Duramax head failure @ 500 miles

[Mr.B]

that's why most people use bronze valve guides instead of steel

 

[RobG]

I went over to the DieselPage forum after reading this topic, and there's a thread there about this thread.

Nobody there knows anything about any head failures, and are pointing out that so far, any failure reports posted here are always from "the friend of a friend," or something equally vague.

While I'm no Duramax lover, it would be very nice to be able to back this stuff up.

Rob


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2001. 5 RAM 3500 QC 4x4 ETH/DEE Silver/Agate 4. 10 USGear OD, Rickson 19. 5 Wheels, Edge EZ, SPA Guages, Psychotty, Firestone Airbags, Hellwig Rear Swaybar, Torklift Superhitch & Camper Tiedowns, Mag-Hytec Diff Cover, DD 4" Exhaust, US Gear Exhaust Brake, etc.

 

[Sled Puller]

Ditto, Rob.

The Duramaxes are holding up quite well compared to all the GM Diesel past fiascos.
(or they are being VERY quiet about it)

I want see proof so I can rip on the Chevy guys.

Just saying it is going to happen, or I heard it happened puts us right in there with the "Ford owns Cummins" crowd.
Gene

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1997 Cummins Dodge 4x4 "One Piece At A Time" Bombed & Amsoiled. Amsoil Premiere Direct Jobber, Member of: NRA Business Alliance, GLTDR, WANTED: Wrecked Dodges.
www.awdist.com

 

[rmrc]

From what I have read in various sources, there hasn't been many documented head failures with the Duramax. All in all, I hope that all of the Chevy and GMC followers have nothing but good luck with their trucks. They're paying the same amount or more for their Duramax's. Any way you slice it, when a person shells out that kind of money for a product, having it give you ANY kind of problem is unforgiveable!!!

Remember, we all do have one thing in common. We bought these trucks because we love Diesels! As for me, the only diesel I'll consider is the Cummins!!!

[This message has been edited by rmrc (edited 04-04-2001). ]

 

[Max340]

Originally posted by Mr. B:
that's why most people use bronze valve guides instead of steel

Guides are one thing, seats are another..... and they WILL fall out if the Dmax gets hammered too much.

 

[Mr.B]

How are the seats going to get "hammered" out. The valve springs on the DMAX probably aren't but about 90psi (give or take 10psi). The seats might loosen up because of the thermal cycling of the aluminum, but I seriously doubt it since nascar runs extreme compression ratios and very stiff valve springs and I don't ever hear of "hammered" out valve seat problems. And one final question, when you hammer something, don't you hammer it in instead of out?

 

[JohndeereG]

I test drove the DM when my father-in-law was looking to buy a new ride. If we have 11 quarts of oil and the powersmoke has 14 (I think), what is the pan capacity of the DM. ONLY 6.

Last time I checked diesels run on the dirty side. 200K mile engine life... . I doubt it! #ad




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2000 SLT QD Cab Two tone Green/silver, Geno's MEK, silencer removed, Rhino liner
Our Antique Tractors

 

[Bob Riley]

Guys, some of you seem real quick to put down the DM. Personally, I hope it's the best truck ever produced. It only raises the bar for Ford and Dodge. I would like to see FOrd worry about Chevy's truck. Right now, they all laugh at it as a competitor, so there is no reason to worry or try to improve if you already have one of the two best diesels on the road.

Yeh, it would be nice to see proof of something like this though #ad

Bob

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DiabloSport Dealer

 

[Dr.Evil]

MAX 340 is right. Valve SEATS are either made out of investment cast Stellite or are induction hardened, then ground and lapped. They are exposed to the actual comb. gases which are 4000 to 5000 Deg. F. as they blow past the valve and seat. VALVE GUIDES on the other hand except for the very short portion that extends into the exhaust port is basically a "BUSHING" that supports the valve. Two totally separate parts of the cyl. head. DENNY... ...

[This message has been edited by Dr. Evil (edited 04-05-2001). ]

 

[WCrovo]

I feel the same way as some of you do. I am not chomping at the bit to see any issues with the Duramax. I could of gotten the GM but I chose the Dodge/Cummins and am happy with my choice. I don't want anyone to have problems with their ride but I will say better them than me. Durmax(Isuzu) or the Powerstroke(Navistar) are not for me. It dose seem to me that some of us on the TDR are anxious to see catastropic failures on the comps stuff. I would keep quiet if hearsay is all the proof you have, sounds childish to me. I do love the Cummins and wouldn't trade it for all the farms in Cuba.

