Lets give the 6.2 diesel some love

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1983 k20

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I'm not sure if this applies to engine and performance , but I'm sick of people saying that the 6-2 is junk . So I'm going to stand up for this old diesel. It has many benefits over the 6.9 idi and 5.9 cummins .
Its setup is great for pulling with peak torque at 2200 rpm . Just keep in mind I'm a new guy here
 

Grit dog

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Welcome to the forum Hayden!
See you have the venerable 350 in your truck. Why no 6.2? LOL
I'd like to hear of it's many benefits over the 5.9. Double lol.
BTW, I've had snomachines with way more HP!

I agree though, that stump pulling 100hp and 240ft lbs of tq at 2200rpms was a force to be reckoned with! Triple lol.
 

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On a different note, they were great for fuel mileage back in the day compared to the gas guzzlers and those engines paved the way for the awesome power diesels we have today.

Just like early EFI systems. While some were a bit problematic, those early systems are why we have such bulletproof and efficient EFI systems now.
 

Grit dog

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I will say they seemed pretty reliable though. We had 1 6.2 diesel in the fleet that I maintained back in high school. I knew nothing about diesels and actually dreaded the day it would have fuel or engine issues and to my recollection it never did while I was there.
It was also the LAST truck to leave the yard for ANYTHING. Guys would take our little Nissan pickup before that 6.2 unless the load wouldn't physically fit in it. They'd use an old Ramcharger with a 318 to tow with before that truck as well.
Maybe why it didn't break down. Wasn't used much! I liked to drive it if I wasn't in a hurry, because it was the nicest condition truck in the fleet....because no one drove it!
 

Ricko1966

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Well a few benefits of the 6.2. 1. It bolts right into your square with no mods 2. It gets great mpg. 3.they're dirt cheap. 4. They're so simple a four year old can hook them up 5. They'll tow anything and not complain. I bought one for my 75 K10 paid 600.00 for the whole g van with 70,000 on it and drive it home.
 

Bextreme04

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Well ,they are simple and last forever... other than that I can't think of a single reason to have one. After working on them in the army in HMMWV's.....not a fan

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1983 k20

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I do have much experience with 6-2's despite the fact I have a 350. My grandparents and my dad both have 6.2 diesel's. 1 of my Grandpas is a 87 k30 .it has unbelievable power because of the setup . Its useless when torque is a 1600 rpm like the 6.9 diesel
 

Bextreme04

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I do have much experience with 6-2's despite the fact I have a 350. My grandparents and my dad both have 6.2 diesel's. 1 of my Grandpas is a 87 k30 .it has unbelievable power because of the setup . Its useless when torque is a 1600 rpm like the 6.9 diesel

I mean... the 6.2L is the weakest engine you could get in a K30(actually a V30 in 87). The 350 had 40 more horsepower and 50 more lb-ft of torque, and it was only 400rpm higher in the powerband. The 454 had 80 more HP at the same RPM and 140 more lb-ft of torque at 400rpm LESS than the 6.2L. And that is one of the weakest 454's ever put in a GM. And the torque curve on that 454 is basically a flat line. I would bet that at no point in the range from 1000-5500rpm does it make less than the peak torque of that 6.2L.

About the only benefit I can think of to a 6.2L is fuel mileage, a 454 will pass anything out there except a gas station. My 350 doesn't do much better in that regard.
 

1983 k20

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But what's the point of peak torque at 1800 rpm a Cummins needs 2000 rpm in 6th gear to maintain hiway speeds . I know you said it is a flat line on a 454 .
We haul firewood with the k30 . Easily 2 cords on the flat deck ( note that we have no performance upgrades on it ) and we live in a hilly country. All we do coming up a steep hill is drop it to 3rd and that's it .
 

75Monza

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My ol' 6.2 ran good for the most part till pump and injectors wore out from low sulfur diesel. Was pretty gutless though, even with 4.10's and TH400 in my burb, with just 35's on it, most passes were about 45 mph. The killer on those was having the CR at 21.5:1 and being non-turbo, head design could barely take it. Plop it in a C10 with a 5 speed or 700r4 and got fuel mileage you could smile at for a truck. Glow plug system really sucked too, was always changing a plug out and lost the controller about every 3 years seems like. \
Life was sooooo much nicer when I gave the 6.2 to my friend and dropped in a 6.5 with around 18:1 CR, a banks sidewinder kit and intercooler, then had a 4 piston pump and Hi-pop injectors to go with it....I could do locker burn outs afterwards, got better mileage and never dropped a gear on summits again. Don't remember the boost, was fairly low around 15-18, had to watch EGT or cause a melt-down. Still, think it dyno-ed around 240hp+ and 480ish torque.
 

