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Is the 6.2 turbo diesel really that bad???

116K views 69 replies 33 participants last post by  dragogt 
#1 ·
I have a 7.3 Powerstroke that I absolutely love. It's too big and heavy to trail with, so I've been thinking about a military 6.2 Blazer. Mild lift, 33-35s, lockers, and a turbo.

I know it's not going to be fast, but wouldn't it still be good for the trails and "some" driving around town? One thing I would like to do is swap the auto for a 5-speed manual. Is there a tranny that would bolt up?

I hear a lot of really bad things about the 6.2/6.5, but I've also read that it's really not "that" bad. Diesel Power Mag did a spread on it and they didn't trash it too bad. They did say that it's never going to make a ton of power, but it can be reliable and is an easy swap, being that it's basically the same size of a SBC.

Anyway, any opinions are welcome.

Steve
 
#3 ·
I'm still daily-driving my non-turbo 6.2, and it has never once embarrassed me, or made me angry at it. 130 HP isn't a lot, but it moves very well. Especially from a dead stop. I've seen 28 MPG in the current configuration, too. My 6.2 came from an '83 C-10, I stuck it in a '79 C-20, along with a 700R-4 trans, custom wiring for the converter lockup, Hooker 2.25" dual mandrel-bent exhaust, 4.10:1 axle, LT265/75R16x8 rear, LT235/85R16x6 front, 5" front airdam, age-sagged springs, AIS dual-snorkel, and a Camaro torque converter. I checked MPG at a steady 55 MPH.
Banks offers a turbo kit, and I don't believe it would hurt durability / reliability. If you want to go the low-cost route of a salvaged turbo setup from a 6.5, then your results may vary.
 
#4 ·
I've seen 28 MPG in the current configuration, too.

Camaro torque converter. I checked MPG at a steady 55 MPH.
No you haven't, and i think the last time you told this lie it was a Corvette converter....

The 6.2's will live forever if treated right, they have some dumb quirks, but once you work through them, they are tolerable. Back in the day, I had a 2wd half ton with a 6.2, and north of 250k on it, it was a rattly smoky smelly bastard, but it still ran ok. I tink I would prefer a gasser trail only rig just for pure simplicity, and cheap parts.

For the record, my 6.2 was in a lowered truck with a 700r4 and 3.xx gears and never busted much over 20....
 
#5 ·
They are about the same size as a CBB.. All the trannys with standard GM bellhousing will bolt up.. I think the 6,2D with a SM465 - NP205 is a nice combo.. Its only 4 speed, with a granny low 1'st gear:D
6,2D is a nice engine, just make sure the injectionpump, injectors
and the glowplugs are good.. They sound pretty good with a little more open exhaust to
 
#16 ·
I had an 84 diesel Suburban. TH400 and 4.10. I changed to SM465 and 3.21 14bFF axle to make it tolerable as a DD. Went from 10-12mpg to 17. It was still loose and rattly... probably why it smashed a clutch disc.

So in your diesel K5 Blazer dream, I see at a minimum:
- overhaul the engine
- add a turbo
- rear axle upgrade
- re-match axle ratios and wheel bolt patterns
- trans swap

OTOH, you could find yourself a 1st-gen CTD and jam its guts into Bronco, K5, or RC and call it done.
 
#17 ·
i drive a 88 3500drw 4x4 with the 6.2 350000 kilometers on it. the truck runs well for its age i will replace it as soon as finances allow. after all it is over 30 years old.
I would replace the harmonic dampener asap most of the old engines that i see at the wreckers have a broken crank
second would replace the injectors
 
#18 ·
Thanks guys for the honest opinions. I don't get why the fuel economy war started. I wouldn't be getting this truck for the fuel economy. I want it because of the torque, and to be different.

So, let me ask you guys an honest question. What would you rather have.

A 6.2 Blazer, or a 99 F250 extended cab, long bed. Like I said before, I love my truck and would love to have an excuse to put a 4" lift and 35's on it. I love the torque of 4 low in granny gear.

From what I have figured, if I can put the money I'd be spending on a Blazer, and have a lift and tires for my truck. That'll give me a great truck that's probably fairly capable, but it's long. I just don't have enough wheeling experience to know if it's pointless to try to hit the trails with a truck the size of mine.

As far as the Blazer goes, maybe I'm giving that engine more credit than it deserves. Here's a video of my truck, in 2wd low (hubs unlocked), granny gear, and standing on the brakes. The engine doesn't even load up at idle. Then if I step on it, I've got 600 ft/lbs of tq to the wheels.

7.3L Powerstroke torque at idle - YouTube
 
#19 ·
My OPINION on the 6.2 is...

-Its not necessarily a "bad" motor, just not a good one.

-It lacks balls.

-It is a diesel, as well as heavy.

-Like almost any other engine, a well taken care of one will last you a looong time. One thats been ragged (pretty much anything military driven), I would not have such expectations from.

