I have had a lot of issues with Fuel going bad and the metal tank rusting. Ethanol is the devil. I think water gets absorbed but the alcohol in the fuel. Collects in tank and Wala, rust. I have seen it with my S-10 and other vehicles through the years. I plan to build a replacement out of Fiberglass with Vinyl Ester Resin. Evidently this resin is used for boat in floor tanks and it is chemical resistant. I am also going to rewire the fuel pump circuits. The power and ground supply routing are criminal. I welcome any advice and suggests, it's all food for thought. If any one is interested I plan on posting progress.

 

I noticed Hawks is selling a fuel tank now, calling it a reproduction- not sure what that means. https://www.hawksmotorsports.com/198...ion-14-gallon/

https://www.hawksmotorsports.com/198...ion-14-gallon/


You could also use a plastic 4th gen tank, a lot of guys do around here. I've been studying how to get the EVAP system working from 4th gens, shouldn't be a problem.

Fuel tanks require headroom and need to be able to expand and vent. should be into the EVAP system, but as a fail safe, to atmosphere. If you are really determined to get rid of metal, I'd go the 4th gen route.

 

I used a 4th gen tank for a while. The LSx fuel module is fantastic.

I just vented it to the atmosphere.

-- Joe

 

I also have swapped Fourth-Gen Tanks into many Third-Gen Cars.
The Pump and Sending-Unit/ Tank-Unit Options are great!

Note: I do not know how many of you are familiar with EVAP Systems, like a Stock Fourth-Gen would use...
But ignoring the purely Emissions aspects... The Fuel Tank needs to have access to Open-Air.
As Fuel leaves the Tank, Air needs to take the place of the Fuel... or the Tank will be under a strong Vacuum (almost like imploding)...
and cause issues with Fuel Delivery.

If any of you have worked on EVAP Systems, you would have noticed that the Fuel Tank Pressure Sensor reads in Negative values as well as Positive.
The EVAP System prevents the Fuel Tank from being under too much of a Vacuum.

 

I had not thought of it from this view point. How does it do this in the 3rd gen design? Basically, the Fuel Tank Pressure valve -FTPV, (the one that operates when the fuel tank pressure is high enough to allow vapors into the EVAP canister) opens under pressure from the fuel tank,the fuel tank must be at positive pressure. Is it opening under other conditions? does the mere presence of vacuum applied to its vac tube also force it open to prevent the fuel tank from building negative pressure? If this is what occurs, the service manual doesn't cover it. Its my understanding that basically, as the car is driving down the road, the EVAP canister solenoid is open, but I wasn't sure if this also opens the FTPV?

The only other thing I can think of, is it would be the fuel return line, keeping the pressure somewhat even.

 

woke up in the middle of the night, recalling that the fuel tank vent valve is a 2-way valve, maybe my dreams answered my own question

 

All the reproduction tanks are too small. 14 gallons is smaller than many of the original tanks. I would see if you could get at least 16 gallons in your design.

 

LOL, Small!
My 87 Camaro came with a 12 Gal. Tank.

 

The plastic (4th gen) tanks are 16 gal. So ive been told

 

I must have missed something. I read about this 4th gen swap. I started looking around (online) and found metal tanks. Perhaps I need to look deeper it to this. It's not the first time getting tripped up. This is why I posted this topics. I may have new options.

 

LT1 4th gens used the steel tank, LS models got the plastic ones.

 

The LS plastic tanks are 16.8 gal. With the removable fill tube this is a worthy upgrade

 

16.8, Even better than i hoped. Also no worries about rusting.

 

LS it is. I will look into this. Thanks guys, This is great info. Happy New Year everyone