View Full Version : duramax heads
Say the engine overheats what will happen to that alluminume head??will it warp or crack??
millietom
05-03-2002, 19:00
Hope this thread lasts for awhile. Ford, Dodge and even GM salesmen that can't get enough Duramax trucks to sale tell horror stories about Duramax head failures. I havn't heard a one that can be backed up.
Tom
Also i forgot to add why did they change heads from the 7.8 liter that goes in the cab overs.I am still not convinced about the new direction of GM. and if i had to buy one right this moument i would lean to the 7.3 from listening on hear there is still way to many things going wrong with these $5K engine and$4K trany.I think they put to much time into the ugly advalanch.
The aluminum heads warping/cracking issue is old, as a matter of fact- there is not an issue that exists (except on the Anti-GM sites). The few known PROVEN problems should be chalked up to any normal mechanichal failure- let's say just like a battery going bad in the first year due to some manufacturing problem, things are going to hapeen no matter what. The Duramax was thorughly tested including some extreme hot/cold water being introduced while at max load- hot engine, with excellent results. I think you will find more proud, pleased owners that you will find problems. These diesels have already begin to prove themselves, there are many out there with over 100,000 miles, and one that we know of over at putc thats over 300'000 already.
Here we go again. OK, let's all come clean:
If the engine overheats, the mysterious metal "ALUMINUM", which the human race just discovered and nobody really knows its properties, will cause the heads to melt down all at once.
Molten aluminum will cascade down into the cylinders, and since the engine is running, the pistons moving up and down will spray a hellish fog of superheated aluminum mist all through the engine compartment, and into the air conditioning ductwork. Then the AC and heater vents will send gouts of this sun-hot elemental aluminum vapor into the faces and onto the bodies of all passengers, causing them to perish just like the melting Nazis did at the end of the "Raiders of the Lost Ark" movie.
GM and Isuzu are naturally covering up a number of these events, but there is a secret technical bulletin out detailing the problem. With "Aluminum" being so mysterious, dangerous and expensive, no wonder Ford and Dodge don't use it on their engines; they are smart. How stupid GM and Isuzu are. All these melted trucks and people could have been avoided by using Cast Iron.
Can I have an "amen", my brothers?
;)
[ 05-04-2002: Message edited by: xwing ]</p>
Amen brutha, I now see the light! :D ;)
Third!
[ 05-03-2002: Message edited by: motovet ]</p>
But, but... so called expert "Mr. Truck" is spreading these "facts" on his website ( www.mrtruck.net )
"I talked to people from all around the country and I'm surprised at what I hear. The happiest Duramax owners are the ones who don't pull a trailer with them. I've had people tell me of broken crankshafts, transmissions and lots and lots of replaced head gaskets. The aluminum head problem has to be addressed. Aluminum expands at twice the rate of cast iron. You put the two metals on top of each other, throw in the heat and compression of a diesel engine and what do you thinks is going to happen. I thought 2002 was the year of the Duramax, but they end the third quarter with declining sales number, with Dodge staying the same and Ford picking up. I will be looking for improvements in the 2002 Duramax and report them."
On a RV forum, this info was the main reason someone claimed they decided to buy a F**d!
They wouldn't listen to the happy Dmax owners that posted. The web is impressive isn't it? Anyone can spread lies at the speed of light!
AlaskaDmax
05-04-2002, 00:11
Fourth...
I had to run an errand today, parked the truck and went in. An older guy comes walkin up and asked me, rather excitedly, about the truck.
We started talkin and he just comes right out and says..." Yeah, you might like that engine, but you couldn't convince me to buy one....they are having tons of problems with that engine...and the Allison, it is a peice of crap." Blah, Blah, Blah
Where the hell do these people come up with this crap? :confused:
DmaxMaverick
05-04-2002, 00:46
Blah...Blah...Blah...
Buy the furd. You'd lose too much sleep worrying about all the 'problems' if you bought a cheby.
That would leave one more Durmax for someone that may really appreciate it.
Not flamin' ya. Just stating the obvious.
Xwing, I have an Ex wife... So I was wondering about this line. "causing them to perish just like the melting Nazis did at the end of the "Raiders of the Lost Arc" movie." Could this be done on Q?
Or would she have to ride around for a while...
LOL!
PS You forgot to mention that if you use one of those 1 million candlewatt powered lights, and shine it just right you can see what kind of Beer cans the heads are made of...
