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  #16  
Old 09-26-2003, 11:17 AM
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I am a Duramax owner myself, but I have to admit the new Fords and HO Cummins have a slightly higher torque and hp rating. I am not sure about actual "real-world" difference, though. Although with all the Ford injector problems, I will accept a little less overall power. Next year's Dmax is supposed to once again take over the lead. Although it will have an EGR on Federal models (which didn't sound like it would be so bad until I pulled the intake on my 87 Merc. ).

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  #17  
Old 09-27-2003, 11:00 PM
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I can vouch for the injector pump and transmission failing. Both had to be rebuilt on my 84 Chevy K 20 4WD at about 40,000 miles.

In my opinion anything GM builds is crap. They had to ask Isuzu engineers to design their latest truck Diesel engine for them. Probably the Isuzu Diesel will be the best one GM has ever sold.

I wish MB built a Diesel PU truck. Maybe the Sprinter with a PU box and 4WD.

P E H

Last edited by P.E.Haiges; 09-27-2003 at 11:17 PM.
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  #18  
Old 09-28-2003, 09:40 PM
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I had an '82 K5 Blazer with the 6.2, 700R4,and 3.08 gears. it was my main tow beast for several years. Had way over 100k on the clock. Eventually it did need the pump rebuilt and I had the injectors done at the same time. Don't recall changing the pump being a big deal. Looked intimidating, but was really no problem. Biggest problem I had with engine was my own fault. Seemed to eat glow plugs, then I finally wised up and replaced the bad glow plug controller. No more problems after that. Got good fuel mileage. Worst ever was towing camper up and down mountains of KY with air on: 11mpg. Wish my 454 Sub. could do that.
I will agree that the 700R4 was junk. That engine put out WAY too much low end torque for that transmission. That was the reason I finally sold the truck. Transmission went out one time too many.
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  #19  
Old 09-29-2003, 05:19 AM
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Location: Pacifica (SF Bay Area), CA
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I'm going to regret taking this bait...

Quote:
Originally posted by rwthomas1
Ford does indeed have problems with cavitation on the Powerstrokes. They install the additive at the factory. The whole problem started when there was a disconnect with Navistar, the engine builder, and for many years the 7.3's never had any installed from new. Ford does a much better job taking care of their customers with issues like this than GM does. Cavitation is a phenomenon in heavy duty diesels. Well known about and documented, Ford dropped the ball.
I'm sorry; I misspoke. I meant to say that the 7.3l IDI is more prone to cavitation-related failures than either the 6.9l or the Powerstroke, but accidentally said that the 6.9l and the PSD never have the problem. The problem exists on all the Navistar engines (BTW, you mentioned that it's a phenomenon on all HD diesels; if this is the case, how did GM/Detriot/Isuzu and Cummins handle it?), but is much more prolific on the 7.3l IDI. This is because the 6.9l has cylinder walls that are thick enough that other serious problems typically would have arose and pushed a block rebuild before the cavitation would have a chance to get all the way in, for the most part, although it has happened to some people. I'm still talking in the 300K to 400K area; I've only heard of a few cavitation failures on 6.9l's, while they're almost common on the 7.3l IDI's that weren't cared for (and the occasional PSD where the owner didn't maintain the proper amount of additive).

Quote:
The 700r4 (later 4l60e) tranny should never have been used behind a v8 nevermind a diesel. The aftermarket offers many upgrade parts to make a rebuilt unit very tough but stock they are crap. TH400s are just as stout as the 727 Chryslers or the C6. If someone is killing them they have another problem or whoever rebuilt it is an idiot. That said, the GM 4l80e is nothing but a TH400 with overdrive. Offered in 3/4ton chassis since 88? It is also much stronger and better than the Ford or Dodge offerings to date. This is not opinion, just look up the facts.
I won't argue either way on the newer automatics; the Ford E4OD is a complete scrap heap and an embarassing failure on Ford's part, and Dodge's is little better. I was under the impression that the GM overdrive automatic was about on par with Dodge's; where are your facts saying that the GM"s auto is superior? (I'm referring to the 4 speed, not the Allison) That is, however, a moot point for me as I prefer manual transmissions whenever possible (I'm sticking with an auto in the 300D primarily due to the fact that I have a bad back and the car's my daily driver). I wouldn't purposefully buy any American-built diesel pickup with a 4 speed auto; I'd rather go with a gearbox, but if the back gets too bad, I'd rather settle for an old 3 speed, with an aftermarket overdrive unit (U.S. Gear or Gearvendors).
However, the guy I referenced earlier who was having problems with GM automatics was, IIRC, having problems with both 700R4's and TH400's. Again, I don't know the details there, and maybe his experience was an exception, but he regularly praises the old truck...except for the tranny.

Quote:
Glowplugs are easy except for two. Can be done in under an hour.
Ouch. I was able to do the glow plugs in my old van in a half hour; the only problem was trying to figure out the best way to get to the front two plugs (not a problem on the pickup; the van body made for space issues).

