Why do people bash the CUCV?

[jdemaris]

i have a m1008 with blazer axles with 3.08 gears and a sm 465 tranny and every thing else is completely stock and i get 27-30 mpg at 60-65 mph

27-30 MPGs defies reason and physics. No offense, but I don't believe you. Maybe you actually believe those figures - and if so, I have no idea why.

I've met with a few people that made such claims and every one I had a chance to check, got nowhere near those figures. If you DO actually have one, it must truly be magical.

I've got over 20 6.2 diesel rigs. Also have been repairing and modifiying them since they came out. I've checked mileage on all in varioius conditions, drive train options, engine options, includimg long trips down south on flat roads.

A few years ago, there was a 6.2 diesel fuel-mileage contest. Held in the southwest at low altitude, with warm weather and flat highways. A modifed 1/2 ton 2WD short-box pickup with 2.73 axle gears. overdrive manual trans, and small chamber heads won the contest with 23.5 MPG. Seems you should of entered?

I can verify that my little mini Isuzu PUP 4WD diesel pickup with a 2.2 diesel does indeed get 31 MPG on highway trips.

So why do you suppose a new, factory fresh diesel Blazer with 3.08 axles and .7 of overdrive only got 21 MPG, yet your's does SO much better?

By the way, I have a factory stock 1982 1/2 ton pickup with C-code 6.2 diesel (more efficient then a J-code). Has 3.08 axles and a New Process NP833 four-speed manual trans with overdrive. It was tested for a year in Long Island at sea level, in warm weather highway driving. 22 MPG was the highest ever recorded . Overall average of 16.5 MPG.

 

[aph1979]

My favorite story about my M1009 was from an average trip to ACE Hardware. A truck pulled in behind me with a dad and his two kids, 5-7 years old. I caught him eyeing Sgt. Rumble and as we walked into the story he told me he thought it was a great truck. His youngest kid turned and said, "No daddy, you said it was ugly garbage". The look on his face was priceless.

 

[linx310]

What do you think the mileage is if you stick around 55-60 mph on the highway?

That mileage contest gives me an idea...we should truly see what people get. Perhaps people could take a pic of there odometer and scan in fuel logs. Would really be interesting to see what the true numbers are?

 

[Novice1]

I had always heard that the 6.2L block was based on the the old 348/409 truck block. This block was a good foundation base (not in hind sight) for the new diesel and GM still owned all of the tooling for the block (this was the real reason) so they handed off the original blue prints to Detroit Diesel and said here make a Diesel out of this.
I've not been involved with this engine but I do live in Indy where there has been, until recently, a large Detroit Diesel install base. I grew up here and over the years I have met a lot of people who have worked for DD and this is the rumor I've always heard.

 

[Novice1]

I had always heard that the 6.2L block was based on the the old 348/409 truck block. This block was a good foundation base (not in hind sight) for the new diesel and GM still owned all of the tooling for the block (this was the real reason) so they handed off the original blue prints to Detroit Diesel and said here make a Diesel out of this.
I've not been involved with this engine but I do live in Indy where there has been, until recently, a large Detroit Diesel install base. I grew up here and over the years I have met a lot of people who have worked for DD and this is the rumor I've always heard.

 

[Cucvnut]

The 348 block went out of production in like 60's

 

[Barrman]

It seems that if a person were to drive from point A to point B, figure out how many miles the distance seperating the two points are and then divides that by the number of gallons used. They would be able to figure out the miles per gallon. It doesn't take 20 years of ownership to do that simple math formula.

My worse tank was 15.6mpg and my best has been 24.6mpg. The fact that "topping off" the tank can vary how many gallons go in by as much as 2 or 3 or more on a M1009. (I have never been able to stop pumping and still have the fuel in the filler neck 2 minutes later with the engine off. No matter how long I stand there putting fuel in at a dribble. I normally get tired of playing that game and move on down the road.) Means that tank to tank mileage really isn't as accurate as we would like to think. Averaging a dozen or so fill ups is a better representation of actual fuel use. Before we got below freezing out, my 6 month fuel average was 20.8 mpg. City, highway, hauling Boy Scouts, going through drive thru's and such. Straight highway runs with GPS speed and distance numbers always get me over 22mpg. I don't run over 65 and normally try to stay around 60-62 with 33x12.50 tires. Call it impossible all you want, tell me I am an idiot or liar, I don't care.