Idle_Chatter
05-04-2002, 06:52
I love the F**D and D***E fanatics that are _STARVING_ for bad DMax info!!! They hear and believe all the bull, and everytime I speak with one they want confirmation! I was trailering my junk up from Florida to Maryland and happend to be across a fuel dock from three guys in a bright red Powerstroke CC F350. As I was chcking my oil, one happened to wander over and ask, "you like that Duramax?" I said "Naw, I don't like it" and the other two crowded up to get the dirt, and I said "I *LOVE* it!" Man, did they look disappointed!! I practically _chased_ them back into their truck as I told them that it pulls like a gorilla, runs like a scalded dog, that I get 20 mpg unloaded and that I was getting 17.4 mpg that day with a loaded bed and pulling a trailer! The only thing that would have made it sweeter would have been the opportunity to follow them out onto the interstate and to out-accelerate and pass their empty bed ass with my trailer hooked on! If you aint got bad news, F*** and D**** guys don't want to hear it! :D
So the duramax will have no more problems than any other diesel engine.Another question why is it that the 7.8 engine has cast heads and not the aluminume one like the duramax? and if the duramax is far more superior why have they not changed over to the aluminume in the 7.8.Don't get me wrong I have a 6.5 and love my chevy but the way Gm does every thing else :rolleyes: They are detiot diesel and it took them this long to come out with the duramx and then they had to partner up with Izzue? WE had a 6.2 that was junk so if I have any reservation on this engine that is way and to pay that kind of money for the dura/allis combo :( will the price go down some now that they are on line 2nd year probaly not.Look at the new HD line 4500's and up no 4x4 for first model the one that every one wants who does GM listen too>>..
Although the 7.8 is a "Duramax", it really has no relation to the 6.6 at all except that it is an Isuzu. It's possible that since the 7.8 is a straight six, the length of the head might make it a poor choice for aluminum. The longer the length, the more change in dimension. I'm sure there are many other reasons. I also believe the 7.8 was developed before the 6.6 went through it's development. There is an entire category devoted to the 7.8 on this forum. As some questions there.
On the failing heads issue. You can go to any board and look up warped and cracked heads and you will find them. Navistar, Cummins and the previous GM 6.5/6.2's have had warped or cracked heads at some point. You can also go to any other information source about any other engines including gassers and you will find head gasket problems, cracking and warping and guess what? Many are cast iron heads.
After two years, there are no significant problems with the heads on the Duramax 6.6
If it would ever become an issue, you can be sure there would be real, substative articles and reports that aren't just forum "gossip".
Does anybody out there have a verified, honest list of reliably sourced articles or papers on Dmax head problems?
Post them here and we will read.
Mike
What ta hell is this crap............
cat320,
What exactly do you put your carcass in and tool around in work or play?..............GM and ISUZU were partners before the D-MAX came into play..........May I ask have you ever driven or ridden in one off these "HEAD POPPERS" ?......I carry a spare set just in case....... :D :D .......
Attending to the needs of the stranded FORD AND DODGE vehicles is the C7500 Pro-Rollback's Duramax 7800 diesel engine. The OHC, 6-cylinder powerplant produces 275 horsepower at 2400 rpm and 800 lb-ft of torque at 1450 rpm, more than enough power and torque to rescue any stranded FORD OR DODGE owner.
Now can I ask you a couple questions?........
Why is the sky blue?
What came first the CHICKEN or the EGG?
This should keep you busy instead of worrying about us enjoying our 8'th wonder of the WORLD our D-MAX'ES...
MAC
tongue.gif
[ 05-04-2002: Message edited by: mackin ]</p>
The biggest advantage to the Aluminum heads was weight. Critical for a pickup. Not so important in a medium duty truck such as the ones that the 7.8 comes in.
Medium duties don't fall under the same emission standards as the pickups so there was nothing to be gained from using the Al on the 7.8.
Weight isn't much a factor in a truck that already weighs in at 10-13,000 lbs.
Nobody has said this officialy but I would imagine the Aluminum contributes to the quietness of the 6.6. Again not a factor for the med duty.
Aluminum heads are more expensive to produce than cast iron. I don't know if the 7.8 uses a one piece head or a segmented head. If it is one piece then the different expansion rates would be a bigger factor for a head that is close to 50 inches long and would probably require going to a segmented design.
The 6.6 uses aluminum because there is much more to be gained for that application than using Al on the 7.8.
From what I've seen and heard so far the heads on the Dmax are never gonna be any more of a problem than the heads on 5.9BT.
[ 05-04-2002: Message edited by: Wally ]</p>
Hey Wally, what 1/4th of the four corners are you from anyway? Just curios as it is welcome to see anyone from the lower right hand state.