 

[Sled Puller]

OR... ... BOB, A FATE WORSE THAN DEATH!

The idiot Germans decide to install a V-8 Diesel to copy the other two goombas. NOOOOOOOOOOOOOOOOO!!!!!!!!

Give me inline 6, or give the Fords and Chevys death!!

Gene

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1997 Cummins Dodge 4x4 "One Piece At A Time" Bombed & Amsoiled. Amsoil Premiere Direct Jobber, Member of: NRA Business Alliance, GLTDR, WANTED: Wrecked Dodges.
www.awdist.com

 

[Max340]

Originally posted by Mr. B:
How are the seats going to get "hammered" out. The valve springs on the DMAX probably aren't but about 90psi (give or take 10psi). The seats might loosen up because of the thermal cycling of the aluminum, but I seriously doubt it since nascar runs extreme compression ratios and very stiff valve springs and I don't ever hear of "hammered" out valve seat problems. And one final question, when you hammer something, don't you hammer it in instead of out?

Ok, lets start with the fact that NASCAR swaps heads every couple thousand miles. Thus, there are few bad seats in the engine, and they get checked often. Second fact: NASCAR DOES lose heads to valve seat failure. So that eliminates the "race heads do fine, why won't these?" argument.

You are exactly right, the seats may loosen up due to thermal cycling. Particularly if too much heat is made by power upgrades. If it gets loose, the hammering will occur when the valve closes. Unfortunately, that hammering is not going to tighten the seat, but will distort the head where the seat is pressed in. This distortion increases the hammering until it destroys the head.

Sorry, but its a fact of life with aluminum heads. Thankfully, I was smart enough to buy a proven engine with good design, even if it is initially lower in power.

Bob, I am quick to put down the Duramax because it has proven design flaws. How well they work out in the Duramax is subject to real world experience. However, I seriously doubt the expansion properties of aluminum has changed significantly since the Monza engine, or the Mopar 2. 2, or the Caddy 4100, or the Escort 1. 6/1. 9. Thus I have to conclude in the early going that one of "those" diesels will never be in my ownership due to its design. It is, in my opinion a far lesser engine than the Cummins, and far lesser than what guys are paying for it, and about right for GM's traditional "disposable design".

MGM, we agree again. I firmly believe I drive the best engine on the market today, and for the foreseable future. Am I happy to see the others fail? No. Would I be surprised if they did? No.

 

[Brandon]

how did the head failure happen at 500 miles???????????????

I figure the head failure occurred when the soon to be owner signed the check for the truck... ... ... thats were the real head failure was
B... ... ... ... ... ... ... .

 

[CannonBall]

Any engine made today can experience this kind of failure internally or externally including the head and furthermore including the Cummins.

I am sure that the new Isuzu is designed to go further than 500 miles before it needs heads or head gaskets. There is always going to be cases like this, if in fact this engine did suffer head problems, with any engine.

Having said that, I have to side with 340. Aluminum heads are just that, aluminum. I will reinterate again a discussion I had with an engineer, he stated " AS MUCH ALUMINUM AS POSSIBLE SHOULD BE REMOVED FROM THE COMBUSTION CHAMBER AREA".

Furthermore, he stated there was no advantage to aluminum heads on a diesel other than a weight savings. This was not only a single engineers opinion but a combined opinion of a group of engineers through studies of diesel engines with aluminum heads.

Whatever the Isuzu may end up being, good bad or indifferent, I will stick with 340's train of thought, there are design flaws with the Isuzu that cannot be overlooked.

[This message has been edited by CannonBall (edited 04-06-2001). ]

[This message has been edited by CannonBall (edited 04-06-2001). ]

 

[Mr.B]

Max340, I have one more question for you, you said, "I am quick to put down the Duramax because it has proven design flaws", why didn't you call up GM and tell them about the flaws that were proven to you. You must know something they don't?