Now, to the thread topic. I was a CUCV basher until I started looking at the numbers. Then I wanted one. Now that I have one, I want more. The M715 sits a lot. The M35 Whistler sits more. The M35 Gasser gets started and moved a few feet every other week. My wife actually drives the M1009 on the weekends, and likes it! No other vehicle besides our family Suburban is accepted by her which means my entire herd is looked on better because of that one truck.

 

[Myopic]

Because it's a chevy, built in the mid 80's with a low power engine and full time 4wd.

Those who can't see the value of AWD have simply never owned one.

If the military had spec'd a 350 and a manual transmission in them,umm...
this thread would not exist...

M1009/8/28 have Part-time 4WD. Full-time 4WD is typically referred to as AWD. And isn't AWD a marketing term for Traction Control?

dunno why I thougt they were full time, maybe the auto-locking hubs looks like drive flanges?

I have known for ages that gm switched to part time in 1978/9. Just thought that cucv's kept it for better traction and handling.

 

[Wmwaller]

Since I am new to the world of MVs, what should I look for when checking out the M1009 this weekend?

 

[dstang97]

Because the 6.2 is just a Gas 350 converted to diesel. LOL

Most people bash Cucv's because they do not know how to work on them because they are not smart enough to use the search function or take the time to fully understand the manuals.

 

[dstang97]

"Because the 6.2 is just a Gas 350 converted to diesel." LOL

Most people bash Cucv's because they do not know how to work on them because they are not smart enough to use the search function or take the time to fully understand the manuals.

 

[bubba_got_you]

CAUSE ITS A CHEVY! lol this coming from a guy with a 66 gmc with a 6.2 in it

 

[jdemaris]

It seems that if a person were to drive from point A to point B, figure out how many miles the distance seperating the two points are and then divides that by the number of gallons used. They would be able to figure out the miles per gallon. It doesn't take 20 years of ownership to do that simple math formula.

Yes, but you certainly need more then a few tank-fulls to get an accurate reading. At many pumps, it''s impossible to truly fill a diesel tank in a Blazer or pickup. The factory filller neck is too small. They pump diesel too fast an load it with air, causing it to foam. All depends on the pump. If you find a place that actually has a smaller pickup-truck rated low-flow pump, a fill is much easier. Most I go to for fuel only have the big-rig, big-nozzle pumps that put a lot of air and foam in the tank.

Last long trip I took with a diesel was 4000 miles. I logged every "fill" and every drop of fuel. I had a few tank "fulls" that calcuated at 28 MPG. That because the tank was loaded with air. Of course, often the next "fill" would calculate at 13 MPG. So, yeah, I could brag about getting 28 MPG at "best", but it''s BS. On that last 4000 mile trip, I got 18.5 MPG. Not bad considering I was driving near 80 MPH at times.

The longer you keep track and calculate a long-term average, the more accurate the figure will be.

Ive got over 20 years of averages for many GM 6.2 diesels. Also for my two Ford-IH diesels, Isuzu diesel pickup, and my 92 Dodge-Cummins.

All my Blazer 6.2s with 3.08s and no overdrive get 16 MPG all-around and 20 MPG best. Years 1983 to 1986.

All my Blazer 6.2s with 3.08s and overdrive 700R4 plus lockup converter get 16 MPG all -around and 22 MPG best. Years 1983, 1986, and 1989.

My 3/4 ton 4WD diesel Suburbans with T400 trans (no OD) and 3.73 axles get 13 MPG all-around and 18 MPG best. 1987 and 1989.

My 1/2 ton 4WD diseel Suburgan with 4L60 trans and 3.42 axles gets 14 MPG all-around and 20 MPG best. 1991

My 1/2 ton 4WD diesel pickup with 3.08 axles and and four-speed manual overdrive gets 17 MPG all-around and 23.5 MPG best. 1982 with rare NP833 manual OD full syncro trans.

My Blazer with built-on mini-motorhome body and a 700R4 trans and 3.08 axles and Banks turbo gets 16.5 MPG best. Has a pop-up roof and weighs 7000 lbs. 1986, with 1991 V20 running gear.