Later
Seven
billnourse
05-04-2002, 10:55
What's with all the questions about the realibility of the D-Max??? Isuzu had been manufacturing diesel engines since 1936, and is currently (so I've heard) the largest manufacturer of diesel engines in the world. Seems to me that they must be doing something right, and the D-max is no exception.
Bill, lower right corner
7mmSTW,
I reside right around the corner from Mr. Nourse in Aztec. Born and half raised in Jal, the opposite corner of the state. :D
[ 05-04-2002: Message edited by: Wally ]</p>
slapshot44
05-04-2002, 19:47
Why are we even dignifying this subject again...
If an engine overheats severely enough, guess what, the heads (as well as the block) will warp and/or crack, no matter what material they're made of.
I'm tired of hearing about all of these internet experts commenting on how worthless aluminum heads are on hard working engines. I just got back from a local car show. Saw an old buddy who has a 64 GTO drag car (at least most of it is still a 64 GTO.) He just broke into the 9-second range with the original frame still underneath it (a funny-car frame is being constructed for it.) He figures he's over 800 hp right now with it running on injected alcohol. He fired it up for me (talk about gathering a crowd!!) Guess what, he's running custom ALUMINUM heads on a cast iron block, EGADS!!! 15:1 compression ratio also. I asked him if he has had any problems with the aluminum/ cast-iron match-up. Nope. No special gaskets either.
Come to think of it, a huge number of people are running aluminum heads on cast-iron blocks in the muscle car venue. Are all of these people crazy? NO. Are these people having problems keeping their heads sealed to the block? NO. Are these people having their heads warp and crack? NO.
Aluminum heads are a non-issue. As far as I remember reading, even if every so-called Duramax head failure reported on the internet is true, if you compare them to the number of engines out there, the failure rate is still well under statistical probability (every mechanical device will have some failure rate, the object is to keep it as small as possible.) And we all know that there have been very few (and I don't think any of them have been due to warping or cracking) ACTUAL head problems with our engines.
So, cat320 I hope my first paragraph answered your original question: "Say the engine overheats what will happen to that alluminume head??will it warp or crack??"
Now, may I ask you, what is the actual purpose of posts like this? If you just want to stir-up trouble over non-issues, why not do it on one of the boards where the members are more gullible. This board hasn't shied away from discussing actual problems that some have had with their trucks. EVERY brand has its own share of problems. Lets keep it to actual problems, not hype from the internet (internot?) community...
[ 05-04-2002: Message edited by: slapshot44 ]</p>
Mackin, I was asking the question becuase we where just at the boston truck show and my brotherin law a diesel mechanic said that the aluminume was a good head but ,he asked what if the thermostate went bad and it read lined in turn he said your head would be junk from over heating.And as far as Isuzu i have seen trucks with there engines that have gonn bad with no millage on them and as the price of this duramax engine is they follow suite as being very pricy.having a much quieter engine does not bother me just let them get more Hp and towing power at a lower price tag .
If the Duramx and Alisson are so bad, how come GM's truck sales are up, along with Chrysler Products and the F--d's are down.
Is this guy for real??
slapshot44
05-04-2002, 20:43
If I remember my physics classes correctly, an aluminum head should be able to bear an overheating problem better than a cast-iron head due to its higher heat-conduction value. When an engine overheats, it will see greatly uneven heat patterns, localized at the combustion area, gradually spreading throughout the metal by conduction (heat flows from a hotter to a colder area.) It is the uneven, localized heat pattern stressing the metal that causes warping or cracking. Since aluminum has a conduction value about 3 times that of iron (if I remember correctly), the aluminum will dissipate, or "even out" the heat stresses much faster than cast-iron will, which should allow the aluminum head to survive an overheating condition better than the cast-iron will. In fact, this is one of the "down-sides" to using aluminum in a high-performance engine, since it is the heat produced by the combustion process that actually does the work in an engine. With aluminum being such an efficient heat conductor, more of the heat of the combustion process is removed from the combustion chamber before it can be put to work. But the benefits of aluminum heads generally outweigh this inherent disadvantage.
So, if you're genuinely interested in why some crazy engineers would bother using aluminum in an engine, ask away. There are more than a couple of engineers who frequent this board that I'm sure would be glad to try and explain why certain things might be done the way they are. I'm sorry if I flamed up on you to hard in my previous post. It just seemed to me to be a non-specific, general jab at a way over-done subject.