Quote:
Injectors are tight around the heater box, again, having the special short injector socket makes it easy.
Yes, but you mention needing the special socket to make it easy. All I need for the injectors on my 6.9l is a deep-well 1" socket, and they're right in plain sight. Heck, they're easier to remove than the injectors are on the OM617.

Quote:
Why is the fact that the injector lines running over the valve covers an issue? GM diesel valve covers are essentially glued on, rarely leak and since the lifters are hydraulic and therefore require no maintenence, why would I need to remove the valve covers on a regular basis?
To me, it's an issue because I prefer to leave as many other parts intact when removing something as possible, in order to reduce complications. You're right that the valve cover shouldn't need to be removed regularly, but if you want to inspect the valvetrain for any reason (or if something happens and the valve cover does start leaking), getting the lines out of the way just made for a few more steps in the process of removing the cover.

Quote:
You can indeed remove the injector lines from the pump and leave the pump in place. Start at the top and work your way around.
How do you get a wrench around the piece in the middle that supplies fuel to the pump? Or is the GM version of the Stanadyne pump different in that aspect than the Ford version?

Quote:
The intake manifold comes off with just 8 easy to get to bolts, and it is not in any way attached to the cooling system so why is this a big deal?
I remember more than 8 bolts on the 6.2l I took apart last year (I think there were either 2 or 3 bolts per cylinder), but maybe the 6.5l's different. You're right that it's not attached to the cooling system, but as I mentioned before, I prefer not to disturb anything more than what's necessary, and I see the design as making what should be an unnecessary step needed.

Quote:
Pumps usually last well past 100K, most will go 200K and some even hit 300K.
Do you by chance have any firm statistics on that? I'm not saying that you're wrong, but given that the 6.2l and the 6.9l use the same basic pump design, and given that there is a known flaw in said design that typically lasts about 100K miles (yes, there are exceptions to this) before failing and requiring pump replacement, I'd like to see how GM's setup was different, if it is.

Quote:
How many pumps do you expect to change? 25-30K per year of driving means you would possibly need to R&R the pump every 4-5years? Doesn't seem like a big deal to me.....
Then we differ on that. As I said before, I prefer to keep extraneous parts removal to a minimum.

Quote:
Regarding the water separator, it was installed after the electric lift pump but before the injection pump, so yes its there. Unfortunately the design of the lift pump allows water to pool in a low spot and corrode components. Installing a filter before the pump is one way to fix the problem.
Okay, fine. I honestly didn't know that, and a previous poster implied that one wasn't installed at all. My eyes bugged out when I saw that; I had trouble believing it. If you want to hold that against me, I can't stop you, but I don't think it's fair.

Quote:
I prefer to regularly use a diesel fuel additive to deal with the water, keep the system clean and improve the quality of the fuel. I have an all-diesel fleet and I have NEVER had a fuel problem.
Neither have I, and for the same reasons (I also try to stick to truck stops when on the road). I believe in using every possible method of preventative maintenance (in fact, I want to put a Racor filter/separator in the 300D).

Quote:
My GM truck is on its original injection pump and lift pump and you better believe I keep a close eye on the harmonic damper. Nothing wrong with brand loyalty.
Congratulations on both counts.

Whoever said I'm brand-loyal? I don't think that Ford marks the epitomy of American manufacturing; in fact, before I came to my senses and realized that I only needed one truck I was going to replace my van with a '92 Dodge D-250. Fuel mileage and registration costs led me to look for a small diesel-powered commuter car instead, and hence I got my 300D. I think that Ford and Dodge have their good points and their bad points, and are overall on par with each other.

Yes, I have a very low opinion of GM, and if you want to know why, I'll attempt to explain it. Part of it is, as mentioned earlier, my viewpoint that they made various engine parts needlessly difficult to get to. In addition, I have yet to see any ample proof that there was ever a model year after 1983 where GM had an offering that was, at least in my opinion, truly "better" than what Ford and/or Dodge had to offer, and when I see people talking about GM as if it's the only option available, I have a tendency to attempt to show the person that there are other offerings that are (again, in my firm opinion) a better choice for the person. I also don't think that independent front suspension belongs on a full-size 4 wheel drive truck (yes, my F-250 has an IFS setup, and I would be happy to ditch the IFS for a Dana 60 solid axle; let's not get into how I came to own my truck right now). I've also seen evidence that GM does a lot of corner-cutting on design and manufacturing. For this reason, I've seen interiors that were in a much more poor state of repair than they should have been, just as an example. BTW, GM actually issued a press statement a couple of months ago saying that their quality over the past 20 years has not been up to par, and have promised to make things better. I honestly look forward to seeing what they'll do...and I sincerely hope that they get it right this time.

