Im Just Learning About The Lbz Piston Cracking Issue, Can Anyone Explain Why And How This Happens? I Suppose Its Not Common, I Know Catastrophic Engine Failure Would Be A Possibility. What Is The Best Fix For This Problem, Ive Heard Of Guys Running Lb7 Or Lly Pistons But I Cant Recall Which Ones. Can I Get Aftermarket Lbz Pistons That Will Handle What Ever Is Thrown At Them? Eventually I Will Do A Complete Build With A socal Diesel 7.1l Stroker Kit I Know Its An $11,000+ Kit But That Is Ok I Will Be Breathing Hard On The 1000hp Range.

I have heard this same thing recently. I was at a very well known nationally recognized diesel shop and the guy cautioned me against going over 450-500 horse on my truck because he supposedly had three rebuilds of LBZ duramaxes he was currently doing for pistons/rods. They are dodge fanboys though so who knows if it is true.

I've heard it happens allot due to running too much timing. Not sure what is too much, but mine is still running strong at over 500 rwhp. I've run the hot tunes for over 15,000 miles and I'm hitting 12.6's on a completely stock motor. I've seen some tunes put the timing at over 35-39 degree's before top dead. I'm still well under that.

I would say 450-500 is safe i have heard more problem with them melting the pistons down more than I have heard of them shattering, I run a 450 horse EFI LIVE tune in my LBZ all day and night and it doesn't break a sweat. As for the rods they start failing over the 600 horse mark but there are alot of guys out there with more than 600 on stock rods. I beleive the problem lies when power hits to hard to fast like NOS and then the motor runs lean and scortches a piston.

Im Just Learning About The Lbz Piston Cracking Issue, Can Anyone Explain Why And How This Happens?.


thats a million dollar question that has yet to be answered. People can speculate all they want (timing, EGTs, cylinder pressure???), but there is no definitive answer IMO. Alll of those factors mentioned defiently do play a big role in putting pistons at risk, but theres really no rhyme or reason to when the pistons actually crack. Some trucks crack at 450rwhp for no reason, others last at 600+ rwhp with no problems...

ben

Couldnt have said it better Ben .

Seen many cracked pistons around the forum and one of my own . Most guys are going with the LB7/LLY piston . Using stock or having lip cut off piston bowl and some going with high boost are cutting .040 off the top of piston to lower compression . If you look at dodge pistons they dont have a lip on them and tend not to crack . Doesnt mean cutting lip on dmax pistons will cure cracking them though . It's just whats being done . Socal will even do valve reliefs in pistons for bigger cam . Everybody talked about the LBZ being better till a bunch of motors started cracking pistons at what seemed to be less hp than guys were cracking the LB7/LLY pistons . If your going to go for the full tilt 1000hp job then the billet pistons are what you will probably use .

No oil passages and hollow area in top of pistons for cooling though . Why most use the stock piston for street / race .

I have heard this same thing recently. I was at a very well known nationally recognized diesel shop.


which shop was that?

Im Just Learning About The Lbz Piston Cracking Issue, Can Anyone Explain Why And How This Happens? I Suppose Its Not Common, I Know Catastrophic Engine Failure Would Be A Possibility. What Is The Best Fix For This Problem, Ive Heard Of Guys Running Lb7 Or Lly Pistons But I Cant Recall Which Ones. Can I Get Aftermarket Lbz Pistons That Will Handle What Ever Is Thrown At Them? Eventually I Will Do A Complete Build With A socal Diesel 7.1l Stroker Kit I Know Its An $11,000+ Kit But That Is Ok I Will Be Breathing Hard On The 1000hp Range.

I hope that never happens to me

Well mine is on it's way to being pushed over the edge I would assume then, when I go home on my next R and R she will be turned up pretty high

A friend at the dealer is replacing a bad piston on a 06 D Max box truck with 40,000 miles on it. No power added at all.

I thought that more than just LBZ pistons were cracking.... Its just more common for the LBZ

Heading home from KY right now with a cracked piston LBZ on the trailer

Heading home from KY right now with a cracked piston LBZ on the trailer

:ro)

Im Just Learning About The Lbz Piston Cracking Issue, Can Anyone Explain Why And How This Happens? I Suppose Its Not Common, I Know Catastrophic Engine Failure Would Be A Possibility. What Is The Best Fix For This Problem, Ive Heard Of Guys Running Lb7 Or Lly Pistons But I Cant Recall Which Ones. Can I Get Aftermarket Lbz Pistons That Will Handle What Ever Is Thrown At Them? Eventually I Will Do A Complete Build With A socal Diesel 7.1l Stroker Kit I Know Its An $11,000+ Kit But That Is Ok I Will Be Breathing Hard On The 1000hp Range.

IF you do the stroker kit from guy it comes with forged pistons tht is wht is used in the kit so u dont have to worry about useing lly or lb7 pistons :)

Mine cracked/hole blown through at idle. The tune was a 27* max timing tune that dynoed around 500 hp.

what are the symptoms of a cracked piston? thanks

Well said Ben, you're only safe until it happens to you. 500 RWHP+ trucks are most suceptable. I've seen it happen on tunes with all sorts of fuel and timing numbers. There are more variables than you want think about when you have your foot buried in it.

We can speculate, and be smart, but we don't know for sure. I have seen cylinder pressure data, seen the EGT numbers, and witnessed timing numbers your wife would slap you for. Still, some live and some don't.

Same rules apply in all forms of motor sports. Play long enough and you'll pay...

