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Mounting in tank pump

3K views 7 replies 6 participants last post by  jakeg214 
#1 ·
I bought a Rock Valley EFI tank for my project a while back off Ebay. It's new never used, the seller changed plans.

Not too long ago I decided to see what fuel pump was in it, to make sure it had enough flow for my LS3. Turns out the tank had a low flow low pressure pump in it suitable for a stock TBI system!

So I bought a Walbro GSS340 pump, 255 lph to put in it. The GSS340 is slightly taller than the original, so I'm going to have to modify the mounting to even get it in the tank.

My question is does anyone have any guidelines for how far the pre-filter (sock) should be off the tank floor?

I'm thinking maybe it could be right on the tank floor and be ok. The pre-filter has a 1/8" plastic rib in the center to keep it from collapsing any more than that. The original filter was not quite on the bottom but the reinforcement in it was thinner too.

I did some searching but couldn't find any info on this.
 
#3 ·
No sump. It has a spiral baffle that should be very effective. When I say spiral, think of a 4" cylinder that runs the whole height of the tank, and the cylinder is split lengthwise into a spiral shape. There's about 1/8" gap at the ends of the spiral. So when the car is at rest the fuel level inside the cylinder is the same as the rest of the tank. When you accelerate, decelerate, or corner, that level of fuel tends to stay inside the cylinder, no matter what the fuel does in the rest of the tank.

Part of the reason for asking is that with an engine oil pump, it's usually recommended that the pickup be 3/8" off the bottom. But that pump flows more, and oil is thicker than fuel. Plus fuel can get in the pre-filter from top and bottom, unlike an oil pump pickup.
 
#5 ·
Is yours a wagon? Mine is; and my tank is a Rock Valley that was discontinue supposedly due to insurance (not reliability) issues??? I also bought via eBay. I can only attest that mine has been trouble free so the pump mfr. (which is unknown to me) hasn't been a problem. Hope this helps.
 
#6 ·
49cadillac, no I have a sedan. I bought my tank from an individual, not direct.

Rock Valley is still selling tanks, in fact I called them about the pump pickup and got an answer. They use Walbro pumps.

I could have just bought a pump module from them but I figured that modifying what I had would be much cheaper and quicker. So I didn't even ask.

I have not completed the mods yet but should do so soon.

Their fabrication is very nice stuff. I just need to make mine to where it has the proper pump. Not their fault by any means. I like their baffle system.
 
#7 ·
I do a lot of efi conversions and aim for .125" between the nubs in the sock and the floor of the tray in the tank or tank bottom.
 
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