is 6.2 a good motor?

[akbogger52]

hey everyone, i am looking at getting a 1983 blazer k5. it has a good running 6.2 with 60,000 miles on it. i have been hearing a mixed opinion on these motors from people i have talked to. is this a good, strong, motor. also, how is the gas mileage and power in this diesel??? And last but certainly not least, how much does it weigh, because i dont wanna sink in the mud. thanks everyone!!!

[93M6Formula]

They did have their ups and downs but if you kept up on maintenance and take care of them they will run forever. And with the low miles this K5 you're talking about has, it seems like it's sure to be a good motor. I've owned two 6.2L Diesel trucks and a 6.5 and they have all done the job just fine. My 82 GMC 6.2 that I just sold would average 21-23 MPG all day long and usually 17 or so in town. They weren't the most powerful but that's nothing a turbo can't fix. The K5 diesels usually saw a little better MPG than the trucks but were given the "weany" injector pump and usually are underpowered, but you can turn up the pump a little bit to give it some more get up and go. I'm sort of obsessed with these motors actually and know way too much about them but oh well haha.

[93M6Formula]

Also for the weight, they are roughly 100 or so lbs heavier than the standard gassers but I actually have had good luck getting around with that extra weight in the front, especially in the snow.

[Koots]

I have an 83 K5 as well.

The 6.2L is a good economy motor in stock form, but it's nothing much to get it to 6.5TD power levels and beyond with some money and patience. The issue with the diesels is they don't have a lot of wheel spin so they don't flick mud as well as a gasser, in stock form.

Look around you for a single or dual plane J-code intake manifold from the 3/4 and 1 ton trucks. This, plus turning up the fuel screw on your fuel pump should give you a nice boost in overall power. Even getting rid of the EGR on mine was enough to feel like a 10-15HP difference in my truck

I'm in the process now of fine tuning this new injection pump i have. Its a pump from a 6.5TD military Hummer, so it should throw out tons oof fuel for my N/A truck along with a huge intake manifold from a 6.5TD as well.

[Koots]

I can also attest to the mileage claims 93M6Formula says he got. Back before the lift and 35s i was able to get 17-25MPG city/highway easily.

Now with 35" BFG mud terrains, 4" Tuff Country lift and the stock 3.42 gears, i got 16MPG on a road trip, which was better than my 2500HD ever got

[akbogger52]

sweet everybody, sounds like this truck with minimal rust or 1900 isnt too bad of a deal... thanks everyone!

[Koots]

Don't listen to what most say about these engiines, most think they are just a bigger version of the Olds 5.7L, which is completely untrue on all accounts. They have their limitations, but can be made to make great power and can outpull any smallblock on the market...even some big blocks. A modded turbo 6.2/6.5 can pull just as much as a 454 or more, while returning much better economy.

I'm on the other side of the continent in Labrador, which is probably the same climate for the most part. So i will tell you that these things can be a bitch to start in the winter. A good set of ACDelco 60G glow plugs or Bosch Duratherms and a glow plug override mod will help immensely:



This is what i did and it works awesome and because you are only wiring the switch to complete the ground circuit, you don't have to worry so much about blowing up the switch.

I'd also get 2 brand new batteries with the most amount of CCA's available, plus upgrade your battery positive and ground cables. That and a good pair of block heaters should prepare you for the worst the winter can throw at you. I know here in Labrador we get some crazy weather and this truck was able to make it through. Just as long as you don't leave it unplugged and cold for more than 5 hours straight it should start up anytime.

[Koots]

Don't listen to what most say about these engiines, most think they are just a bigger version of the Olds 5.7L, which is completely untrue on all accounts. They have their limitations, but can be made to make great power and can outpull any smallblock on the market...even some big blocks. A modded turbo 6.2/6.5 can pull just as much as a 454 or more, while returning much better economy.

I'm on the other side of the continent in Labrador, which is probably the same climate for the most part. So i will tell you that these things can be a bitch to start in the winter. A good set of ACDelco 60G glow plugs or Bosch Duratherms and a glow plug override mod will help immensely:



This is what i did and it works awesome and because you are only wiring the switch to complete the ground circuit, you don't have to worry so much about blowing up the switch.

I'd also get 2 brand new batteries with the most amount of CCA's available, plus upgrade your battery positive and ground cables. That and a good pair of block heaters should prepare you for the worst the winter can throw at you. I know here in Labrador we get some crazy weather and this truck was able to make it through. Just as long as you don't leave it unplugged and cold for more than 5 hours straight it should start up anytime.

[akbogger52]

well i live in kenai, alaska... so i think this would be a pretty damn good test!!! haha

[akbogger52]

and i forgot to mention... it has a banks turbo (:

[Koots]

well i live in kenai, alaska... so i think this would be a pretty damn good test!!! haha

That's what i mean by we have nearly the same climate. and are nearly the same latitude. So we experience the same winter temps anyway, you might have it a little colder for longer periods though. We have pretty damn hot and rainy summers now that "global warming" seems to have gotten rid of our nice dry summers.