BTW, we would all like to have continually improved products for continually less money, and a zero-failure rate, but it will never happen in this Universe... Besides, if things never broke, what would all the mechanics (like your brother-in-law) in the world do? Also, there is a reason why engineers put all those gauges, warning lights, and information centers on our vehicles... so we can turn off the key BEFORE our engines melt!
sonofagun
05-04-2002, 20:46
cat320,
From the tone of your post I'd say go buy a F*** or D****. You'll be much happier not worrying about the coming of the great flood. Not trying to set you apart from those on this forum but you seem to have your mind made up and looking for an argument. We have faith in this truck, its motor and transmission. If you don't may the force be with you, but move on!
Bob
No,I'm not looking for an argument.All I did was aske a sipple question that was seconed by another person right after my first post .All of our trucks are gm ecxept for one ,we had the first diesel that gm put in a van the 6.2 had many probelms with it.I have a 6.5 no problems yet except for the injector pump.It has just been a rash of problems with gm on many differnt trucks and cars.And like it was said nothing is perfect in any one of the big three.And it's true they do put the gauges in there to be looked atAnd I thought it was about time that gem came up with a decente engine would like it to be louder .
01_Duramax_Dually
05-04-2002, 23:03
OH MY,
I came home, parked my Truck out front, My neighbors came running over and asked what that Molten Silverish material was running down my Driveway....I replied calmly...
"Oh that is what's left of my aluminum heads"...I said "It happens all the time".."I have 10 sets in my garage" "I have the block studded now and just throw on a new set and just run the wing nuts down and we are good to go" I replace them every 300 miles, sooner if I tow"...I also have 4 Allison tansmissions in my shed..Those go out every 1K miles....LMAO...HAHAHAHAHAHAHAHA
I figure next will be all the posts about how defensive we are about this subject....
This aluminum material stuff they just discovered is some pretty amazing stuff... Wonder if anyone else will use it with a cast iron block...Hahahahahahahaha
Enough already...find something new to talk about..If you do not want to buy a Duramax because all of your metallurgical knowledge tells you it is a bad thing...then go to the other pages and buy the other stuff, choice is yours...
01_Duramax_Dually - Wing nuts? How do you torque those? Is there a special wrench for that?? OMG, you guys are so funny! LOL
:rolleyes: :D
Cool, I have spent a little time in the Aztec/Bloomfield area myself. We try to make a trip to Navajo once a year to do a little fishin'. You gotta love pullin a load up the dam. I spent a weekend at Gubernador this year removing brain stems from deer checking for Cronic Wasting Disease. Neat country up your way.
Later
Seven
P.S. I know this is off topic from this thread but I for one feel that I don't need to bother with the subject. I aint worried :rolleyes:
cat320, just like any car, truck, bus, etc,etc, if the engine overheats you should have the common sense to shut off the engine before any major damage occurs DUH.
mackin, I like your response to this non-sense. Not only did the Juice make your truck a rocket, but it also made you a good judge of character smile.gif .
Steve.
Cat320 ~ Valid questions that I've asked myself. Most have already asked and have come to the answers thats right for them. Like I'm a lil' apprehensive about this dawn of a new century tech invading even the simple stuff that used to be my realm. Unlike this new techy stuff, aluminum heads/other engine components have been around for many decades. As a matter of interest, my Dads '29 Cad (I'm dating myself) had an aluminum crankcase. The water jackets (read cylinder banks) had a knurled knob front and rear and after loosening, one could lift the the cast iron head/cylinder assy right off the case and leave the rods and pistons dangling :cool:
When someone is shelling out 40 big ones to wait in line for six months to purchase one of these '-- yet to be proven--' duramax's says a lot in itself. I find it hard to believe that kind of money comes easy for anyone ~ I know it doesn't for me. Skeptism of something that one personally see's as unproven/understood/otherwise feels uncomfortable about for any reason is pretty much normal. I recall in my youth, I asked Dad to spring for some contact lenses his response was "if God wanted you to have contact lenses, you would have been born w/them" ~ which left the question: "so I was born w/metal frame glasses?". ;)
In summary, a cracked/warped head is a cracked/warped head regardless of material. It behooves us to be cognizant of the health/well being of our engines ~ regardless, to avoid high cost repair bills. Every issue/thing will have nay sayers ~ research and come to peace w/yourself on the answer that is right for you. For me aluminum heads are a non-issue. I know that if I'm wrong ~ I'll be more than happy to join in a class action for resolution. ~ odoh
[ 05-05-2002: Message edited by: odoh ]</p>
billnourse
05-05-2002, 10:24
Seven,
My D/A will pull the 20 ft. Astro to the lake faster than it is safe to go . The crappie and smallmouth ( up to 4#) are really getting started and I'll be headed up tommorrow. This is great time of year for Navajo. Maybe I'll see you there sometime.
