6.2 diesel vs. Gasoline considering dually

[cfan10]

Came across a cc dually w/6.2 190+ on odom turbo 400 auto trans, no bed, owner says he bought truck for flatbed. Body seems to be straight. Claims everything works. Decent inside, but he switched u joints from his truck. I am wondering what to look for w/diesel engines? Are diesels better than gasoline, or harder/expensive to fix? I try to fix most things myself. Thanks.
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[scotto0609]

I will give you my recent experience. I just purchased 2,the first is a 88 cc 6.2 dually 4wd,the second a 91 cc,454,dually,4wd.Both have @ the same 110k miles and are both are in ok condition. The diesel is fun to drive but slow compared to the gasser. So far the diesel is at @15mpg dont know about the gasser.The gasser cruises easily @70mph while the diesel is good for @ 60mph,mind you the 91 has a 4l80e,the diesel a turbo 400. So far the diesel has had a few quirks to work out but seems pretty straight forward,while I cant seem to get a cruise miss out of the gasser.Perfect world would probably be a 91 diesel with a overdrive! hope this helps. scott

[lindstromjd]

Depends on what you want to use it for, really. If you want a powerhouse for towing, then you'd be better off with a big block 454. If you want better fuel mileage, then the diesel is your friend. Think of it this way... a non-turbo 6.2 is ABOUT the same power curve as a TBI 305. A turbo'd 6.2 is about like a TBI 350. But, they get upper teens easily for fuel mileage with a TH400. Can't beat that at all with a gasser engine, especially not a big block.

There are a lot of good informative threads on here about what to look for with a 6.2 diesel. Search for them, and if you still have questions, then don't hesitate to ask.

[C-10 simplex]

Running a big block on the street = financial suicide.


regardless of towing ability.

[DetroitDan]

Originally Posted by C-10 simplex

Running a big block on the street = financial suicide.


regardless of towing ability.

so go buy a Prius

[DetroitDan]

Originally Posted by lindstromjd

Depends on what you want to use it for, really. If you want a powerhouse for towing, then you'd be better off with a big block 454. If you want better fuel mileage, then the diesel is your friend. Think of it this way... a non-turbo 6.2 is ABOUT the same power curve as a TBI 305. A turbo'd 6.2 is about like a TBI 350. But, they get upper teens easily for fuel mileage with a TH400. Can't beat that at all with a gasser engine, especially not a big block.

There are a lot of good informative threads on here about what to look for with a 6.2 diesel. Search for them, and if you still have questions, then don't hesitate to ask.

Very well said. The 6.2 is a good little motor in a light duty truck. Enough power for most normal tasks, just not a lot extra. And if you want to drive a little sporty, get something else, they are slow and not much fun. But, like anything else there's a tradeoff. They do get great mileage for their displacement, I've seen guys get way up into the 20s with 2wd half tons. They also stand up to abuse pretty well, long lasting and low maintenance. Lots of parts/parts trucks available, especially since the government bought a few million of them and retired them at 50k miles. But, keep in mind diesel is usually a little more expensive than gas, especially up here in the winter.

[rcbildr]

Originally Posted by lindstromjd

Depends on what you want to use it for, really. If you want a powerhouse for towing, then you'd be better off with a big block 454. If you want better fuel mileage, then the diesel is your friend. Think of it this way... a non-turbo 6.2 is ABOUT the same power curve as a TBI 305. A turbo'd 6.2 is about like a TBI 350. But, they get upper teens easily for fuel mileage with a TH400. Can't beat that at all with a gasser engine, especially not a big block.

There are a lot of good informative threads on here about what to look for with a 6.2 diesel. Search for them, and if you still have questions, then don't hesitate to ask.

X2

I have two vehicles with diesels and I love them. I don't care that they are not all that quick...that's why I bought an 83 Z28 and a 72 Ventura.

[GM72K10]

Originally Posted by lindstromjd

Depends on what you want to use it for, really. If you want a powerhouse for towing, then you'd be better off with a big block 454. If you want better fuel mileage, then the diesel is your friend. Think of it this way... a non-turbo 6.2 is ABOUT the same power curve as a TBI 305. A turbo'd 6.2 is about like a TBI 350. But, they get upper teens easily for fuel mileage with a TH400. Can't beat that at all with a gasser engine, especially not a big block.