(continued in next post)
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  #20  
Old 09-29-2003, 05:21 AM
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(continuation of last post; I didn't know that there was a maximum character allowance in an individual post )

In addition, I do have some straight-up anger towards GM. They did such an excellent job of alienating the American public to the diesel engine in the early 1980's that many people today still think that diesels are unreliable pieces of junk. Even if the 350 diesel were capable of a long, maintenance-free life (this is up for debate although I'm sure you know what my position is ), GM apparently did a horribly substandard job of educating the vehicle buyers regarding caring for the technology that most of them had never seen before. As a dieselhead who regularly has to explain to people that the diesel engine is not a piece of junk, I simply cannot excuse GM for doing this. Had they done more testing on the 350 diesel before putting it into normal production and then educated the owners on the engine adequately (or if they had not tried), I think the history of vehicles in the United States over the past 15 or so years would likely be much different.

Quote:
The new Duramax diesel, from what I understand is the premier diesel engine in the light duty truck market. It by far outperforms Ford and Dodge both in torque and horsepower. This engine has Ford and Dodge shaking in their boots. Pairing it with the Allison six-speed automatic transmission is just icing on the cake.
First, the Allison's a 5 speed, not a 6 speed. The 6 speed is a ZF manual transmission, which is actually the same tranny that Ford uses. Second, at the moment, the D-max doesn't outperform anyone. It's a constant war, and at the moment the D-max puts out 300 horsepower and 520 ft-lbs of torque. The 6.0l Powerstroke puts out 325 horsepower and 560 ft-lbs of torque, and the Cummins puts out 305 horsepower and 555 ft-lbs of torque. Furthermore, the D-max has aluminum cylinder heads, and while others may have different opinions, that alone turns me away from the engine (I wouldn't own an OM603 for the exact same reason; this is also why I have a 617-powered M-B instead of a Volkswagen diesel right now). Right now, Ford's on top, except that they're having serious problems with the engine (there was actually talk about a class-action lawsuit). GM will probably up the D-max's power in a couple of years, and Ford and Dodge will do the same.

Okay, given that it's almost 0230 and I'm coming down with something, I hope that was all coherent...I'll re-read it tomorrow and make any corrections. Until then, have a good evening.
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  #21  
Old 09-29-2003, 07:47 PM
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Believe me I am not a defender of GM in general, just in that I think the 6.2-6.5 motors got a bad rap. They were designed be Detroit Diesel for GM in the very early 80's. Primary considerations were good fuel mileage and decent power. They are very good at what they were designed for. Comparing them to Navistar and Cummins is really quite apples and oranges. The weights of the engines tell the story. The GM's weigh about 700lbs. Cummins and Navistar are over 1K.... The Cummins and Navistar are both deep-skirted heavy duty industrial motors that were never intended for light duty pickup truck use. It is somewhat suprising to me that the GM did as well as it did considering the original design intent. GM also really sucks at customer support, training dealer techs, etc. especially when it comes to diesels. Anyhoo, Cavitation is a known phenomenon that has occured in different heavy-duty diesel brands at one time or another over the years. Anti cavitation additives are very common and often just thrown in just in case or included in the chemistry of HD diesel coolants. Suprisingly the GM design never had a problem with it. As far as statistics on the Stanadyne pump life the membership on the Dieselpage seem to get 175-200K on a pump. Mine has 190K and since I can't seem to get the EGT's past 1000* anymore I think its past its prime. Still starts and runs fine so I am no hurrry to change it. Regarding the special tools. I use a squad of flare nut wrenches, crowsfeet, 15* and 30* offset combinations, special injector socket, and even a special injection pump mounting bolt wrench for pump work. Special tools are expected for some things and MB's are certainly one of the worst when it comes to this. My theory is the Stanadyne pumps are very easily damaged by water. Since the filter systems on US diesels are all inadequate, IMHO, and owners are not properly educated on how to care for diesels, most pumps die a premature death. Regarding the strength of the TH400, it makes a damned fine drag racing transmission as does the C6 and 727. None of them should have any trouble with a diesel. The 4L80E is the only 4spd OD auto transmission I am aware of that is being built to live behind 1200+hp "streetable" hotrod engines. Cost is not an object for the people who play with these types of toys so if the Ford or Chrysler trannys were better they would be being used. IMHO the GM trucks look better, ride/handle better than the competition of that era. While my truck has been suprisingly reliable and tows much better than I expected I didn't buy it for those reasons. Its comfortable, quiet, efficient and was MUCH cheaper than comparable Dodges/Fords when I bought it. Believe me if MB made a diesel pickup I would want one too. But since a GM/Ford/Dodge are all over $35K now I would imagine the MB at least double that figure. And GM didn't ask Isuzu to design their new diesel for them... They told them!! GM owns a controlling interest in Isuzu. Isuzu is also the worlds largest producer of diesel engines. If they say alloy heads are okay I tend to think they know what they are talking about. RT

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