ArmyofOne

I have to say I disagree with you. Maybe at the time they were unreliable...maybe. but GM still produces these motors for the US Army today. We use them in the Humvee. (soft version). The Armored ones receive a 6.5L Turbo diesel. Still the same engine, just different external components.

Now, that said, we replace engines all the time. But look what we put them through. I would call the smal block chevy diesel ANYTHING but unreliable.

And it came with 2 batteries because it required a 24v electrical system...mostly for the starter. 20:1 is a HUGE compression ratio.
Again I disagree. My folks had a 1986 Chevy Astro minivan growing up with the 4.3L. And while it was painfully slow, it was stone solid reliable for 286,000 miles.

I will be thinking about my addition to this today and report back...but for now, I am going to go with any late 80's/early 90's renault engine.

geko29

Sorry, the Humvee does NOT have a GM 2300 4-cylinder engine in it. That motor was discontinued in 1977 due to the issues mmarshall pointed out, and wouldn't have been powerful enough to roll a Humvee down a hill. Perhaps you meant to quote the bit about the gas smallblocks converted to diesel service? But even that would be incorrect.

The engines he was talking about here were ended in 1985 (again due to the problems he outlined). The V8 version was the Oldsmobile LF9, and was 350 cubic inches (5.7L). It was based off the Olds 350 V8. The 6.2L (379 cubic inches) Diesel in the Humvee is a Detroit Diesel LL4 that was introduced in 1982. COMPLETELY different design. This was replaced in 1993 by the 6.5L (395 cubic inches) L57 (just an evolution, not a whole new engine), which is still produced by AM General today under the 6500 Optimizer name.

There's absolutely NOTHING comparable about the abysmal GM gas/diesel converted engines of the 70s/80s and the designed-from-the-ground-up diesels sold under the Detroit brand that are used in the Hummers. Different displacement, design, casting, everything.

FrankReynoldsCPA

I think part of the reason that the current 6500 Optimizer is so reliable is that the block is now cast by Navistar(aka, International) and NOT GM.

I have to disagree with the GM 2.8 on this list. I piled on a lot of abuse on my 1989 Firebird 2.8. Now, that engine isn't going to be winning a lot of races, but it definitely moved that car around just fine and was a joy to drive. Fairly reliable. I bought it at 170,000 and drove it until 200,000. The parts I replaced were mainly the starter(multiple times), water pump, and clutch.

Aron9000

That being the case, my cousin owned a 1995ish Chevy 2500 with the 6.5 turbodiesel/5speed manual. That truck was nothing but a mess of trouble for him. He had to replace all the glow plugs, the injection pump, and a bunch of other junk on that motor. He ended up spending $2000 on a truck he bought for $2000 and sold later at a loss for about $3000.

mmarshall

Did you post the wrong quote, Josh? I think you meant to say you disagreed with my view of the GM 350 diesel V8, not the Vega's aluminum four-cylinder.

Anyhow, having said that, Humvee-ready or not today, it's still a case of apples and oranges. GM, as you note, may have produced more-reliable versions later on for military use, but the original 350 diesels were so bad that they ended up as class-action suits. GM, in those days, produced a lot of sub-standard-quality stuff...it was not limited to this engine by any means. The X-Body Citation/Phoenix/Skylark/Omega was another classic example, but they were more entire-car problems rather than specific engine defects, which is why I did not include them in my initial response.

Fizzboy7

Looking back at old Consumer Reports books, the two GM engines I mentioned got black dots in most catagories. I mentioned the stalling issue in my 4.3 Jimmy. The 2.8 also hesitated severely from a stop. That was the first car I had and I remember having to plan out my lefthand turns, knowing when I hit the gas nothing was going to happen for two seconds. I guess others were more fortunate with these engines, which is good.

ArmyofOne

I quoted the wrong section of MMarshalls post. But I would like to know where you get your info though, because every Humvee Diesel I have EVER swapped has GM and AM General stamped all over it. And its been literally hundreds. Not calling you a liar, but would like to see a source for the info, for my own knowledge. These engines even have GM part numbers. They may be SOURCED from Detroit Diesel. Its very possible I am wrong, but I was under the impression these were the same engines used in the old Chevy pickups from 1976+. Basically a 350 block with diesel heads, glow plugs, and an injection pump and a higher compression ratio.

The engines we order come from a GM plant, with an AM General Sticker and a GM part #. It says Detroit nowhere on it, nor do any of the part numbers. When we order internal engine components, they come from GM as well. You say the engine in question was discontinued in 1985, but the Humvee made its debut in 1982.

I did, Wasn't referring to the 4 cylinder vega. My uncle had one but it exploded on the side of a freeway in a ball of fire in houston.

geko29

Detroit Diesel was a GM brand, just like the current Duramax brand. They were originally GM Diesel until being rebranded Detroit Diesel in 1965. The engines they produced for that application would have been GM-labeled and with GM part numbers, as they were offered exclusively in GM vehicles. You can see the application list here:

http://en.wikipedia.org/wiki/Detroit_Diesel_V8_engine

Regardless of your thoughts on the veracity of wikipedia, just look at it logically. The crappy 1977-1985 Oldsmobile diesel was a 350ci (5.7L) motor, while the modern ones are 379 (6.2L) and 397 (6.5L) cubic inches. How would one go about taking a block that is far too weak to handle compression ignition (most of the failures of the Olsmobile engines were due to cracked heads or blocks), bore and/or stroke it for nearly an extra liter of displacement, and add a turbocharger or supercharger to it? There's just no way such a thing could be done--the engine would explode into a million pieces the first time you fired it.

