Author Topic: In Tank Pumps with Older Tanks  (Read 759 times)

Offline Doppleganger

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In Tank Pumps with Older Tanks
« on: November 26, 2018, 05:45:53 PM »
I've done some searching here and alot of reading but am still unsure about this.

I have an 85 K20 that I am converting to a TBI Vortec motor and 4L80e trans. I realize I will be going electric fuel pump - would rather an intank unit in each tank for redundancy. A friend of mine just told me of a shop nearby that will take the new tanks and cut holes in the top, then weld a collar for a 'factory fit'. 

Were the tanks different in 87 with TBI? Was just wondering if there is a 'factory' sending unit option that is what I need without cutting on new tanks. I also have 2 new sending units (for the carb setup) if those are of any use either. 

Sorry of this is a stupid or multi-asked question.....still getting up to speed on these things - been a couple decades since my last (carb'd) truck.
« Last Edit: November 26, 2018, 05:47:24 PM by Doppleganger »

Offline AZ4X4SQBDY

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Re: In Tank Pumps with Older Tanks
« Reply #1 on: November 26, 2018, 06:19:26 PM »
'87 tanks had baffles in them to prevent the fuel pump pick ups from being uncovered. Regular tanks will work, it's just suggested you keep more fuel in them as not to uncover the pick ups.

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Offline Doppleganger

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Re: In Tank Pumps with Older Tanks
« Reply #2 on: November 26, 2018, 11:49:35 PM »
Thanks for the reply.

Did my friend's mention of 'cutting a hole and welding in a collar for a factory application' make sense? Was just wondering what was different between my carb-esque sending units and a TBI one - I would think the TBI one (with an in tank pump?) would install in place of the regular carb'd one.

Thanks again.

Offline Silverado Clay

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Re: In Tank Pumps with Older Tanks
« Reply #3 on: November 27, 2018, 06:09:07 AM »
Thanks for the reply.

Did my friend's mention of 'cutting a hole and welding in a collar for a factory application' make sense? Was just wondering what was different between my carb-esque sending units and a TBI one - I would think the TBI one (with an in tank pump?) would install in place of the regular carb'd one.

Thanks again.
Im doing the same thing with my K20. I went to tanks Inc. and bother tank that has the fuel pump located inside. Im only going to use one tank due to the fact that the fuel return must go to the same tank that is being pumped out of. Making two tanks a switching/valve selecting nightmare, not to mention expensive.


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84 Silverado K20 4WD 350 TH400 NP208

Offline Doppleganger

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Re: In Tank Pumps with Older Tanks
« Reply #4 on: November 27, 2018, 05:51:59 PM »
I thought about that scenario also.

How did the 87's do it? AFAIK they still had the dual tanks, yes?

Online bd

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Offline VileZambonie

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Re: In Tank Pumps with Older Tanks
« Reply #6 on: November 27, 2018, 06:15:05 PM »
Thanks for the reply.

Did my friend's mention of 'cutting a hole and welding in a collar for a factory application' make sense? Was just wondering what was different between my carb-esque sending units and a TBI one - I would think the TBI one (with an in tank pump?) would install in place of the regular carb'd one.

Thanks again.

Not sure why your friend is suggesting any modifications are needed. 87 tanks are baffled, 73-86 tanks work as well just keep the fuel level adequate, 1/4 tank is fine for inclines. The factory routing works fine and there is no reason you would need to eliminate dual tanks when going to EFI. http://forum.73-87chevytrucks.com/smforum/index.php?topic=9072.0
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Offline Doppleganger

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Re: In Tank Pumps with Older Tanks
« Reply #7 on: November 27, 2018, 07:25:05 PM »
Thanks for the links fellas - good stuff there. For no other reason than I can be anal retentive (and I've got time), I may peddle my new Spectra tanks and get the baffled ones for an 87.

The friend that suggested the holes is basically a Dodge guy so he's used to having holes all over his truck.......although most appeared naturally after the first rain.   :D

Offline 75gmck25

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Re: In Tank Pumps with Older Tanks
« Reply #8 on: November 28, 2018, 07:34:00 AM »
You can also get a direct replacement high pressure fuel pump to mount in the older tank, and then use a Holley Hydramat instead of adding baffles.  The Hydramat is made of special material that works like an in-tank baffle, but its collapsible enough that you can stick it in through the sending unit hole.  Just be prepared for sticker shock, since Hydramat is not cheap.

Bruce

Offline Doppleganger

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Re: In Tank Pumps with Older Tanks
« Reply #9 on: November 28, 2018, 08:26:51 AM »
I'll definitely look into that Hydramat - thanks for that.

Does the HP fuel pumps mount to the older style sending unit or does it replace it? Of course.....I have 2 brand new (older style) sending units also.   ::)   

Offline hatzie

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Re: In Tank Pumps with Older Tanks
« Reply #10 on: November 28, 2018, 12:00:13 PM »
Thanks for the reply.

Did my friend's mention of 'cutting a hole and welding in a collar for a factory application' make sense? Was just wondering what was different between my carb-esque sending units and a TBI one - I would think the TBI one (with an in tank pump?) would install in place of the regular carb'd one.

Thanks again.
I’m doing the same thing with my K20. I went to tanks Inc. and bother tank that has the fuel pump located inside. I’m only going to use one tank due to the fact that the fuel return must go to the same tank that is being pumped out of. Making two tanks a switching/valve selecting nightmare, not to mention expensive.


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Retrofitting NL2 dual tanks with TBI or Fuel Injection that doesn't use more than 65psi isn't horribly expensive or nasty to do.
The Factory NL2 dual tanks with TBI is not oogie boogie.  It's really quite simple.  http://forum.73-87chevytrucks.com/smforum/index.php?topic=37007.0
You need the NL2 harness from an 87-91 TBI truck. You can roll your own GM reproduction for under $75 in parts or pay for one used or new.
You need the Pollack valve @ $65 and Switch $15
You need one more 1987 gas tank and both supports. @ $150.
You need the TBI senders with fuel pumps.  $100 $150 each


« Last Edit: November 28, 2018, 12:20:29 PM by hatzie »
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Offline Doppleganger

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Re: In Tank Pumps with Older Tanks
« Reply #11 on: November 28, 2018, 02:22:26 PM »
Wow. Lots to wrap my empty head around. Seems almost easier to buy a rotted 87 for parts and cheat sheet usage.

Thanks much for the links.

Offline VileZambonie

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Re: In Tank Pumps with Older Tanks
« Reply #12 on: November 28, 2018, 06:58:46 PM »
It's amazingly good information which will help you. You are not expected to memorize it but to utilize it. Do not be overwhelmed as it's actually quite a simple design.
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Offline roundhouse

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Re: In Tank Pumps with Older Tanks
« Reply #13 on: November 28, 2018, 08:21:26 PM »
I got an 87 tank with the tbi pump  from rock auto

Using dual tanks with return lines is. Not hard
Lots of pickups had that
The switching valve just has six ports instead of three