Can’t decide on single or dual tanks

[boltbrain]

Well, Montana is a big state. Especially if you're driving a gas sucking 40 year old truck around. Take a half tank just to get to the grocery store in most places!
The move the truck to fill the other tank argument is almost a moot point, considering many gas stations are set up to fill either side, long enough hose and no issue with dragging the hose across with a flatbed.
The safety issue is moot as well, IMO.
That said, the Blazer tank is a simple troublefree solution and there's no hidden reasons to keep the dual tanks in the OE location.
31 gal vs 40. But 71 gal sounds really cool! (If you are actually piling on the miles and long drives)
Or if you have one good saddle tank, and you already have the rear tank, a dual tank setup for 51 gal is an option as well.

I am considering putting the good side tank in. It would really come in handy. I also like the tank to tank pump idea. To keep it simple.

 

[boltbrain]

My first truck, many years ago, was a 79 K10. It had dual tanks, which I thought was a cool feature at the time.
This was before pay at the pump and debit cards, so filling both tanks meant the clerk was inside, phone in hand, ready to call 911 every time I left the pump to fill the other side. Or I had to go in, guess the amount and pay cash up front.
Anyway, it was a Christmas eve and I was driving my wife 300 miles to see her parents. No issues on the way up. Coming back the next evening, in a blizzard, I went to switch tanks. Uh oh, the switchie no workie. The switching valve, whether frozen or junk, had failed. 16 gallons of fuel @ 10mpg= less than 300 miles. Back then, on Christmas Day night, most gas stations were closed.
Me, not being as dumb as I look, had two 5 gallon jugs of fuel in the bed for just such an event.
I currently have an 80 K15 with dual tanks under restoration now. My druthers are to keep and run on one tank until I figure out a larger one tank solution.

The 40 gallon wouldn’t fit where I put my 31. But I’m pretty sure it would fit in the rear using the mounts it had in the burb. That’s much easier than what I did.

 

[Grit dog]

I also like the tank to tank pump idea. To keep it simple.

Not a huge fan of "secret" features on vehicles, especially those that have the ability or propensity to be operated incorrectly.

Of course, may folks are of the "It's MY vehicle and I'm the ONLY one who drives it" mindset. That's all well and good until you aren't the person driving it, or get distracted from your usual routine.
I can think of several things that could happen while you're happily plugging along and transferring gas from one tank to the other that would result in remembering to shut off the pump being forgotten until gas was spilling out of the filler.

By the same token, how much simpler does it get than the OE fuel tank switching valve? Would work just fine, exactly the same with a side and rear tank. And the replacement valve/solenoid isn't exactly cost prohibitive.
Of course I always think resale and/or purchasing. The 2 biggest turnoffs besides rust in an old vehicle is someone's Ray Charles idea of a "good" paint job/multiple coats of repaint and a bunch of Busch Light inspired "improvements."

JMO, not my truck though.

 

[boltbrain]

Well, Montana is a big state. Especially if you're driving a gas sucking 40 year old truck around. Take a half tank just to get to the grocery store in most places!
The move the truck to fill the other tank argument is almost a moot point, considering many gas stations are set up to fill either side, long enough hose and no issue with dragging the hose across with a flatbed.
The safety issue is moot as well, IMO.
That said, the Blazer tank is a simple troublefree solution and there's no hidden reasons to keep the dual tanks in the OE location.
31 gal vs 40. But 71 gal sounds really cool! (If you are actually piling on the miles and long drives)
Or if you have one good saddle tank, and you already have the rear tank, a dual tank setup for 51 gal is an option as well.

I did a search and found on two sources that a 2002 Chevy 2500 4x4 with a 6.0 liter LS in it gets 11 mpg highway. About the same as my 79 3/4 ton 4x4 that has no overdrive, 4:10 gears, and 30” tires. So I’m at a total loss as to why I keep seeing reference to “ 40 year old gas sucking” The 2002 Chevy 1500 two wheel drive with 4.3 LS gets 18. But that’s not comparing apples to apples.

 

[boltbrain]

Not a huge fan of "secret" features on vehicles, especially those that have the ability or propensity to be operated incorrectly.

Of course, may folks are of the "It's MY vehicle and I'm the ONLY one who drives it" mindset. That's all well and good until you aren't the person driving it, or get distracted from your usual routine.
I can think of several things that could happen while you're happily plugging along and transferring gas from one tank to the other that would result in remembering to shut off the pump being forgotten until gas was spilling out of the filler.

By the same token, how much simpler does it get than the OE fuel tank switching valve? Would work just fine, exactly the same with a side and rear tank. And the replacement valve/solenoid isn't exactly cost prohibitive.
Of course I always think resale and/or purchasing. The 2 biggest turnoffs besides rust in an old vehicle is someone's Ray Charles idea of a "good" paint job/multiple coats of repaint and a bunch of Busch Light inspired "improvements."