After GM/Detroit ended the run of the 6.2L, production moved to AM General, and is now done in their General Engines division:

http://www.amgeneral.com/vehicles/gep/products.php

This is why all the blocks would be stamped GM or AM General. Detroit Diesel was eventually spun off to Daimler Chrysler in 2000, but AM General retained rights to the L57 and maintained production.

You can find some more info here:

http://www.dieselpowernetwork.net/idi/62L-gm.html (6.2L/379ci)
http://allenginelist.com/cars/6-2l-v...-engine-specs/ (6.2L/379ci)
http://www.dieselpowernetwork.net/idi/65L-gm.html (6.5L/397ci)
http://allenginelist.com/cars/6-5l-v...-engine-specs/ (6.5L/397ci)
http://www.dieselpowernetwork.net/idi/olds-diesel.html (crappy 5.7L/350ci Olds)

The full timeline of GM diesel V8s is here (bottom of the page):

http://www.dieselpowernetwork.net/id...i-diesels.html

ArmyofOne

Excellent geko, thanks for that. In my job (as with any) knowledge is power. I had no idea about all of that.

Be that as it may, I am sticking to my guns. Renault engines Circa 1989

FrankReynoldsCPA

Yeah, the 6.2/6.5 that are used in the Hummer were produced by GM's Detroit Diesel branch before being sold to AM General. AM however outsources the casting of the block to Navistar. I believe it's a much more stout block than what was put into the GM trucks from 82-00.

toy4two

Turbo Rotaries... 13B-REW, should always have a spare 1.3 litre sitting on the shelf in the garage if you own one. Its just a matter of time. Remember in 1996 walking by the massive service bays at the Escondido Mazda dealership having the Supercharged Millenia serviced, of the 12 lifts, half had RX7's on them, the Mazda mechanic said to never buy one!

Lil4X

My candidate is probably a bit older, but it was stupefyingly bad. The 1949-1952 Crosley Hotshot sported an engine that was the direct descendant of a much-honored powerplant developed for air-drop to troops in WWII. The 4 cyl "CoBra" air-cooled engine block was welded up from "layers" of steel, with stamped rods, overhead valves, and a single carburetor. The Navy specs on the engine required it weigh under 100 lbs, and be able to run at 5000 RPM for 50 hours without service. The Crosley engine accomplished all that with ease, but it had one drawback: at about 60 hours it transformed itself into junk. It was used in dozens of applications, running pumps, generators, refrigeration units, and even the "Mooney Mite" airplane. It's failure was its failure mode. It was never intended to last long, being the mechanical equivalent of a Dixie Cup. It was dirt cheap, simple, and when you used it up, you threw it away. It was never designed to be serviced. Run it 'til it quits, then kick it to the curb - it was not repairable.



By the time the engine was used in the Hotshot in 1949, and later the Super Sport, it had developed water cooling, and produced about 26 hp out of a powerplant weighing in at about 126 lbs. Bolted up to a 85" WB chassis with leaf springs at both ends and sporting a body that would have looked good on a kiddie car, it found a market among GIs returning from the war and looking for a European-like car. Many were familiar with that engine, and although it didn't have the amenities of a "real" car, quite a few were sold. OK, 12" wheels and early disc brakes that tended to seize up at the worst possible moment, aside, the Crosley soon developed a racing heritage. Even if it looked like a pedal car . . . .



Amazingly a Hotshot went to Sebring and LeMans, winning the Sebring Index of Performance in 1951, and leading LeMans for the same trophy when the voltage regulator bailed out late in the race. As it was, Crosley did a lot for sports car racing in the US. It was competitive with the MG of the era, about as sophisticated, and half the price. Plus, that engine, now evolving beyond the old welded block, responded well to basic shade-tree hotrodding, dual carbs, intake and exhaust manifolds, higher compression, and high-octane AVGAS fuel had some examples producing over 100 horsepower.



But not for long.

The old "Dixie Cup" design became painfully apparent, especially in mid-race when the engine would suddenly decide it had had enough, and upchuck its internals on the track. But they had made their mark. Years later, SCCA super modified chassis like the Merlin and the Genie grew out of that lightweight chassis/small engine concept that allowed ordinary people to experience the thrill of real racing on a beer budget. Powered by now by the ubiquitous English Ford 105 engine, these cars were still tiny at around 850 lbs., but regularly took the measure of B and C Production Class Corvettes and 289 Cobras at state and local races. Within a few years, the big teams were stuffing larger versions of these sophisticated chassis with small block V8s and the CanAm series was born. Mighty oaks from tiny acorns grow.

Aron9000

Funny that there are several companies out there now that make every part needed to convert your Rx-7 to a v8. They make parts for 1st, 2nd, and 3rd gen RX-7's. You can have your choice of small block Ford, small block Chevy, or newer all alumium GM LS series V8 motors(really the only way to do it if you aren't on a shoestring budget), these companies sell all the parts you need for those engine conversions.

Although I will say that twin turbo rotary mill in the FD RX-7 responds incredibly well to mods. Its a thrilling powerplant and a real screamer when it is running right. But you are right, they are incredibly finicky and are not durable.

jamieZ

5.3 GM VORTEX 2003 - NOW. Mopped fuel like there was no tomorrow. When you weren't thinking about the 13 MPG, you could worry about cracked heads ( rad fulid smell / fulid in oil)) and manifold studs breaking off. GM sure knows how to build a dog...

Hoovey689

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