1992 Dodge-Cummins 5.9 intercooled-turbo, 4WD, extended cab, 5 peed manual Getrag with OD and 3.50 axles gets 20.5 best highway mileage. 17 MPG with a slide-on camper and driving 75 MPH.

1994 Ford F250 with turbo 7.3 IDI diesel, 4WD, extended cab, E40D overdrive auto and 4.10 axles gets a best of 17.5 MPG highway and 14 MPG with a slide-on camper.

 

[jdemaris]

Back early 80s, I saw many 6.2s get removed and condemned for what were really simple problems. That because of the Oldsj-350 fear. Like I said, I'm glad. I saw a few 6.2s with only 30K miles get pulled and trashed when all that was wrong was the glow plugs - or failed plastic ring inside the injection pump.

Rember that for the first five years of 6.2s, ther glow plugs failed constantly. The injection pumps failed often. The head gaskets leaked in 1982 and 1983s. Direct-drive starters has short lifes. And the 700R4 transmission were so awful - many transmission shops refused to work on them if a warranty was required. By 1986 most engine problems were ironed out, and by 1988 most auto-trans problems were finally fixed. Also in 1988 the gear-reduction starter became standard.

Then, in 1994, the problems started all over again with civilian 6.5 diesels and electric-controlled injection pumps. They failed all over the place. Neither GM or Stanadyne had a good fix and GM got sued. But by 1997-1998, all was figured out - again.

 

[McCluskey]

Yes . . . I've heard many BS stories and "pipe dreams" about diesel fuel mileage for 50 years.

There is not a K5 Blazer with a 6.2 on the planet that gets 26 MPG. Best case is a C-code Blazer with stock 15" tires, overdrive trans and no torque converter slippage, 3.08 axle ratios and driven at sea level with high-sulfur fuel. That can get 21 MPG at 65 MPH on a flat highway.

A military type Blazer with 3.08 axles, fat tires, and a T400 trans will get around 16 MPG average all-around mileage and 18-20 MPH on a flat highway run.

I do know of a Blazer with a 3.9 liter turbo Cummins that can get up to 25 MPG.

27-30 MPGs defies reason and physics. No offense, but I don't believe you. Maybe you actually believe those figures - and if so, I have no idea why.

I've met with a few people that made such claims and every one I had a chance to check, got nowhere near those figures. If you DO actually have one, it must truly be magical.

I've got over 20 6.2 diesel rigs. Also have been repairing and modifiying them since they came out. I've checked mileage on all in varioius conditions, drive train options, engine options, includimg long trips down south on flat roads.

A few years ago, there was a 6.2 diesel fuel-mileage contest. Held in the southwest at low altitude, with warm weather and flat highways. A modifed 1/2 ton 2WD short-box pickup with 2.73 axle gears. overdrive manual trans, and small chamber heads won the contest with 23.5 MPG. Seems you should of entered?

I can verify that my little mini Isuzu PUP 4WD diesel pickup with a 2.2 diesel does indeed get 31 MPG on highway trips.

So why do you suppose a new, factory fresh diesel Blazer with 3.08 axles and .7 of overdrive only got 21 MPG, yet your's does SO much better?

Driving my M1009 home from Denver to Los Angeles, I averaged 24.6 MPG over the 1100 miles. Best stretch I got 27.1 MPG. And is is coming from 11,134 feet all the way down to 400 feet through snow, ice, wind, etc then mellowing out by the time I got into Utah. It was just the empty truck with my 285lb ass and 2 3-day packs in the truck. So basically empty. We cruised a consistent 65MPH most of the way home. And were doing good miles. Winter fuel Diesel gives you better MPG maybe? Combined with fuel treatment was giving me good MPG? I have no idea, I just worked the mileage off my Speedo and GPS and measuring the needle while in motion off the fuel gauge. I was very consistant in how I drove, fueled, and measured and I calculated those numbers.

 

[kaveman31]

just took a 230 mile trip with my 86 m1009 got about 17.6 mpg. high for the day was about -2. i also run power service.