 

[Bob Riley]

I just figure that the engineers at GM and Izuzu hava a little more info than we do about expansion properties. They can't be that stupid. But we are talking about GM #ad
Seriously, to think nothing has changed since the Monza days is very cloed minded. They have come a long way with designs of composite materials and mixes of metals.

I'll give you an example of what I'm talking about. Ford mustangs now use a composite/fiberglass type of material for the valve covers and the intake manifold. You don't hear of problems with this design, but some stuck in the old ways would say, "that's plastics" that stuff wasn't any good in 1960, how could it possibly hold up?

Back to the Dmax, this engine has been used in Europe for two years now in street sweepers. No, it's not a truck pulling weight, but that was just one example of the testing grounds. I really doubt there are the problems that people are rumouring about.
I too would like to see the prooven faults of the Dmax, heck, there aren't that many on the road yet. If they were already prooven to be a peice of junk, then most have already failed. It just doesn't make any sence. Even Diesel Dynamics or somone like that said they heard rumours, but said no one could back up any of them.
Bob

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DiabloSport Dealer

 

[Max340]

Mr. B, the design flaws I speak of are things that have failed in the past under various conditions, design parameters, and levels of monitoring/care. It is stupid to think that aluminum can ever have comparable expansion rates to iron, and as such, several things have to be taken into consideration. 1) The head gasket itself has to withstand a stress factor that pulls opposite sides of the gasket at different rates. 2) Head bolts must be able to maintain an even holding force with both vertical and horizontal expansion changing this force each and every heat cycle. 3)Valve seats can prematurely fail due to this difference in expansion rates.

Sorry, but NONE of these things works real well in a gasoline engine. I predicted the second failure of a Monza engine to within an hour of its demise. I've had one Mopar 2. 2 warp its head, and seen countless others puke their head gasket. I worked on trying to rebuild a 4100 that was literally falling apart at the seams (more the fault of my employer on the reassembly) but initially puked a head gasket. My experience in the field tells me that a heavy duty long life engine avoids the aluminum/iron stress point.

Bob, its true, they probably have a bunch of info on the expansion properties. And maybe the Dmax goes the distance they say it will... . about HALF what a Cummins will for just over $1000 more in retail option cost. Thats strike one.

I never said technology had not changed. But its safe to say that aluminum and iron have not changed enough that they now have the same expansion rates. Until they do, I'll sit out the testing phase of the Duramax. Thats strike two.

The aluminum heads are supposed to help this engine, I am guessing it allows the engine to heat up more quickly and thus lowers emissions. I don't like an aluminum head for the side effect... it takes more fuel to KEEP it warmed up. Therefore, less efficiency. Thats strike three.

Next, ythe Dmax likes to rev for its power. Thats fine. However, at the compression levels in a diesel, its looking for trouble and stress o nthe rods and crank. Yeah, I know the NASCAR motors are running high compression... but not 17:1. If they could make power and keep things together, don't you think they would run that sort of CR? Sorry, I just don't buy it. If you buy a diesel, its for low end grunt and torque at a lower RPM, not to race around town. Some will now counter and say well, you can do that in a Cummins. Great. Thats terrific. That shows how much more the Cummins can do well than the Duramax which I think will see its share of sellers within a couple of years... and those guys will find a Ram/Cummins.

Regarding the intake and valve covers of the 'Stang. Terrific, plastic valve covers. Sounds cool. And it is when compared to a combustion chamer. Same with the intake manifold. Did they mention the material the plastic manifold was bolted to? I'll bet it was aluminum. (I know it was. ) The plastic can be engineered to have the same qualities as the aluminum, and thus, no problems. BTW, Those new 'Stang motors are not exactly the easiest to try and rebuild, since the entire block takes a new "shape" when it is unbolted from the heads and crank girdle. Just gotta love the properies of aluminum.

You are correct, the Duramax has yet to get enough out there to prove anything. However, most of us are skeptics from fact, not rumor. I'll await the reports backed by facts on head failure on the Duramax. I know they will show up long before I have to do more than change oil in my Cummins.

I'd wager by... ... October, just after the new model year, the Duramax starts making news. Hopefully for all those guys that bought one, I am wrong.



