Cottees' 1987 Sigma GN GSR Super Edition

[Cottees]

I added a new accelerator cable mount.


The mount bolt holes kept stripping, so I stuck in some studs and glued them in.

[Cottees]

Was able to a little more work today. It is getting there.


Put it into the car to double check that everything, including the new accelerator cable, will fit. The coolant lines to the ISC will need to be shortened, and loom moved a little, but everything fits better than the old setup.

[Cottees]

I haven't been around much, and haven't had the time to do any work on the GN, but finally got some stuff done. Finalising the new setup and seem to be working ok. I have also added a air bleeder valve to the side of the idle air controller to bleed out any air from the top of the system. In the video, it is running a little fast, but after some tweaking, it is running properly. The end of the vid is just steam coming out of the bleeder.
http://youtu.be/N-0xFEDg9qE

[Cottees]

Got a little more tweaking done, under supervision.


I got the idle down lower than it did with the smaller throttle body. It was idling at times at around 600rpm. It is 660rpm in the photo.


A little more to do, but it is almost there.


The new accelerator is too short, but only by a little bit. I'll be able to make up an extender or something.

[Cottees]

Uploaded a video of how loud the intake is.
https://www.youtube.com/watch?v=9yWyI3e ... el=Cottees

[Cottees]

This is a shot of some of the new things on this setup.

[ozdusterdave]

This makes me glad I just run simple double carbs...

[Cottees]

This makes me glad I just run simple double carbs...

Carbs are black magic! Then again, I do run a Dell'Orto on my LC.

I was unhappy with how the TPS part of the loom was being run, so I extended it to run it neatly. If I was to do the loom again, I'd run the TPS wiring with the rest of the loom. I don't remember why I didn't originally.


I also pulled apart the TPS plug and cleaned up the pins since they have corroded.


Now the TPS part of the loom runs along the firewall instead of over the coolant pine and over top of the plenum.


I tidied up more of the loom, as well as the Sigma and Magna looms that runs along the firewall. Looking much neater. Just needs a little more sorting, and a good clean.

[Cottees]

The GN is now running, so I am unhappy with things with it and have to meddle again. I decided to change around the fuse box, as well as tidy up the wiring.


Instead of using blade connectors, I have soldered wires directly to the fuse box to neaten it up.


I moved the fuse box, and put new battery terminals on. Looks like the battery terminals have solved the issue of having the alternator light coming up when I start the car.

[Cottees]

She is up and running again with the larger throttle body. There doesn't seem to be any performance benefits that I can see, but there is still the benefit of fitting better. Just need to do some tidying, and that is about it.

[Scorpma82]

My guess is that the larger throttle may not give you more hp/Nm.....but it will allow you enough flow to make more hp/Nm efficiently with more work done on the motor (if applicable)

You've really cleaned up that engine bay too!! Top job

[Cottees]

Been a while since I have posted an update, so have done a couple things since the last post.

After driving the Sigma for the last month, there is a noticeable difference in power. I have temporarily changed back to stockies with 185s. Earlier when taking off from stand still, it would struggle a little, but then take off. Now if I do the same thing, I get wheel spin. A couple times I have pressed the accelerator a little, but not to the floor, and will still get a squeak from the wheels. Same thing with turning a corner, I have to be more careful now with how much I accelerate out of a corner as it is much easier to loose traction.

Front one is 185, rear is 225. I was going to try and get skinnier tyres on the mags, but for the rears, I'll be keeping 225s.


Once again the plastic intake pipe is starting to come apart like the last one, so it could be affected by the heat. I may make an aluminium pipe to replace it.

[Sigmaproject]

Cottee's..did you run into any coolant temperature issues by using the rear thermostat and piping it to the radiator? I would imagine you still use the Sigma head which has a very small rear water port that was mainly just to return coolant from the heater core. For this reason when I planned out my conversion , I also purchased a magna head to swap over. How have you found your running temperatures ?

[Cottees]

I am running a Magna M4 head from a TN-TP, and the roller rockers and cam from a TR-TS. I haven't had any cooling issues, even with it being 40C+ lately. I think I have a small coolant leak, and it would run hot when the coolant level dropped a bit.

[Sigmaproject]

Ok , I also have a M4 that I was going to fit. Bit of a change of plans atm and I am going to keep the carby turbo instead.

[75wagon]

I have removed some of the comments from this post (for various reasons).

If you were an author of any of the removed comments, and have a problem with it contact me.

Dave...

[Cottees]

I think I have a small coolant leak...

...That turned into a big coolant leak.

Looks like the gasket failed.


Had some help in double checking my work.


BOSOZOKU TIME!


I removed the mechanical fan. It just looks like I should mount something on it.

[Cottees]

After driving for a while, the water pump gasket was holding up, but there was another leak in the system, and also a leak in the heater core. The leaks weren't as bad as the water pump, but because of the extra heat, it made it worse. I ended up going through the system and making sure everything was cleaned and sealed properly.


While I had everything apart, I changed some things around and relocated the thermostat housing.


While things were apart, curiosity got the better of me and decided to check out the exhaust. Can see where the O2 sensor was sitting in the GN manifold.


Then came all the issues I hadn't noticed. It looked like it had started to leak from where the O2 sensor was sitting.


Then looking under that, there was a big issue. Like where has the catalytic convert gone? The GN came with the a cat converter, but looks like mine is missing. It could have been removed by a previous owner, or could have just disintegrated over time.


Looks like the gasket between the top and bottom parts of the exhaust has been leaking too.


Not surprising when looking at the gasket.


Instead of putting the leaky exhaust back on, I am putting a non leaky exhaust on.

[Scorpma82]

So I'm guessing ur going to tap/thread an O2 sensor in the new maifold???

[Cottees]

The metal isn't thick enough to tap, but I have welded in one of these O2 Bungs.

[A112H]

A112Hs Top Tip of the week

M12 x 1.25 wheel nut is the same as the bung and we all have them laying around

[Cottees]

Got the O2 sensor installed and wired up. It is running off cylinders 1 and 4. The Magna stock exhaust I think has the O2 sensor on cylinders 2 and 3. Either way, it should work ok. I was thinking of installing it when the pipes merged into a single pipe, but it would not fit under the car properly.

M12 x 1.25 wheel nut is the same as the bung and we all have them laying around

The common size for O2 sensors is M18x1.5. The bungs I got off ebay a while ago. I don't think they were that much.

[d3v147]

I originally copied your idea with the o2 sensor in the stock manifold and it always leaked even with copious amounts of muffler putty. Also the o2 sensor thread is definitely not 12mm, i'm wondering what this has been confused with!

[Kyle]

Does anyone have a wiring diagram for the digital speedo?