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GM Diesels Suck



  • stanfordstanford Posts: 606
    Of course, navistar produces several 7.3l "powerstroke" type engines with higher outputs, just as cummins does. Although I will admit that they don't scale as far (top of the line Cummins runs around 2,000 lb feet). It's all in the transmissions.
  • hcombs0hcombs0 Posts: 22
    Does anyone have any prediction as to where this power war will all end? Is it possible that we'll all be driving 600ft-lb diesels in 2002 or beyond?

    Also, why aren't diesel engine prices coming down? It seems to me that diesel engines are becoming more popular, and this should mean that manufacturers can spread-out costs more effectively, reducing unit price. However, the opposite is happening. Any ideas?
  • richflynnrichflynn Posts: 147
    The '99 PS 7.3L in my F-250 accelerates like a smaller gasoline (non V-10) engine would. Very impressive but not of much use at the stop light drag races.

    In comparison:
    The '99 PS 7.3L is rather quick and snappy;
    The '92 7.3L (non turbo) was acceptable;
    The '86 6.9L couldn't get out of it's own way;
    all three had a 3.73 rear end. Only the '86 was non LS.

    The '86 went through the Eisenhower tunnel on I70 at about 48-50 MPH while flat towing a Datsun 310 and carrying three adults with luggage. (For those of you who aren't aware, that's about 11,000 feet above sea level. A good example of torque too.) I was driving by the color of the exhaust. Clear, more throttle; black, less throttle.

    In all three trucks, I've never been happer with the drivability (Is there such a word?) of the diesel engines.
  • cdeancdean Posts: 1,110
    as power goes up on a diesel, so does the price. It is very expensive to get that kinda power into that displacement. those pre powerstroke 7.3's damn sure didn't cost $4500. innercoolers, turbos, hightech injectors, cost lots of money, lots! then, once you give yourself the ability to make all that power, you have to beef up the pistons, block, crank, rods, and cooling system, all so you can handle the power and dissipate the heat. diesel engine prices won't go anywhere but up. unless the engines get simpler. right now, diesel motors are the most complicated motors in trucks.
  • hcombs0hcombs0 Posts: 22
    That's sort of ironic, isn't it? A diesel being more complicated than its gas counterpart?
  • cdeancdean Posts: 1,110
    thats not ironic at all. i've worked on diesels since i was a kid. the simplest diesel is more complicated than the most complicated gas motor. Any average mechanic can go through an entire gas motor by himself. there are no complicated parts, nothing really special about them. newer motors with computers require you to have a code reader or some sort of software downloader. and thats it. the rest is like building a model airplane.

    There is no way an average mechanic can go through a diesel engine all by himself, even older ones, like 80's model engines. fuel pumps on diesels must be sent to specialty shops that have special tools and test equipment built specifically for diesels. those pumps have incredibly tight tolerances, small gaps, special screens (interior filters that are so fine, water cannot pass thru), and other intricacies. your cheapest rebuild of a simple fuel pump in the late 80's early 90's was in the $300 range.

    then there are injectors on diesels. there are only a few places in the country that actually work on injectors, and those are usually the producers. most of the time, you don't work on an injector; you buy a rebuilt set, and give yours to the dealer, and he sends them back to the factory in Timbuktu.

    turbos are extremely expensive, and are only worked on, built, or fixed in specialty shops. turbos spin at such incredibly high rpms, they have very specific bearing tolerances, and lubrication requirements, as well as high tech metals used for material, so they can withstand the heat.

    now, within the last 5 years, the diesels have become computerized. take all the crap i mentioned above, and throw in complicated fuel injection software that only a handful of engineers in the country actually understand. they only tell the servicemen how to fix it or reprogram it.

    if you thought buying a diesel is expensive, you better sit down when it comes time to fix it. everyone says diesels last longer than gas engines, but truth is, over a period of 200,000 miles, the only thing that you really have to replace (given good maintenance) is distributor, plugs, wires---ignition stuff. fuel pumps on these new computerized diesels today rarely make over 120k-150k at the most. that eats up about $1000. then you have injectors to go wrong, head gaskets more prone to blow. i can buy a lot of caps and rotors for that money.
  • hcombs0hcombs0 Posts: 22
    I hear you, especially about the fuel pumps. One of the reasons people hate the GM 6.5L is the problem GM had with electronic fuel pumps in 1994-1996.

    I was just saying how ironic it is that diesels these days are so complicated, since when they are conceptually simpler (no ignition system). I'm sorry if I touched a nerve.

    I know I'm asking lots of questions here, but diesels interest me a lot, not just practically (towing power) but conceptually (efficiency, special concerns). This conference has been a great help to me.
  • cdeancdean Posts: 1,110
    no prob, you didn't touch a nerve, i just didn't want anyone to think diesels were simple, because i mechanic-ed them for a long time, and know there is a lot to go wrong. you are right about the chevy '94-96 fuel pumps. they had probs with fuel pumps themselves and/or software. the trucks don't even have throttle cables, just a wire running from you foot pedal to the pump. technology is tops, but if it doesn't put out, then who cares. the chevy diesel has been maxed out as far as how much they get out of the current design, and it is about time they go somewhere to get a better one. they were competitve in the pre powerstroke era. engine power same as ford, just under dodge, and engines lasted. in '94, they got left behind.
  • glenn2glenn2 Posts: 39
    I guess the title says it all.....
  • I think that all of ya"ll are makeink a big deal out of nothing be cause i drive one with deseal in it and it does every thing i need it to.
  • The reason the chevy diesels are so disliked is that they really are an optional engine for the 350 not the 454. I can see why consumers would be pissed as spending a lot more money for an engine that does not provide as much or more hp and torque as the 454. I personally like the idea of a mid sized diesel engine (as long as its inexpensive). But the guys who need the power of a big block and want a diesel will be spending their money at the local dodge or ford dealer. Come on Chevy, get with it!
  • KCRamKCRam Mt. Arlington NJPosts: 3,516
    The GM/Isuzu diesel was announced today:

    6.6L V8 direct-injection turbo

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