There are a lot of good informative threads on here about what to look for with a 6.2 diesel. Search for them, and if you still have questions, then don't hesitate to ask.

X3. My son drives the CUCV to school, The diesel dually dump may not be quick but its better on fuel than my 06 K30. That is my "driver" when not using the new truck, They are good little engines those 6.2s.

[csa daddy]

plenty of torque just not fast at all but if ya like a good working diesel an aint in a hurry its one of the best an usually good for close to a million miles the turbo 400 is your only hold back there atleast as far as fuel mileage

[D13]

Go have a look
http://www.dieselplace.com/

I get 22MPG in my 87 1/2 ton, fully optioned. Most 305's get 16 or less.

I wouldn't tow with it. The bottom end is a little fragile (like to break cranks).

The 305 comment is right, but understand max RPM is around 3000RPM. Will it go 70MPH on the highway? Yes. Will it like it? No.

6.2's are great for guys like me, lots of easy miles commuting with few stops. They get great mileage and run for a long time, but when they need works, it's $$.

Assume that unless you know the truck and have a good idea on it's upkeep, within the first year you will have to replace the injection pump ($400), injectors ($275), glow plugs ($100 including solenoid override), fuel filter ($12). Be happily suprised if not so.
Next within 100K miles will be head studs ($190) and gaskets ($100 and a PITA in the truck if it has AC) oil cooler hoses if you tow at all ($? as they may need to be custom). Rubber crank pulley ($300 or replace it with steel ($50) if you like to tighten belts once a month) and balancer ($100 and make your own installer). Timing chain ($100) and water pump ($65) (BTW the water pump bolts on from BOTH directions, about 10 bolts. not a 15 minute job like on SBC).

For a 350, cap, rotor, coil, wires, plugs - $150. Aftermarket intake and carb - $500. In 100K miles, tune up ($150), timing chain, oil pump, gaskets ($100), water pump ($35). Any part you want available anywhere.

25-35% better fuel economy but 5% higher fuel prices (today).

Do the math on your situation to see if it works for you.

I love mine, will build another that should be trouble free for 200K. But I have spare trucks (gas) for when it's broken and the parts aren;t in stock (or simply aren't available any more).

[tucsonjwt]

I am intrigued by 6.2L fuel economy, but where I live diesel is 15-20% more expensive than gasoline. So, if a 350 can get 15 mpg city (I only drive city) a 6.2 would have to get 17.25-18 mpg city for the dollar equivalent per mile. Also, I have heard that the new low sulfur diesel is not good for old diesel engines? A rebuilt 6.2 seems to cost much more than a new crate or rebuilt 350.
I only drive my old 454 beater about 3,000 miles per year max, so the extra cost of a 6.2 diesel would not have an economic benefit for me. As a daily driver for 12 -15K miles per year I think it sounds like a good idea.

[STOCKISH]

But you can buy a low milt 6.2 CUCV engine on the web for $200-$800. My 6.2 is good to drive around on and gets good mileage. But I wouldnt tow much with it. Thats why it's coming out for a Cummins swap!

[tucsonjwt]

Originally Posted by C-10 simplex

Running a big block on the street = financial suicide.


regardless of towing ability.

I have had both 350 and 454 3/4 ton squares. Both got 10-12 mpg city, 13+ highway, and 1/2 tons might have been better by a couple mpg, assuming that they were in good mechanical shape. As I mentioned previously, modern V8s and V6s get 15-19 city.
Engine parts are more expensive for big blocks, but you normally don't replace engine parts - you replace all of the accessories which are about the same price. Of course, if you need a whole new engine (rebuilt or crate) then a big block is much more expensive.
It all depends on how you use your truck. If you use your truck infrequently for heavy hauling (like I do when hauling dirt, rock, etc. as a dump truck), then the extra horses in a 454 are nice to have.
I would not hesitate to buy a big block truck if it was in good shape. My 73 454/TH400 was probably the fastest vehicle I have owned, even though I did not buy it for that purpose. A 454 with a granny 4 speed (like my current truck) is a slow moving vehicle until you get into 4th gear, but it does have a lot of pulling power.