Bill
We were up there for Thanksgiving with our 36' Coachmen trailer and the D-max. We had to really watch it going up the dam as we could go up Way too fast to be safe smile.gif . Our 95 6.5 would top it @ 45mph. My Grandpas old 6.9 Ford ran about 3mph (no joke) up that hill with the same trailer. All I can say is diesel technology has sure improved in the last few years. The neet thing was that we didn't even melt our heads!! For all those worried about what the heads are made of. Have you stopped to think what they make pistons from? :confused:
Later
Seven
The other day at a filling station a D***e driver asked me about the D'max aluminum heads. I told he how pleased I was with mine and that I felt that there was too much incorrect info about D'maxes going around. He didn't seem the least bit convinced until I asked him.... If F**d and D***e aren't fully aware that when it comes to pickup diesels the D'max is state of the art, why are they racing to ugrade/redesign their engines in the hope of matching or bettering it? :eek:
slapshot44
05-05-2002, 13:17
Here is the correct procedure for tightening a wingnut to the proper torque setting:
1. Place tongue between teeth
2. Grasp wingnut with fingers
3. Twist wingnut until teeth bite down on tongue and cause an "OUCH" to be spoken.
4. Wingnut is now torqued to correct specification.
:D
tonyskid
05-05-2002, 19:08
I know how we can tighten up those wing nuts, like my 13 year old always says, "SHOULD OF USED A GATOR GRIP"
Smart A$$ Kid
Wow you guys,Well I'm not an engineer nor would i want to be .Unless i got all the money that they make doing nothing to buy these 40K plus dollar trucks.Very mad people here for just asking a question sorry that I could not ask it like 2 years ago when before the first truck came out like the rest off you people.you guys that are upset with me most likely don't use your trucks for other than going to the lake or something not for like pulling bobcats or dumping dirt or for work in general.Oh by the way I always keep a spare head around don't you??? so if you guys are done bashing me for asking a question that no one in my area has gotten yet,and yes you could get in a class action if something does go wrong but You could be dead by that time as i just got one from my old truck from 7 years ago.
big dipper
05-05-2002, 19:16
I don't think I quite follow the last post. Never mind, I see he is from, like "STONE"-ham. :rolleyes:
Sorry, I couldn't resist.
cat320,
Say you overheat ANY engine and let it run till it just about siezes. What will the heads do? Warp or crack?
How bout this one....
How do you pronounce the capitol of Kentucky,
Loo-ee-ville or Loo-is-ville?
well the piont i think that my brotherinlaw was trying to make is .wen the gauge reads hot it's too late for the alum. head verses cast.Well enough said on this i guess
D-max Man
05-05-2002, 20:33
The Duramax has some design features that help keep the heads safe but nothing is completely fail safe.
For example, if the engine starts to overheat, a warning lamp will light to get your attention (Look at the gauge silly ;) ). If you ignore the lamp, a buzzer will sound and if you still keep pushing it the engine will shut off the fuel every other revolution and only pump air through the cylinders (4 cyls. fire on this rev. and the other 4 on the next) to try and cool her down. If you still don't stop it will shut the engine down and you get the repair bill. :eek:
[ 05-05-2002: Message edited by: D-max Man ]</p>
matt-max
05-05-2002, 20:50
i pronounce it frank'-fort.
slapshot44
05-05-2002, 21:29
Wow cat320, I guess you didn't even bother to read my post that I spent so much time trying to explain to you about aluminum's greater heat conduction potential. As someone else pointed out, the pistons are going to melt a hole in themselves way before the head will melt down. A piston can't dissipate its heat as well as the head can. And IIRC you can't buy a cast-iron piston. :rolleyes:
And in regards to (quote) "Well I'm not an engineer nor would i want to be .Unless i got all the money that they make doing nothing to buy these 40K plus dollar trucks." Don't worry, I don't think you would ever become an engineer... even IF you wanted to. BTW, if there weren't any engineers, guess what, you'd still be riding a horse as there wouldn't be any cars or trucks (not that there's anything wrong with riding a horse, love it myself.)
Please tell your brother-in-law to stick with the wrench turning and leave the engineering to those who don't use their "spare" head to do their actual thinking with. Running your engine to the "hot" reading on the gauge isn't going to hurt an aluminum head any more than it would a cast-iron one. I don't think that you are interested in an answer to your question that doesn't agree with the ignorant hype being spread around the internet by the mis-informed. If you want to be ignorant, please limit your browsing to those boards frequented by the ignorant and opinionated.
