Cottees' 1987 Sigma GN GSR Super Edition

[Cottees]

Question...Your exhaust manifold ,is that Sigma or Magna ??

It's a standard post-86 Sigma Astron 2 that came with a air injection on top, and a cat converter underneath.

[Cottees]

I took the rocker cover off to clean it up. I didn't bother taking the shield off. Once off, I got a good view of how the shield also is in front of the spark plugs.



Things starting to come together, and look shiny.





Made a quick holder for the O2 sensor plug. May need to remake it as it was a quick job.


A quick look to make sure things are fitting together.

[75glnt]

Nice

What did you use on the rocker cover?? Polish? Or a chrome style paint?

[Cottees]

What did you use on the rocker cover?? Polish? Or a chrome style paint?

It is cheap Export Chrome Paint. No idea how long it'll last, but for now, it looks awesome!

[75glnt]

Awesome! I just bought the expensive version and I'm looking at doing my grille that colour... I'll see how it goes

[Sigmaproject]

Question...Your exhaust manifold ,is that Sigma or Magna ??

It's a standard post-86 Sigma Astron 2 that came with a air injection on top, and a cat converter underneath.

Cottees, assuming that you still have the cat converter attached to the bottom of the exhaust manifold...does it still contain the catalyst ????

[Cottees]

Havn't dismantled it, but should still be in there.

[Cottees]

Cleaned up and painted some stuff to put back into the car.




Made a start on the air box in aluminium. First part I stuffed up the measurements and made it too small.



I was able to use the stuffed part in another part of the box.

[75glnt]

I wish I had fab skills/tools! I want to build a centre piece for my gb (the centre of the dash from top to bottom). Looks good mate

Is that blue overspray I see on the fan?

[Cottees]

Not overspray, but I did it on purpose. Just thought it would look interesting if one of the tips of the blades was blue when it went round and round. As for the metal work, it doesn't look as good close up. Once it has been neatened up, it'll be better. At the moment I am using some tin snips, a hammer and the edge of a table. With 0.5mm aluminium, it isn't too bad, but would be pretty hard with anything thicker.

[75glnt]

Yea that doesn't seem hard where do you get steel from? Bunnings?

[Cottees]

You can get 0.5mm aluminium from Bunnings. I have got 3mm aluminium from Paramount Browns, and they have up to 13mm.

[75glnt]

Cheers!

Also forgot to mention before about the fan.

Should look good spinning certainly different

[Cottees]

I have got the air box together. The photo makes it look better than it is. Will have to straighten and tidy it up still.

[Cottees]

I got the Sigma together enough to try a startup.
http://youtu.be/jAZbWPQVRqk

The tappets were a little loud to start with, but they are brand new. Once the oil was pushed into them, it was all good.

One good but unintended side effect of the intake heat shield is when the engine is spinning faster than idle, the fan blows cold air underneath the intake pipe and cools it down.

[bruggz351]

[Sigmaproject]

Cottee's... I am currently having a play with a TR wiring harness. Is that sensor on the side of the airbox housing the only sensor in that area ? All of the other wires and plugs in that part of the loom can be discarded?

[Cottees]

Cottee's... I am currently having a play with a TR wiring harness. Is that sensor on the side of the airbox housing the only sensor in that area ? All of the other wires and plugs in that part of the loom can be discarded?

That sensor is both the Mass Air Flow and Air Temperature sensors.

For the loom I modded, I kept all the sensors that were on the loom. The only sensor I have not used is the knock sensor. Since I am using a GN block, there is no hole to mount the sensor to. I have left that part of the loom connected in case I need it later. The way I did it was to pull all of the tape off the loom, lay it out with the wiring diagram, and work out what is needed, and what is not. Then that way when taped back up, it can be made to fit the engine bay better.

I should also mention, the ECU is throwing the errors 13 and 31. They are the "Intake air temperature sensor" and "Knock sensor circuit". The latter has an obvious reason, but since the engine is running, I can test out the MAF box to work out if it's the temp sensor that is not working, it if there is another issue with the loom.

[Cottees]

Today I tested the MAF, and the temp sensor wasn't working. Swapped it out, and the car started running a bit better.

Started to make up the brackets for the air box.



Now it can stand on it's own, and not sitting on the Fanta bottle of diesel that was holding it up.

[Sigmaproject]

I have been reading a couple of horror stories from guys that spent ages setting up the magna efi system in a Sigma using the magna ecu, only to never get them running 100%

I noticed also that you have an aftermarket ecu as "pending"

Do you think it would be a wise move to just give the magna ecu and wiring loom a miss...and just go for an aftermarket ecu in the first place (Like Haltech 500)

[Cottees]

If keeping everything standard, then the stock Magna ECU should be ok. The reason for wanting an aftermarket ECU is because I was planning on going turbo or supercharged. I have since decided to go supercharged and have a SC14 sitting waiting to get installed. For that, the stock Magna ECU will be no good. When the GN was on the road, it did 30,000kms without too much problems. The problem I did have was a broken loom and dodgy MAF. Now I have cut out the broken part of the loom, and soldered in a new section, and replaced the MAF, it all runs good again. The loom broke since I rushed and was a little too rough with the loom getting it fed from the engine bay to the cabin. With my setup, I have kept all sensors, and kept all of the emissions control. I have only left out the knock sensor. Without that, the engine runs fine, but will always throw a 31 error code. As for your question, if you are going NA, go for what works, a stock Magna setup. If you are going straight to force induction, go an aftermarket ECU.

[Cottees]

I have lost the keys to the Sigma, and I had to move it today. Lucky I have some spare keys.


The engine sounds like it vibrates when revved while cold. Goes away when warmed up. Think the actual noise is the heat shield rattling.
https://www.youtube.com/watch?v=SaIw0nkjCjk

[Sigmaproject]

Cottees...where did you locate your knock sensor ???

[Cottees]

Cottees...where did you locate your knock sensor ???

Since I am using a GN Astron II block, there is no mounting hole for the knock sensor, so I run without one. My custom loom still has the connector for the knock sensor, but with nothing connected. The ECU throws an error cause of it, but still runs properly.

[davenq]

Without sounding like an idiot ,can I ask why you ran your intake over to the "hot side", was it so you didn't have to mod the intake plenum? or ready for a turbo setup?...

[Cottees]

Since everyone else has done the cut and shut mod, I thought I'd try something different.

[Cottees]

A quick vid showing the vibration coming from the engine.
http://youtu.be/j9aDGYTvVv0

[Cottees]

Got the GN on the road. Not 100% to how I wanted it to be before getting it on the road, but needed a car to drive this coming week.

[Cottees]

With the GSR tow hook being red, it looks like she is sticking her tongue out.


Did some more neatening up. Also made and installed a support strap for the heat shield.

[Cottees]

I finally narrowed down why the steering has been stupid.



I can't believe I have missed it the other times I have been under the car looking for problems.

http://youtu.be/PmqUrDieDhA

I have put in another washer to keep everything together and in the right place. But next thing to be done is to swap out that cross member for a good one.