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I bought the g30 in Columbia Missouri.Drove it back 99 percent highway.6.2 4l80e and I got right around 25 mpg. Don't remember because it's been years ago but I think it was straight up 25 mpg.In a huge box on the highway definitely not the fastest thing on the road but didn't feel any worse than a 350 for drivable power not as quick but definitely better mpg and pulling capability.And I don't like diesels, but they have their place.Something affordable to pull heavy trailers and have enough money for fuel and lunch. I live 60 miles round trip minimum from anywhere, and usually most places I need to go are considerably farther.So a 350 pulling a trailer getting 8mpg or a 6.2 pulling a trailer and getting 20 it's a big difference. Hell empty with a warmed up 350 square I'll burn 18.00 worth of fuel to go get a burger. Or I can burn 9.00 worth and take a couple more minutes getting there.And I hate diesels.
 
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Blue Ox

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I'd like to hear of it's many benefits over the 5.9. Double lol.

1) The sound. The 6.2L is about the best sounding of any of the big 3's engines. A 5.9L Cummins sounds like a bucket of bolts down the intake.

2) 8 cylinders. Much smoother power that won't rattle your truck apart.

3) Four cylinders long. Fits much better under the hood than an inline six.

4) Remember you have to take these things in the context of the time. Most of the offerings for engines were pretty wimpy as well. I'll put my 6.2L up against any engine offered in the same model year except the big block. Obviously they're not in the same class, but as stated, burns gas like there's still dinosaurs walking around.
 

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Besides @Blue Ox, I didn't think we had any 6.2 fans here.

Looks like you made yourself a new buddy

:love62:


Guess what else bolts directly in squarebodies?

Big blocks. :jester:


You know how much torque my big block makes at 2500 rpms?
Roughly 500 ft lbs.
It ALSO makes higher torque at 4800 rpms.

Passsssssssssss :p


OK kidding (not about the numbers)


The 6.2 isn't really THAT bad.
I actually admire its noisy, mechanical, clanky idle.... Pretty cool old diesel.

Had on old k10 with a 4 speed auto, 208, and 6.2


Man she jerked your neck in low 4x4.

I tried to actually obtain my old diesel k10 and buy it back.... Owner sold it to someone else :(
 
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Ricko1966

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Besides @Blue Ox, I didn't think we had any 6.2 fans here.

Looks like you made yourself a new buddy

:love62:


Guess what else bolts directly in squarebodies?

Big blocks. :jester:


You know how much torque my big block makes at 2500 rpms?
Roughly 500 ft lbs.

Passsssssssssss :p


OK kidding (not about the numbers)


The 6.2 isn't really THAT bad.
I actually admire its noisy, mechanical, clanky idle.... Pretty cool old diesel.

Had on old k10 with a 4 speed auto, 208, and 6.2


Man she jerked your neck in low 4x4

I've got a couple of big blocks too, but as I said 18.00 in fuel to get a burger with a 350 now it's 30.00 with a big block. Or 90.00 in fuel to go to the machine shop and back. Gotta pick and choose that's why I have different cars and trucks for different uses.
 

Bextreme04

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But what's the point of peak torque at 1800 rpm a Cummins needs 2000 rpm in 6th gear to maintain hiway speeds . I know you said it is a flat line on a 454 .
We haul firewood with the k30 . Easily 2 cords on the flat deck ( note that we have no performance upgrades on it ) and we live in a hilly country. All we do coming up a steep hill is drop it to 3rd and that's it .

Torque gets you moving... HP keeps it moving. Here's dyno sheets for a TBI 454 and a 6.2L diesel. Like I said, there is no comparison if you want shear towing ability. If you want diesel sound and fuel mileage... yes, if you want power... no. Like others have said, they have a following and fill a gap where people want to be able to tow light loads while getting good mileage. But if I was trying to tow with a diesel it would have to be at least a turbo 6.5. Driving the old HMMWV's compared to a new up-armor with a 6.5 Turbo and 4L80E is no comparison. The new ones will blow the doors off the old ones, even with a Gross weight up near 12,000lbs from all the armor add-ons. You couldn't give me a 6.2.

Mine is a 350, and it has no problem pulling heavy loads. 350/TH400 with 4.10's and 35's has easily pulled 4,000lbs of logs or 3/4" minus through the cascades like it isn't even in the back. Of course, that's at about 55mph with no need to drop any gears since it's wound up pretty high at that point. I'm assuming with the "drop it into 3rd" comment you have a 700R4 in it? I think that was standard for the diesels, right?

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