OK, now enough has been said...
Below is a quote from More Power's recent post:
http://forum.62-65-dieselpage.com/ubb/ultimatebb.php?ubb=get_topic&f=3&t=003000
"The Duramax 6600 will begin its 3rd model year in just a few short months. In all this time, I have yet to hear of a (confirmed) aluminum cylinder head or head gasket failure."
I think that says it all.
Guys, please be more civil and cease the nasties...
slapshot I asked an honest and simple question and all I got from some was a lot of sarcasm .Yeah we would all be better off with horses less polutents in the air and I have had my fill with engineers and arcitects tha thing they know ther s**t. and have been proven wrong.But not all of them are that bad so I am really prefering to the ones that messed me up on jobs.My brotherinlaw works on the big rigs and not these little trucks so there engines are mostly cast .I did read your posts just a simple anwser will do not all the sarcasm ok.
Matt-max said:
"i pronounce it frank'-fort."
Bingo!
D-max Man
05-06-2002, 07:17
Testing showed valve seat temps to be over 100 degrees cooler on the aluminum heads vs. cast iron.
"Perhaps a more significant test is the thermal-shock cycle, one of the most severe test procedures in the industry. With the thermostat removed, the engine is run on a dyno at full load at full operating temperature. By switching a special valve in th eplumbing that supplies coolant to the engine, cold water can be fed directly into the cooling system. This is a brutal test for any engine, and if a head is going to warp and blow it's gasket, this test will make it happen.
Several engines were successfully tested on both cycles, and GM is confident that the Duramax is ready."
OCT 2000 Motorage
01_Duramax_Dually
05-06-2002, 08:08
OK OK...I am sorry all. I should have not let my "Wing Nut" head tightening secret out. Well It just got so tiring changing the heads all the time. Had to drop the exhaust, pull the intake....Geeeez. So I felt it was time to make the set up a bit more quick change. I have cotter pins that hold on my exhaust at the head now. I made them all slip fit. I am almost to the point now that if I melt a head down while towing somewhere, I can make road side repairs.... :D :D :D .My wife reads a book and I get out and get to work.
Torqueing the "Wing Nuts" is easy. I have a special cut set of Vise Grips to hold it. I also installed it with a side mounted small dial indicator for torque...I have found that the head functions very nicely with about 30-40 ft lbs Tq and this makes it easier to remove. I found this out through experimentation only because I have gone through 20 sets of heads to date. I am thinking about starting a foundry soon.
I wonder what everybody would be saying if the block was Aluminum and the heads were Cast Iron...LOL...Bawahahahahaha.
In all seriousness. I am not bagging on anyone here. I just think the question is silly. It is not like this concept has not been completely thought out and used. Fe blocks and AL heads have been used for years. Low compression, High Compression, alternative fuels...You name it.
I guess if the arguement is that there is unknowns when plunking down 40K for a truck, then I say go buy the other guys...bottomline, you live with their "Other" guys unknowns. So you have to ask yourself.."Am I really saving $3K"
OK MDRAG...This was not nastiness...just some good ol "Stand up for what you believe"
Cat320, I use my truck alot for hauling, Towing an 11k lb trailer...and I have the heaviest Model offered with a CC, long Bed, Dually, 4x4. My tows routinely include trips through the Mojave desert in temperatures well over 100 degrees up 6% grades that seem to go for miles.
[ 05-06-2002: Message edited by: 01_Duramax_Dually ]</p>
Allison Jettester
05-06-2002, 08:57
I'm surprised nobody (unless I missed it) has mentioned that the Corvette, Camaro and Pontiac have been running aluminum heads with a cast iron block for over 15 years. Some make well over 300 HP and there are not a lot of reported problems that I know of. I have a 90 'Vette with the L98 aluminum heads and cast block with over 120,000 miles on it, with no head problems. It sees 5000 rpm regularly (oops!,) the factory fans don't come on 'til around 225 degrees F. and the heads haven't even dripped on the exhaust manifold yet (I'm on my third heavy duty clutch though).
By the way, I'm also an engineer who thinks the Duramax Diesel is the most well engineered engine I've ever seen--and I've tested jet engines (Pratt & Whitney TF-30 engine in the F-14 Tomcat, Allison TF-41 in the A-7E Corsair II, Rolls Royce Pegasus in the AV-8B Harrier) for thirty years for the Navy and Marine Corps and worked on car and truck engines for over forty. I've spent my life fixing the design problems in the above mention jet engines, so I should know a good thing when I see, hear and drive it.