[lindstromjd]

Originally Posted by tucsonjwt

I am intrigued by 6.2L fuel economy, but where I live diesel is 15-20% more expensive than gasoline. So, if a 350 can get 15 mpg city (I only drive city) a 6.2 would have to get 17.25-18 mpg city for the dollar equivalent per mile. Also, I have heard that the new low sulfur diesel is not good for old diesel engines? A rebuilt 6.2 seems to cost much more than a new crate or rebuilt 350.
I only drive my old 454 beater about 3,000 miles per year max, so the extra cost of a 6.2 diesel would not have an economic benefit for me. As a daily driver for 12 -15K miles per year I think it sounds like a good idea.

Mine, with a TH350 and 3.40 rear end, got about 20 mpg's driving 20 miles a day with plenty of stop lights along the way. I just put a 700r4 in it, and haven't had a chance to drive it yet, but should be getting upwards of 24 mpg's with it now. The killer for fuel mileage in 6.2's is getting them moving from a dead stop. A TH400 is a huge horsepower thief, too. If you want better fuel mileage out of them, an SM465 works great because of the super low 1st gear, or the best option is an overdrive transmission like the 700r4.

Originally Posted by 1972SuperCheyenne

But you can buy a low milt 6.2 CUCV engine on the web for $200-$800. My 6.2 is good to drive around on and gets good mileage. But I wouldnt tow much with it. Thats why it's coming out for a Cummins swap!

6.2's are super easy to come by for really cheap (most people have NO respect for them at all). I've never paid more than $600 for one. The govliquidation site is a great resource for them, too. And military blocks are the best ones available because of the high nickel content.

[Edahall]

The power on these anemic 6.2's can be increased quite easily with some modifications. On my 1982 1/2 ton Suburban, the 6.2 was rated for 130 hp and it was painfully slow. I ended up installing exhaust headers, a free flow exhaust and J code intake manifold and it really woke the thing up. I tow a 26 ft Airstream weighing approximately 5000 lbs with it and it does well. I get 15 mpg towing the trailer and 30 mpg empty. I'm running a 3.08 rear end with a 700R4 automatic transmission so the engine rpm's run slow just where a diesel likes to run for good fuel economy. When towing, I tow in 3rd gear direct drive and the engine turns over at 1900 rpm which is right at maximum torque and it also saves the transmission. The 700R4 was never meant to pull hard in overdrive. I also add a small amount of 2 cycle oil to the fuel to bring back the lubrication that the Ultra Low Sulfur Diesel is missing. Anyways, what I like about my 6.2 L diesel is that it's a multipurpose vehicle and it doesn't break the bank in fuel costs.

[C-10 simplex]

Where to get these "cucv" (whatever that means) and who made these cucv engines? GM or are they copies?

[ghettoluxury]

The cucv is the military trucks built by GM. They were all 4x4 6.2 diesel with TH400 and were avalible in the blazer, long bed, dually bed, and cab & chassis.

[GM72K10]

Originally Posted by ghettoluxury

The cucv is the military trucks built by GM. They were all 4x4 6.2 diesel with TH400 and were avalible in the blazer, long bed, dually bed, and cab & chassis.

Commercial Utility Cargo Vehicle, an off the shelf "commercial" vehicle with some military adapted specs like the 24 volt starters and glow plug system, black out lights, etc. A civilian K30 diesel and a military diesel J code block are the same. Go to Steelsoldiers.com if you want to read up on these vehicles. Duallys were NEVER made from the factory for the military, they were made from a conversion kit out of either the M1031 SRW C & C or the M1028 or M1028a1 pickups. I have two of them at present. They are a lot easier to work on than everyone makes them out to be also.

[tucsonjwt]

Edahall - did you mean 30 mpg highway empty or 20 mpg? 30 mpg is pushing Prius territory.

[Edahall]

Originally Posted by tucsonjwt

Edahall - did you mean 30 mpg highway empty or 20 mpg? 30 mpg is pushing Prius territory.

Yes, I'm getting 30 mpg highway empty. I know of others with 6.2's who are getting similar mileage as well. In a nutshell, the formula for getting good fuel economy on these engines are high gearing, low resistance tires, small precombustion chambers, free flowing exhaust and being easy on the gas pedal.

[jeremy zander]

Just bought a 6.2 govt model CUCV 1008..1986 CHEVY K30..20MPG..not very fast..45-50mph tops...running new BFGs 285/75/16 tires