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Y2K 2500 QC Sport 4x4 LWB
72 Dart 340
89 LeBaron GTC 2. 2 TI

 

[HEMI®Dart]

Max,

What kind of aluminum do they use to make Nitromethane HEMI® heads & blocks? This type of aluminum must be MUCH stronger than what is seen on passenger car heads.

Kieth Black says "Cylinder bores have retained roundness to within . 0002” after several runs" (6000 HP)

An old MP catalog says the heads have 40,000 psi tensile strength?



[This message has been edited by HEMI®Dart (edited 04-06-2001). ]

 

[Max340]

Hemi, its safe to assume the type of aluminum alloy used in the race engines is not significantly, if at all, different from the cylinder heads on typical passenger car engines. In fact, it might be more stressful for the heads on the gasoline powered engines because typically the fuel used in race engines burns cooler (thus you need LOTS more of it) and will not stress the aluminum or burn it as much as a gasoline engine. Any facts to the contrary are gladly accepted.

Keith Black no doubt uses a steel/iron alloy for the cylinder bores. Thus roundness or taper in the cylinder is irrelevant to how well the aluminum holds up, since aluminum is not used in the sleeves.

Sure, I'll bet they do have an unreal tensile strength. The key here is, how was that measured? And what does tensile strength have to do with expansion, warpage, and head gasket material? IOW, if I have a grade 8 bolt, and I bend the thing, it still has the same sheer resistance. But is it going to do the same job it would have before I put a bend in it? No.

The tensile strength that MP mentions is the ability of the head to keep its shape when torqued down. IOW, it is constructed internally to put an even load on the head gasket, thus enhancing sealing properties. Thats terrific. Mopar has a very good history of the W series race heads standing up to racing conditions. But as I said before, the real test is the gasket itself. Thus no matter how strong the head is, it will still expand and contract. And it may even warp a bit, but thats a risk factor, not a guarantee either way.

Diesels are a different beast than a spark ignition engine. At some point, an SI engine will be at its limit of air/fuel amount, and that is always at the same ratio. Thus the temperature is easily controlled, and the temp parameters under which it operates are fairly slim.

Go to a compression ignition engine, and suddenly the rules change. The engine gains and loses power ON PURPOSE through the addition and reduction of fuel in the air. There is no set A/F ratio. It will take as much as you can stuff into it (well, there may be guys hitting the limit, but for reality purposes, its beyond most uses). Temps range over 1000 degrees. CR is way up, and the cylinder pressure is NOT relieved by a wild cam with early "intake valve open event" or overlap to lower the pressure. IOW, MUCH more stress on the head gasket, and the head itself. This is why a diesel has a much heavier block and head to begin with.

The ONLY thing I see in the Duramax favor is the fact thta Isuzu had a hand in the design. Their rep worldwide is very good, and they are the largest seller of automotive diesels in the world. However, I stand by what I have said. I conclude by saying that GM has probably done what it seems to do most of the time, and what its founding fathers felt was good marketing. Don't sell a vehicle that will last forever, sell one that is good for now, but will make the customer come back for another later.

I don't know about you, but most of us out here don't like the idea of a vehicle that cost more than our parents last house did crapping out at the 200k mark. Thats what GM says they figure is the limit. I'll pass. In more ways than one. I bought my last truck last year. GM buyers will spend at least $80k before they buy their last truck.



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Y2K 2500 QC Sport 4x4 LWB
72 Dart 340
89 LeBaron GTC 2. 2 TI

 

[Mr.B]

Max340, first of all you never answered my question. You rephrased your previous statment from, The Dmax has proven design flaws" to "things that have failed in the past". Second, you keep referring back to monzas and a mopar 2. 2. We are in the 21 century now. Don't you think anybody else learned anything from these mistake? Or you were the only one. After all these years of racing engines being built with iron blocks and aluminum heads with NOS or blowers on them and 6000 horsepower Top fuel cars and nobody has learned anything. And somehow you believe that the Dmax is under more stress than these engines, whatever. I am glad you are not designing engines because after your first try, a monza or some other POS, you would have gave up and said it can never be done. We have come a long way since then, you may want to look around and see! It wouldn't suprise me to see an all aluminum diesel in the near future, all this aluminum is for less weight to gain gas mileage. It's not like aluminum gives you an extra 100hps because you used it somewhere.