Joe
Diesels have higher cylinder pressures than gassers, don't they. I believe that's where the concern is.
I had a Ford Fairlane with a 289 in it. It was over-cammed and would bend/break pushrods, break valve springs and studs. Needless to say, I had an on board repair routine. All the parts in my Craftsman toolbox.... on the highway I hear the rattling and I know what to do. Pull over, pop the hood, remove those wing nut retained valve covers, let off cooling pressure if a rocker arm stud broke, remove and replace broken parts, get back on the road. It didn't have aluminum heads!
Now in my Dmax, I don't have any tools. Imagine that!
Cat320,
Ignore some of these idiots. These discussions tend to get carried way pretty quick. As for aluminum vs cast iron, I wouldn't worry about it! High power engines have been using aluminum heads for a LONG time. Take a close look at the next top fuel dragster you see. 7000hp in 500cid with cylinder pressures WAY higher than any DMax will EVER see.
The differences in thermal expansion is an issue. However, it usually isn't out the head cracking or warping, it is usually a problem with head gaskets failing if you over heat the engine. That can be fixed fairly easily with a new set of head gaskets. Thankfully, gasket technology has come a long way over the last 50 years or so and this isn't near as big a problem as it used to be.
For me, the short answer is that aluminum IS the future of automobile engines, cars and trucks. Why? EPA and CAFE. Weight kills and cast iron has a LOT of weight in a small valume. Aluminum is much, much lighter and is a great replacement in most applications. (Note: I would not EVER run aluminum rods or rocker arms on the street. They WILL break eventually due to the way aluminum fatigues. Steel is much better in this regard, of course, a head isn't cyclically stressed the same way that a rod or rocker arm is....). I think Isuzu (sp?) knows how to make diesel enginers that last. Besides, if there is a design flaw, it WILL be found out and GM will have no choice but to make it right (I guess that is ONE small advantage to the US legal system...) one way or another.
And if it REALLY bothers you, put a very good, very accurate temperature guage on your truck and keep your eye on it. When it gets to the high side (and you will have to pick your own "safe" number), pull over and let it cool down. Keep the collant toped up and the radiator clean and in good working order. And then drive the wheels off your truck!
Roamer,
Agree with all you said except....
Dragsters aren't designed to run for over 200,000-300,000 miles without being torn apart for a good ten years or longer. The effects of expansion and contraction for the probably 15-20,000 or more warm up cycles along with age degradation of seals and gaskets are not an issue with dragsters. The Dmax uses specially designed stainless steel laminated gasketson the heads and on the cast iron exhaust manifolds bolted to aluminum heads. I'm surprised no one has mentioned that one in all this.
I believe the Dmax is a design winner and is putting the alum head usage issue to bed though.
[ 05-06-2002: Message edited by: hoot ]</p>
Think I am going to mount a small basket under the engine to catch all that aluminum when it melts. Then I can pour it into the "head mold" that I have mounted in the truck bed. That way I do not have to carry spares around all the time you dummy's. Don't you know spares take up alot of room.
CAT320,
Pay attention to the above post for D-max Man. When I was researching both fxxd and Dmax trucks I too was quite concerned with the Aluminum head issue. I was just as concerned with the cativation issue with Fxxd. Somewhere I came across a readout of the full list of procedures the Dmax goes through when temps rise above normal. It is a greater number of events that occur to protect the engine than D-max Man has stated. I only wish I still had the information bookmarked on my computer. My work computer was updated and the browser changed while I was on vacation. Goodbye to my entire list of valuable work and play bookmarks.
Bottom line. I too was concerned due to what I had read on other websites. Once I read the full information on how the engine can protect itself I purchased my GMC. I have found this forum very valuable in my every need. Not once have I ever heard of a real person having an aluminum head problem. The only problems I have heard have were posted on other brands forums something to the effect of: My friend's brother-in-laws cousin had three heads meltdown. When taken to the dealer the dealer said it happens all the time and they would not own one. Forgot to mention that they never drove over 15mph.
The bottom line is that some sites serve up bilge and banter while some sites like this one tend to stick with facts. There is some fun on this site but very little bashing of members or other brands or sites. I have a high level of confidence in this site. It was a hard decision for me to choose the GMC over the Fxxd. In fact, I drive my GMC while wearing my Fxxd racing hat.
tonkater
05-06-2002, 14:04
Cat320 ,
I hope you'll make it a point to come to the Northeast CT diesel day and meet some of the guys with Dmax, 6.5 and 6.2 , and have your reservations about this engine resolved.
I for one am more concerned about all the computers on the truck than the heads.