-That said, I would go for a K30 with a 6.2 instead of the blazer, simply because the K30 already comes with the D60/14ff with 4.56's and a detroit in the back VS the ten bolts the blazers got. Plus, I like to have a bed to throw my shit in. I would also proceed to beat the living piss out of the 6.2 until it flat ass quit life all together, and then Id drop a bbc in it, and proceed on with my funhaving behavior. :D
 
#29 ·
ok so what's your point? a link to another worthless thread of some guys telling the truth, and others bullshitting on thier mileage claims? let it go already.
 
#28 ·
I have a 84 m1009 engines all stock i have only had it out 3-4 times and its done fine for me. just depends on the type of terrain you run, biggest down fall is places where high rpm comes to play like mud it didnt take long for me to find the 3800 govener !!! I dont know about mpg but on a two day offroad trip i may have burned a wopping 2.5 gals of fuel estimated. replace glow plugs and double check all fuel lines relace all questionable lines and maybe swap to spin on fuel filter and will be fine.
 
#30 ·
I have a 84 m1009 engines all stock i have only had it out 3-4 times and its done fine for me. just depends on the type of terrain you run, biggest down fall is places where high rpm comes to play like mud it didnt take long for me to find the 3800 govener !!! I dont know about mpg but on a two day offroad trip i may have burned a wopping 2.5 gals of fuel estimated. replace glow plugs and double check all fuel lines relace all questionable lines and maybe swap to spin on fuel filter and will be fine.
 
#31 ·
im like a very irritable grumpy old fart (no offence to grumpy old fart) but ive driven a few of of those 6.2s and i know diesels are supposed to be a bit noisey but i get a headache in those things within 10 minutes, all that vibrating, tinging and banging drives me crazy. im a full exhaust gas engine kinda guy so make sure youre not as easily annoyed as me before committing to one of these engines.

i always joke with the guy next door at my work that has the 1008 military pick up that the government knew they were slow as hell thats why they put 4.56 gears in them
 
#33 ·
OK, the 6.2 is out of the question. The military trucks can be had for about $3K. Then the Banks turbo is another $2K. So, after $5K, I still don't have much. I'd much rather get a mid 90's Powerstroke.


I honestly think I'm going to put a mild lift on my truck, with 35's. Right now I've got 32's with a stock off road package suspension, which is high in the back. If I lift the front 4", and the rear 2", that'll level it out and probably be plenty of lift for what I want.

Then throw a locker or two into it, then I'll have something that's still my DD, my tow rig, and something that I can hit the trails with once in a while.

Anyway, thanks for everyone's help and opinions.
 
#38 ·
Its your truck, and do what you want. Some of us are simply giving sound advice.

Im not going to spoonfeed you wheelbase numbers. Truth be told, this belongs in the Newbie Forum, and if you had searched, the numbers alone would have given you the answer you seek.

Rule #1- DONT WHEEL THE TOW RIG/DD. Why? Because after you break shit Friday night, or Saturday, that rushing on Sunday to slap shit back together brings the SUCK.

Im not following why anyone would spend 2k on the banks turbo kit, or even spend time swapping some 6.5 stuff onto the 6.2. To me, the money is better spent building a nice small block (you can build a pretty sweet sbc for 2k) or even overhauling a bbc to shove in there after you pop the 6.2. I would go gasser for higher rpm's simply to suit my style of wheeling.

For the same price, you could get a F350 7.3 powerstroke, which I would prefer personally if I HAD to drive a Ford. They are pretty stout motors, with a 5 speed, and arguably equally strong axles as a K30, and a decent amount of aftermarket support. It all comes down to personal preference.
 
#41 ·
Big difference between a ragged out ex-military Blazer with no carpet or insulation and a good running civvy version. I've owned a '90 K5 6.2 since '94. With stock exhaust it was very quiet inside and out and I made many multi-hour road trips in it and none of the passengers every even commented on interior noise. Even with dual glasspacks on it my now-wife never mentioned anything, yet everytime she rides in my 2500HD 6.0L truck with, in my opinion, rather quiet Dynomax mufflers she comments on how loud it is.

With 32" mud tires and an 18 year old behind the wheel I consistently hit 18 mpg with mostly city and country road driving, always being at WOT (waiting for the comments here), and always speeding (got a couple tickets going 80+ on the highway).......point being about the absolute worst driving when it comes to good fuel mileage. I'm sure if I had half-way tried it would have gotten low-20s.

Is it the best engine ever....not even close. Have I been happy enough with it from daily driving to the current off-road only rig with 40" tires, 1-ton, and dual lockers where a different engine is low on the list....yes. When the 6.2 needs replaced I will have to think hard about what to do.

Can't beat the simplicity of the 6.2 off-road. Fuel injection type performance when off-camber with hardly any electronics and good low end torque.

I ran for years with 35" radials and 3/4 ton axles, along with the stock 6.2, 700r4, and 4.10 axles. It was a pretty fun ride on the road and moderate trails.
 
