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Using a 99 GST to build my 99 GSX

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SwiftKidGSX

15+ Year Contributor
100
7
Jul 11, 2003
Cerritos, California
Its been 15 years this project been on hold and forgot everything as to what bolt goes where and part.

It had a Japan 6bolt motor before so all that wiring is in place and I will be reverting back to a US 7bolt. I was then working towards a 2.4 build using the hyundai sonata block formula.

I have a few questions before I pull the trigger in purchasing a lightly damaged 99GST and would like your thoughts and see if what I'm about to do is smart...The plan in purchasing the GST is to have a guide to know where everything goes.

Is the gas tank and lines that run under the car a direct swap? It still has the old gas of 15 years.
My HKS cams 264|272 have very light rust on the lobes, are they still functional? Or don't risk it.
Are the 660 injectors still good or get new ones?
Are both ECU's the same?
No issues with the CAM angle sensor, right?

I know I would be rolling the dice on the car's engine health here but this is just to the GSX rolling and have a heart beat again and slowly build it back up.

Thanks for your input and advise fellas.

Joey
 
JPenny is right, the tanks are quite different, but the physical lines are the same. Years ago when I converted my old spyder to AWD, I never swapped any lines out. Used the FWD lines with the AWD tank and everything mated perfectly. The ECUs are basically the same. You can interchange them without problem. The only difference is the GSX ECU is rated for a slightly higher top speed.
 
I would buy the gst engine bay harness if you do. For a reasonable price that is. I'm still using my 99 gs spyder harness. Now that I think about it idk if there is a difference between the spyder gst and reg gst so I guess I'll have to research that first before pulling the trigger.
 
You can always get the injectors flow tested and cleaned if you want to make sure. $100 for cleaning is a lot better than $200-300 for new imho. I wouldn’t run them as-is, though. 15 years of sitting is a long time.
 
Your going to need to clean or replace the tank. This is a tank I had that had 10 year old gas sitting in it. That brown stuff isn't rust it's a build up of varnish on the tank. I sprayed it off as best I could with a pressure washer. You have to use hot soapy water and let the tank sit in the sun and get as hot as possible before you do it so the water evaporates out when your done. You'll still get some flash rust but it's better than all the varnish
1st Pic is before any pressure washing
2nd pic is the same tube and bracket after a little bit of power washing. I spent about 2 hours total and had to cut 2 holes in the tank to get around all the baffles. Then weld and braze them shut for a leak free seal
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IMO.
 
The fuel tank won’t be that bad but a clean would be nice to put some fresh fuel.

The gsx fuel tank is rubber which it builds no rust, on the other hand, the gst fuel tank is metal, that will build rust like hell.

Post some pics of the cams to see how deep is the rust, if it’s very light, a light polish would get the rust off.
 
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The fuel tank won’t be that bad but a clean would be nice to put some fresh fuel.

The gsx fuel tank is rubber which it builds no rust, on the other hand, the gst fuel tank is metal, that will build rust like hell.

Post some pics of the cams to see how deep is the rust, if it’s very light, a light polish would get the rust off.

Thanks for the reply's fellas! I found another GST with a 6bolt! Its been sitting for a while.

I will post pictures of the cams when I start pulling and organizing everything out.

I got to say I feel like a kid in a candy store if you know what I mean!
 
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Hi Fellas - Here are the pictures of the cams, the rust is raised away from the lobe, thought rust eats steel, its raised here..

Thanks in advance!
 

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Finally pulled the engine out and will be be getting it on the stand to build it back up. Swapping out the oil filer housing with an old one since that one is water cooled.

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Took the turbo to get rebuild at PT Turbos (Performance Techniques) and was shown the exhaust housing was cracked. Glad I took it since I didn't even notice it.

Took the injectors to RC Engineering to get button up, they are getting machined with new internal seals.

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I also pulled out the fuel pump to also take to RC Engineering but it was in no condition to even bother, going to replace it. 15 years has taken its toll inside the gas tank. The fuel tank gasket [Part# 05261] and the bottom rubber part of the fuel pump turned into sticky GUM. The gasket cost me $36.25 at the dealer.

My plan in the future is to run e85, what fuel pump should purchase to get that checked off? For now it will be 91 octane on 660 injectors, 20G.

Thanks!
 
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