JMO, not my truck though.

You’re forgetting about the solenoid’s electrical features. Maybe not that difficult to install but troubleshooting things in the dark, beyond any sign of civilization, where the nearest AAA is 300 miles away, with the road turning into a snowdrift while its 30 below zero is something I try to avoid. Simplicity is what I want first and foremost, always. Resale is the least of my worries.

 

[Grit dog]

Because they are? A gmt800 6.0 will get 11mpg doing 80mph plus all day long and has almost twice as much power as a 70s/80s stock 350.
11mpg in your truck is pretending that "55 saves lives". Your truck is doing 2500-3000rpms to run 55-65mph. At 55-60mph that 6.0 is knocking down 15mpg on the highway.

And the 4.3 is much closer to apples to apples, since it only makes about 45hp more than a 1979 350, lol.

 

[boltbrain]

You’re forgetting about the solenoid’s electrical features. Maybe not that difficult to install but troubleshooting things in the dark, beyond any sign of civilization, where the nearest AAA is 300 miles away, with the road turning into a snowdrift while its 30 below zero is something I try to avoid. Simplicity is what I want first and foremost, always. Resale is the least of my worries.

No, the solenoid would not have to work exactly the same with any two tanks, because you wouldn’t need a solenoid. The fuel shutoff solenoids in diesels fail all the time, but a simple hand operated cable can substitute. I’ve done it in cummins 12 valves. Lots of guys have. I can find a cable operated solenoid or I can have two tanks with a pump between them. Yes the guesswork has to be eliminated to pump tank to tank, so add a fuel gauge and don’t pump out the 20 gallon until the 31 gallon is near empty. Nothing the Busch inebriated can’t handle.

 

[Grit dog]

You’re forgetting about the solenoid’s electrical features. Maybe not that difficult to install but troubleshooting things in the dark, beyond any sign of civilization, where the nearest AAA is 300 miles away, with the road turning into a snowdrift while its 30 below zero is something I try to avoid. Simplicity is what I want first and foremost, always. Resale is the least of my worries.

Not really. Yes, half the tank valves or more are probably currently failed or about to. Because they're 35-50 years old, or maybe replaced "only" 20 years ago.
They're not inherently unreliable (although the ones that remain energized to stay on one tank or the other are not the greatest design admittedly).
I wouldn't inherently put more trust in a homemade transfer setup with a little puddle sucker fuel pump. Nor would I necessarily trust it less, doesn't feel simpler though, just different but with the potential to dump your fuel on the ground.

It's all good though, JMO and not my truck like I said before. No offense meant.

But just so you can make me jealous, what part of MT are ya from?

 

[boltbrain]

Because they are? A gmt800 6.0 will get 11mpg doing 80mph plus all day long and has almost twice as much power as a 70s/80s stock 350.
11mpg in your truck is pretending that "55 saves lives". Your truck is doing 2500-3000rpms to run 55-65mph. At 55-60mph that 6.0 is knocking down 15mpg on the highway.

And the 4.3 is much closer to apples to apples, since it only makes about 45hp more than a 1979 350, lol.

Ok well I’m learning about chev is now. So you’re saying I can put a 4.3 in this 79 and get better mileage and 45 more hp? I had no idea.

 

[boltbrain]

Not really. Yes, half the tank valves or more are probably currently failed or about to. Because they're 35-50 years old, or maybe replaced "only" 20 years ago.
They're not inherently unreliable (although the ones that remain energized to stay on one tank or the other are not the greatest design admittedly).
I wouldn't inherently put more trust in a homemade transfer setup with a little puddle sucker fuel pump. Nor would I necessarily trust it less, doesn't feel simpler though, just different but with the potential to dump your fuel on the ground.

It's all good though, JMO and not my truck like I said before. No offense meant.

But just so you can make me jealous, what part of MT are ya from?

No offense taken. It just occurred to me though that when you go to one big tank and a smaller tank, what’s probly gonna happen in real life is you use the big one most all the time except for long trips, and have the other one sitting there empty like a potential bomb. Because it’s the fumes that explode. So I’ll just stick to what I have and take a Jerry can on my long trips.

 

[Grit dog]

Ok well I’m learning about chev is now. So you’re saying I can put a 4.3 in this 79 and get better mileage and 45 more hp? I had no idea.

To qualify, there are 2 4.3 engine configurations. The latter being LS based, starting in 2014. Those are 280 or 300hp (not as much torque as a 300hp V8, but...) and they just dropped that engine last year or the year before in favor of only offering the turbo 4 banger as the "base" engine in full size GM trucks.

