

I started to make the flange for mounting the carb but I ran out of weekend before I got very far. It will be kind of large to accept a Holley 2300 flange but I am sure I will be able to trim it down when I have the exact position of the carburettor sorted out.

 

[1963 AP5]

Another dozen Steinlager to the man with the aluminium welding skills and another little bit is stuck together.

 

 

[1963 AP5]

So I have been waiting for essential parts to arrive from overseas and have been keeping myself busy with little things.

The manifolds are all fitting nicely and all I need to do is trim the carburetor flange to size so it looks a little more attractive. I will wait until I have the carburetor mocked up in place before I do this to make sure I don't run into any clearance issues with the throttle and transmission linkages etc. It all ended up fitting very neatly around the strut tower and the carb should end up in a reasonable position with sufficient hood clearance.

I also decided to fit larger fuel lines as the factory ones seemed very small. This is probably more for the future but since I am installing an electric fuel pump now I figured it was best to do the fuel lines as well. I removed the factory 1/4 inch return line from the car, and from the tank pick up assembly, and replaced it with a larger line that will become the fuel feed line. The original 5/16 fuel line will become the return. Bending all that hard line into the correct shape to fit with the factory lines was a challenge but it all turned out pretty well and looks neat and tidy installed in the car. I had to pull the driveshaft out to get access but no big deal. 

 

[1963 AP5]

Amazingly a few parts have shown up during lockdown so on with the show!

The fuel pick up strainer arrived so I got the fuel pick up reinstalled and also mounted the electric fuel pump.

I started installing the fuel lines however I ran out of 5/16 fuel hose so the last little bit will need to wait.

I got the position of the fuel delivery device sorted so I trimmed the manifold flange, I am happy that everything fits right where I planned so that's a win.

Old bogans will recognise the unmistakable shape of a Holley 2300 flange.

[1963 AP5]

Nothing else to do this weekend but hang out in the garage and make brackets and fittings.

Made a beefy bracket to fit in the A/C position, this will provide a mount for the supercharger drive layshaft, the forward belt tensioner and anything else I might choose to attach to it. Apparently Argon is not essential so I wasn’t able to purchase any. In this situation it was out with the trusty little Lincoln Electric arc welder to stick the bits of metal together. Everything went together well and the bolt holes even lined up when I was finished.

 Made an unnecessarily fancy brace for the manifold that may or may not be necessary and also made a fan shroud for the electric fan.