#43 ·
my experience with the vaunted 6.2 diesel was with driving an m1026 hmmmv.

biggest piece of shit ever. getting pulled from a stop sign by a vw beetle sucks ass. getting beat to 60 mph by the same beetle really sucks ass. being stuck doing a max of 85 on the audobahn sucked so much ass it is rediculous.

but, thats my opinion. as far as mileage goes, i never really tracked it. it couldnt have been good, because we had to keep them pinned everytime we drove them. cruise? wtf is cruise rpm? it was either on the floor, or parked. if you let off the throttle, you were fucked.

it has always been the epitome and definition of not having enough power to "pull a sick whore off a piss-pot".

of course there are people that love them. People love necrophilia and bestiality. that doesnt make it right. Just look how popular the "Twilight" movies are.
 
#44 ·
my experience with the vaunted 6.2 diesel was with driving an m1026 hmmmv.

biggest piece of shit ever. getting pulled from a stop sign by a vw beetle sucks ass. getting beat to 60 mph by the same beetle really sucks ass. being stuck doing a max of 85 on the audobahn sucked so much ass it is rediculous.
I had plenty of seat time in HMMWV's myself. Had to work on em too :( Anyway, yeah, 148HP (at sea level) in an 8000+lb truck with the aerodynamics of a shithouse doesn't make for a thrilling ride. OTOH, knowing what numnuts the average GIs were that was probably A Good Thing ™. Besides 85MPH in a HMMWV (if it even got there - I never had it happen) has gotta be pretty scary anyway. Now, 165HP in a 5500lb K5 wasn't too horrible. It felt about the same as the TBI 350. Like I said, you weren't going to mistake it for an afterburning J79 strapped to your ass, but it was adequate. Barely.

it has always been the epitome and definition of not having enough power to "pull a sick whore off a piss-pot".
In a HMMWV I would say it didn't have enough power to "pull a greased string out of a cat's ass" :D
 
#46 ·
MAX & GRUMP, you guys hit the nail on the head completely.

getting back to the title of the thread, yes a 6.2 with a turbo is really that bad. the turbo's i have seen on 6.2's are of a terrible design. they were a single turbo adapated onto stock exhaust manifolds, so there was an adapter tube about 4 feet long between the end of the manifold to the inlet of the turbo. this is horrible for a turbo. turbo's don't just need exhaust flow, they need heat from the exhaust to work. the closer you can get the turbo to the exhuast valve, the better they work. this is key to defeating the dreaded 'turbo lag'. i have driven 6.2's equipped with Bank's best attempt at a turbo for them, and the performance was, well, extremely lacking. press the go pedal and 15 seconds later the turbo starts to spool up, then you start to go. really, really pathetic.
if you look at the exhaust design of the new and newer dirtymax's, they have a really short exhaust. the newest design yet is going to place the exaust in the center of the engine valley, making the exhaust path less than 12 inches to the turbo.

now let's not even get into the crappy design of that horrible cylinder head cracking, no power making piece of crap known as a 6.2. even the coveted 'j' series, let's just say they arent worth thier weight in scrap.
 
#50 ·
now let's not even get into the crappy design of that horrible cylinder head cracking, no power making piece of crap known as a 6.2. even the coveted 'j' series, let's just say they arent worth thier weight in scrap.
They ain't that bad. To begin with, although the heads "crack", I have yet to see one where the crack was anything other than a surface crack - they didn't penetrate to the water jacket. I have heard of it, but it seems to be the exception rather than the rule. There's lot sof these things out there that go a shitload of miles with no issues.

The biggest problems with them is that the block can't handle really high levels of power... even IF you can get the pump to deliver enough fuel to make "really high levels of power". AMG's latest version of the 6.5, called the P400, can handle lots of power thanks to a bedplate, forged crank, new design rods and Mahle pistons, piston oilers, and other mods. Still, you have to run a DB-4 pump to get enough fuel to get over 250HP, and the IDI design rejects a lot of heat into the cooling system so it had best be up to the task. Also, running high power means you need to drop the compression to the 18:1 range, which makes cold weather starting a PITA.

If you want to see a "built" 6.2, here's one I did a few years ago. I'm running a Cummins now, so, well, you know :smokin:
 
#48 ·
I still see no problems in just wheeling a stock 6.2? It can still be driven on the street under it's own load plus a couple people relatively easy I'd say. I'm willing to bet it would go down more trails than that Ford. Just wouldn't have the towing capacity.
 
#52 ·
if you wanted to reduce the load or work your engine and that 7.17ratio were a viable gearset to do so then yes you could do that... it is kinda what the oems do, change the mechanical advantage to reduce the energy consumption/force applied to accomplish the same thing... which basically = less fuel for the same work, which is exactly how lower gears with overdrives= better mpgs. is it really that hard to figure out? and 410s arnt that low just kinda low for a 6.2. so really your just exaggerating it to try to make a point that you think you have but you dont.
maby your the one who eats paint.

This is all bullshit. Please try to explain again how deep reduction gearing in the diff helps fuel mileage and at the same time overdriven gearing in the trans also helps. I need another laugh today.
 
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