I've also managed to get 500,000 miles on my 88 ext cab with 6.2 , and 250,000 on my 85 shortbed k 10 with 6.2.
Back in my drag racing days a bunch of buddies ran 396 and 454 s with alm heads. Don't remember any real rash of problems.
Info still to be announced on CT diesel day.
Cat320,
So did you get all you answer's, answered? ......... It appears to me to be a NON-ISSUE..........Will be waiting for your summary ......If
answer's were what you came for, and are posting for ........ I'm sure as you know, WE have been loaded up with sarcasm, untruth's, and rumors, from the start and had to be on the defense ....... For this reason we rally ......But we,D-MAX owners, IMHO can sit tall in our saddle's knowing now that the competition has to Race to catch up to GM'S engineering standard.........Because we are driving a winning combination ......... If you are offended as I've been told, on other sites ,Check your "FEELING'S" at the door ........ We are PRO GM Here, and proud of it...
MAC
[ 05-06-2002: Message edited by: mackin ]</p>
slapshot44
05-06-2002, 18:10
Gentlemen, I apologize to all. After re-reading my posts, I can see where I definitely could be accused of being sarcastic (although in my defense I was only countering digs made at my choice of profession and the complete lack of acknowledgement of my efforts to answer the original question with at least some actual scientific basis.) Besides, finals are coming up soon and I should be studying instead of spouting off scientific drivel that nobody really wants to hear... (please insert "humility" Graemlin here)
So, I will try to be civil. In my opinion, I'm thinking that we are being had by a Troll, albeit a very good one. After reviewing all of the suspect posts, I've come to some interesting conclusions;
An initial post expressing concern over a non-issue that has already been exposed as myth ad nauseum on this and other boards.
Failure to acknowledge any valid points made by many people trying to refute the concerns.
Reference to a source that proclaims that aluminum heads cannot handle the stresses put on them that turns out to not have any experience with aluminum heads.
Every post makes negative comments as to GM's lack of ability to make any good product, or the Duramax is too expensive (the list price on the F**d I looked at was actually $1000 more than the list price on my Duramax.), or is still too unproven to be trusted, or we just don't work our trucks hard enough, or if aluminum is so great why doesn't every engine have aluminum heads, well as I'm sure everyone can see by now, this is exactly the same kind of comments that we find on certain other boards...
Many people answered this question many times in many different ways in many different posts. I don't think the explanations could be any simpler than they've been. A simple, honest answer would be that there hasn't been any problems with our aluminum heads, period. (Now if I type the word period, do I still need to put the "." at the end?) But that isn't really an answer, its a statement.
So, if we don't have a Troll at work here... does anyone else besides me want to say; "What were you thinking, man?" If you really hate GM so much, why are you here? If you just can't be convinced that the Duramax/Allison is a valid drivetrain, then set your mind at ease and purchase one of the other brands. But please don't continue trying to reinforce myths and put doubts into other readers who are still trying to make up their minds.
I also want to apologize for the length of my posts. I don't mean for them to get so long, but at least I try to make them entertaining. BTW, I am proud that I will be an ingin-ear in a few more semesters (if anyone hires me.) But I'm still wondering when I'm going to get some classes on how to actually drive a train... (and why do we need all this math stuff to do that?) :rolleyes:
[ 05-06-2002: Message edited by: slapshot44 ]</p>
slapshot44 ,
AMEN, BROTHA.....AMEN
But I'm still wondering when I'm going to get some classes on how to actually drive a train... (and why do we need all this math stuff to do that?)
So you will be so sick of adding ...You will not count all those "clunks" over the railroad ties...And drive yourself mental.....LOL
MAC :D
[ 05-06-2002: Message edited by: mackin ]</p>
sonofagun
05-06-2002, 18:24
Roamer ---- Ignore some of these idiots. EXCUSE ME!!!
Slashot 44,
I said what you said in your last post. Guys gotta be laughin himself silly at this point. That or he is clueless and better of in a F***.
Bob
slapshot44
05-06-2002, 20:14
son of a gun,
Yeah, I saw your post again when I was reviewing. I guess I just take longer to catch on. I get the feeling you were doing a little laughing also... Hey, I updated my signature in your honor. Check it out. I am also thinking about asking Kennedy if I can license a certain line in his signature.
Denny
Has anyone seen the Caddy commercial where they lose thier coolant in the desert, in summer, and say it's ok...we can drive 50 miles with no coolant? I believe that that Northsar engine has aluminum heads. Most auto manufacturers have made engines over the last decade with aluminum heads.
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