But the original 4.3s are literally 3/4ths of a 350 small block, same bellhousing, same motor mount locations. Those started out in the mid 80s in S10s and squarebodys. They were pretty milqutoast, bout the same HP as a late 70s 350 prolly with less torque. But they remained long after the small block got phased out for the LS platform V8s.
They started as carbed engines in mid 80s, to TBI late 80s early 90s, then cfi then mpi with Vortec heads. Gm always kept them right about 200hp output even with the improvements (except the Syclone and Typhoon motors).

Yes I'd say you could get better mpg if you could drop in a Vortec "old style" 4.3, even maybe a TBI (little better at metering fuel than a carb). But the biggest killer of mpg on your truck (and our 86) is the deep gears and no OD. You wont get good mileage at Montana highway speeds with anything with gearing meant to pull a house slowly, rather than propel a truck at high speeds.

 

[boltbrain]

To qualify, there are 2 4.3 engine configurations. The latter being LS based, starting in 2014. Those are 280 or 300hp (not as much torque as a 300hp V8, but...) and they just dropped that engine last year or the year before in favor of only offering the turbo 4 banger as the "base" engine in full size GM trucks.

But the original 4.3s are literally 3/4ths of a 350 small block, same bellhousing, same motor mount locations. Those started out in the mid 80s in S10s and squarebodys. They were pretty milqutoast, bout the same HP as a late 70s 350 prolly with less torque. But they remained long after the small block got phased out for the LS platform V8s.
They started as carbed engines in mid 80s, to TBI late 80s early 90s, then cfi then mpi with Vortec heads. Gm always kept them right about 200hp output even with the improvements (except the Syclone and Typhoon motors).

Yes I'd say you could get better mpg if you could drop in a Vortec "old style" 4.3, even maybe a TBI (little better at metering fuel than a carb). But the biggest killer of mpg on your truck (and our 86) is the deep gears and no OD. You wont get good mileage at Montana highway speeds with anything with gearing meant to pull a house slowly, rather than propel a truck at high speeds.

I know I need overdrive, just don’t know which engine to look for. Or which engine/tranny combo, that is. I need lots of torque. Not that worried about mileage, but it’s preferred. I like to blast throo snow drifts with four chained wheels. And I’m tired of trying to start diesels below zero. How torky is the 6.0 and is it harder to swap in because of it’s size?

 

[Grit dog]

^ Ha! I like how you think! 6.0 is the same size physically as the 5.3 and 4.8. Dimensionally I believe all LS engines are the same. But I’m sure there’s some nuances that the guys with ls swap experience know. But swapping 6.0 Engines is pretty common in squares.
You don’t want an old small block 4.3 if you want torque.

 

[SirRobyn0]

I'm coming along a little late but still want to give my input on 2 tanks vs one rear mounted tank. I had to cross this bridge a few years ago.

My truck was a factory single tank, and had developed a leak. I was not happy with one 20 gallon tank, I mean unless you hammer the tank on E there is what about 15 usable gallons. That's something like 200 miles on a good day on the highway and less than 150 on a bad day with a loaded trailer even less. That was totally unacceptable when making a couple hundred mile journey for feed. In the end I decided to add a second 20 gallon side saddle tank. Main reasons were I felt that the two side saddle tanks spread the weight out better, it was an simpler install, and nets me a total of 40 gallons. I start with two full tanks hammering the left tank on E knowing that the right is full, plus run that to a 1/4 I've got a solid 35 usable gallons. That's about 450 miles on a good day 350 on a bad day. I'm not disparaging the the rear tank swap at all I came close it and there are good reasons for doing it. But in the end I just didn't feel that the work involved was worth while to gain 11 gallons, where as I could bolt on stock components to gain 20 gallons and get 40 gallons total.

The switching valve for a two or even if a guy wanted a 3 tank system, is not really an issue anymore. In the old days there were units, particularly the one wire valves that were prone to failure. The newer units produced by Pollak and often sold under the brand Wells is very reliable. Far more reliable than any electric transfer pump could be. Keep in mind we are dealing with fuel here, and if I guy home brews a transfer tank system and there is a large amount of fuel spilled or fire involved you could be on the hook for the clean up / damages.

Like @Grit dog said a 35 - 40 year old, or even 20 year old replacement valve fails and guys get all upset about reliability. Show me an aftermarket electric fuel pump (frame rail type not injection) or electric transfer pump that age that still functions. It's just like the guys that whine and complain about there rubber fuel lines breaking down from ethanol. Yea, all know ethanol if hard on rubber fuel lines but after 35 - 50 years those lines are shot from age! I'm just saying. At least with the switch valve a guy could lay under the truck and swap ports on the valve to manually change the tanks. With an electric transfer pump if it goes bad your out of luck. Just my opinion obviously but maybe some food for thought on that subject.

 

[Finkaire]

I ordered mine with the single tank, didn’t know it was 16 gallons. No long trips without having to fill up. In the GM settlement I got $1000 towards my Suburban.