The Banks turbo setup is a solid system, but there is always room for improvement

[akbogger52]

what are my options for aftermarket exhausts???

[Koots]

Very little exhaust options for these old K5's, the only catback i found was a 3" system from Flowmaster. Which is a good size for most any 6.2L and as much as i hate flowmasters...they sound fvckin awesome on these motors:



Otherwise, your truck should have true 2.25" duals, which is a nice setup anyway. Just throw some mufflers of your choice on and enjoy the sound! These engines may be slow but they sound like a monster while doing it.

[6.0 Bowtie HD]

These engines orginally started life as 350 gas blocks converted to 6.2 diesels. The DB2 injection pump Koots picked up from the hummer can throw quite a bit of fuel and theres an adjustment screw inside the old ones under the govenor housing, but have a tendency to fail after so many cylces. We have so many of these engines in our CUCV trucks that are just destroyed. Too many roll in and out to count the problems. The 6.5 in the Hummers is a more reliable engine but it too is a piece. I personally would not own one but my expierince is limited to beat to hell military equipment older than myself.

[Koots]

These engines orginally started life as 350 gas blocks converted to 6.2 diesels. The DB2 injection pump Koots picked up from the hummer can throw quite a bit of fuel and theres an adjustment screw inside the old ones under the govenor housing, but have a tendency to fail after so many cylces. We have so many of these engines in our CUCV trucks that are just destroyed. Too many roll in and out to count the problems. The 6.5 in the Hummers is a more reliable engine but it too is a piece. I personally would not own one but my expierince is limited to beat to hell military equipment older than myself.

Yeah, leave the info for someone else to spout, because these ARE NOT CONVERTED GAS BLOCKS!!!. These are a Detroit Diesel design meant to be a diesel all along. The thing that confuses people is the fact it was designed to fit SBC mounts and accessories so it can be confusing.

But even the Olds 5.7/4.3 diesels weren't converted gas blocks, they were based on the gas blocks but strengthened to handle diesel compression. These engines share nothing other than injection pumps with the 6.2/6.5.

Also, just because you see heavily abused/terribly maintained engines in vehicles too heavy for a light duty block doesn't mean it's weak. The HMMWV is running an engine originally designed to offer a fuel sipping alternative to gas V8's. So it's no surprise that they fail a lot. People need to learn more about these engines before they dismiss them as trash!

[Koots]

Sorry if i sounded a bit angry, but i just hate seeing sooooooooooo many people posting the wrong information about these engines all over the internet.

So it's easy to get angry when i see it. My apologies if you were offended as that was not my intention

[454cid]

These engines orginally started life as 350 gas blocks converted to 6.2 diesels.

Thats' just plain wrong.

[grayblazer]

These engines orginally started life as 350 gas blocks converted to 6.2 diesels. The DB2 injection pump Koots picked up from the hummer can throw quite a bit of fuel and theres an adjustment screw inside the old ones under the govenor housing, but have a tendency to fail after so many cylces. We have so many of these engines in our CUCV trucks that are just destroyed. Too many roll in and out to count the problems. The 6.5 in the Hummers is a more reliable engine but it too is a piece. I personally would not own one but my expierince is limited to beat to hell military equipment older than myself.

"If I had a dollar for everytime I heard this" was the first thing that came to my mind when reading this, especially considering a few posts up a person specifically stated this was not true. This is one of the biggest myths with the 6.2 engines and part of the reason it always had a bad reputation.

I've owned a 6.2 K5 for 17 years including through my teenage years where I ran the pee out of it, and now it's a dedicated trail truck that gets used hard and put away wet. The deepest I've been into the engine was a new water pump and new glow plugs. Back when it was stock except for 32" mud tires I averaged 18 MPG in mixed driving and running it hard. Definitely not a powerhouse but compared to stock offerings of the same time it was comparable, and fast enough to get a few speeding tickets on the freeway.

With good batteries and working glow plugs I never had trouble starting in the winter while in the midwest (dipping around 0 at times).

[454cid]

"If I had a dollar for everytime I heard this" was the first thing that came to my mind when reading this, especially considering a few posts up a person specifically stated this was not true. This is one of the biggest myths with the 6.2 engines and part of the reason it always had a bad reputation.

I actually had never heard anyone say that about the 6.2L before reading this thread. Usually it's the 350 Olds diesel that gets labeled as a conversion, which isn't true either........ unless you maybe you think of conversion as being at the blueprint level, as GM did design it to use some Olds 350 tooling, and be installed in the same places, but the important parts were different.

I've heard the 6.2 and/or 6.5 were based on the 454, also not true.

[Koots]

I think the actual size of the block makes it look like a big block, it's a helluva big motor compared to the SBC's i'm used too. While i was wrenching on my truck the other day, this guy next door came up and mentioned that his friend was building up a K5 and the 305 he has in it is much smaller than the 6.2 and that was with the intake manifold and IP off