 

[mr.travo]

I don't give a **** what anyone says, I love my CUCV's! They are fun and tough. I also have a nice '07 Dodge Ram 3500 5.9L Cummins. It's really nice and gets great fuel mileage, but I love driving the CUCV's. I loved reading a lot of the "bashers" reasons why CUCV's suck. I just laugh. If you don't like them, quit trying to convince other people to join you. We are fine in our M/V and CUCV world.

Just my 2 cents......

 

[jdemaris]

. I loved reading a lot of the "bashers" reasons why CUCV's suck. I just laugh. If you don't like them, quit trying to convince other people to join you. We are fine in our M/V and CUCV world.

Just my 2 cents......

I'm not sure what you are calling "bashing." There is plenty of incorrect info floating around, but reporting known problems is not what I'd call "bashing."

I give the original GM (not Obama's) credit for being the the only USA automaker to build their own diesel for use in 1/2 ton trucks. Nobody else, up to now, has tried it. Jeep did offer a Perkins in the 60s, IH offered a Nissan in Scouts, and Dodge offered a Mitsubishi for one year in 1978.

From what I've seen over the years, the #1 problem with diesels in the USA is diesel-ignorance. Most US consumers knew nothing about diesels when they first became available in small vehicles. To make things worse, most auto repair shops also know nothing, but try to fix anyway.

Note that saying a diesel was made from a gas engine need not be a bad thing. It is not true with the 6.2, but IS true with many others. The Ford-IH 6.9 and 7.3 was made from an IH truck gas engine. So was the GMC Too. So were 1.8 and 2.2 Isuzu diesels used in Chevettes, LUVs, S10 trucks, PUPs, Imarks, etc. So were most Volkswagen diesels.

The biggest problem I've seen with USA diesel ignorance - is the myth that all diesels are high torque and powerful. The truth is, all diesels have less power then gas engines- if they have the same bore and stroke and no turbo. Same goes for torque. It's a long stroke that makes torque, in a gas or diesel engine. When the 6.2 came out, many 5.7 liter gas engine owner's thought the 6.2 would at least have equal power to the 350 (5.7). It does not. The 378 c.i. "6.2" was made to have equal power to the 305 gasser (5 litre).

 

[mckeeranger]

Since I am new to the world of MVs, what should I look for when checking out the M1009 this weekend?

Pretty much the same things you would look for on any truck or Blazer.

Look for major leaks around the engine, transmission, differentials, and brake components.

It should track strait when driving and braking. Look for uneven wear on tires, and check for tight steering. Make sure the brakes have plenty of pedal and plenty of braking power.

These trucks don't have the insulation of a civy truck, so be ready for more road noise and mechanical noise. I don't know how much mechanical experience you have, so please don't be offended when I say if you can't tell the difference between road noise and a bad bearing, take someone along that can.

The engine should start fairly easy and run smooth. They are noisy, but should not shake when warmed up. the transmission should shift smooth and solid.

If it is still the original 24 volt system, it will have 2 batteries and 2 alternators. If it only has one of each, it has been converted to 12 volt. GM trucks sometimes catch a lot of flack for having poor electrical systems, but in my experience the biggest problem is people hacking into the harness to "fix" something. A chopped up harness makes it nearly impossible to track down electrical gremlins.

Good luck on your search for a good CUCV. I would love to own one, but I'm concentrating my funds on my 53 F100 build. Maybe later.

 

[jdemaris]

It should track strait when driving and braking.

The engine should start fairly easy and run smooth.

If it is still the original 24 volt system, it will have 2 batteries and 2 alternators.
If it only has one of each, it has been converted to 12 volt.

A few addded comments.

Even K5 Blazers with perfect suspensions won't alway track perfectly straight, especially with oversize tires on bumpy roads. That's due to the short wheelbase.

A perfect engine might run kind of lousy when first started if it's cold. Not all good engines were created equally. When built at the factory, there are many plus-minus tolerances allowed. So, even when in perfect condition, not all 6.2s behave the same when cold.

In regard to batteries, Civilian rigs with 6.2 diesels and 12 volt system also need two batteries unless you only start the engine at temps over 70 F.
Two batteries in series to run a 24 volt starter make the same power as two batteries hooked in parallel to run a 12 volt starter.