No B.S.,

Nick

what are the symptoms of a cracked piston? thanks

thump thummp thump thump sound blue or white smoke oil out the pcv or oil cap blow oil cap off oil in coolant tank any or all of the above are a few

whos truck eric? it looked like an lbz cracked one at shelbyville a couple weekends ago.

IF you do the stroker kit from guy it comes with forged pistons tht is wht is used in the kit so u dont have to worry about useing lly or lb7 pistons :)

You mean to tell me the factory pkstons are cast??? On this expensive of an engine where cylinder pressures are much higher in stock form than any gasoline engine they are putting cast pistons in? That is the most rediculous thing I've ever heard of.

I hope I dont experience this for a while.

Heading home from KY right now with a cracked piston LBZ on the trailer what part of ky where u in

check these out...

What caused this?

check these out...


is that your truck?

what part of ky where u in

Lawrenceburg, Louisville, Lexington, Winchester.

check these out...

Looks simualr to mine but mine was way worse on the side :eek:

What the hell is wrong with isuzu, why would you use worse pistons in an engine that is in its third generation? This makes no sense at all. Someone out there needs there ass kicked, sorry but its true.

What the hell is wrong with isuzu, why would you use worse pistons in an engine that is in its third generation? This makes no sense at all. Someone out there needs there ass kicked, sorry but its true.

its not isuzu's problem. the guys running more hp than stock are the ones that need their asses kicked. :rolleyes:

lbz's seem to be putting the holes in the pistons more so than anything. i have also heard of some doing it stock...

its not isuzu's problem. the guys running more hp than stock are the ones that need their asses kicked. :rolleyes:

I guess the guys that have cracked should have their asses kicked as well...?:rolleyes:

I guess the guys that have cracked should have their asses kicked as well...?:rolleyes:


if they crack them and accept the consequences then fine. If they run more power, crack them, and complain then thats dumb IMO.

ben

I agree ben.

I agree if you turn it up you should pay the price if something happens. BUT!!!! What if, like when I bought mine I knew that it would never be in for "ANY" warranty work as I bought it just to race/pull? Should I have got some money off because they figure in money for warranty work? Every new car/truck has a set amount in the price to cove such things. I want a rebait. P.S. mine is a LBZ run with high timing/NOS/CNG/but to he$$ from day one and was still going strong when I took it apart. I still think heat is the killer in the piston problem. Jeff

I've got boxes of LB7 and LLY pistons that look just the same. I do not think that the LBZ piston is any worse than the LB7 piston myself. It's all in how it's tuned and as Nick said he has seen things that have been done in tunes that are just plain and simple wrong. You cannot expect the piston or the engine for that matter to live when people do stupid things to them. We've run the LBZ piston to well over 1000 Hp and guess what it lives. Would I do it now days , no, as there are much better pistons now than there was before. The long and short is watch what you ask for as you might get it plus some things you didn't want.

if it lives then why bother doing something different?

Because I know when I'm pushing it and willing to accept the results that come along. Since we've got better parts it only made sense to update when the motor was pulled and checked after two years of racing. When racing, it's not uncommon just to replace pistons each and every season just for safety. My problem is when people start to blame the piston when there is nothing wrong with it and the 2 seasons of racing we did on them is plenty enough for me. The people who say it's fine to run stock pistons with some of the tuning that's out there these days are just asking for trouble. If you want 100,000 miles leave it stock or be prepared to live with what you get.

I guess the guys that have cracked should have their asses kicked as well...?:rolleyes:

I meant to say that the guys that have cracked their pistons while being stock should be punished as well...?

I've got boxes of LB7 and LLY pistons that look just the same. I do not think that the LBZ piston is any worse than the LB7 piston myself. It's all in how it's tuned and as Nick said he has seen things that have been done in tunes that are just plain and simple wrong. You cannot expect the piston or the engine for that matter to live when people do stupid things to them. We've run the LBZ piston to well over 1000 Hp and guess what it lives. Would I do it now days , no, as there are much better pistons now than there was before. The long and short is watch what you ask for as you might get it plus some things you didn't want.


what do you consider living one pull on the dyno or 50-100,000 miles at over 550rwhp please show me someone who has done tht with a lbz or lmm piston ? let alone at 1000 hp. LBz -lmm pistons look pretty but there crap the diffnce between lb7-lly pistons being made by mahle and our crappy ass lbz lmm pistons being made by dimsum woo company or some crap same company tht makes daewoo pistons. it came down to the bottom dollar and and china one on this one. And of course proper tuening will help something live longer.

Diesel Power here on the board raced his truck for two seasons of drag racing and sled pulling. Drove the truck daily and put about 25K on the motor we put together with those good old LBZ pistons. He event posted the pictures of the pistons when they were removed here. Buck ran his truck drag racing to 9 second passes with NOS and #2 for a season with good old LBZ pistons as well. So those are two of the quickest and fastest Production Duramax trucks on the planet and they both ran LBZ pistons.

Now we have changed both over to our forged units as they are a much better piece but do not go out and try and tell me it's the LBZ pistons fault as I know better!

What the hell is wrong with isuzu, why would you use worse pistons in an engine that is in its third generation? This makes no sense at all. Someone out there needs there ass kicked, sorry but its true.


I think it is the design of the piston not so much the material. The LBZ has this big ass lip around the outside of it's bowl, which I am assumeing was done to lower compression ration, and IMHO I beleive it just traps to much heat in there.

The problem with the LBZ/LMM piston seems to be consistency.
Some live some don't.
Overall they have a higher failure rate than the LB7/LLY design.

Okay...as in most cases when it comes to car enthusiasts, I am torn.

I can certainly pick up a first generation LLY for cheaper than a LBZ or LMM equip Duramax and I want to make pretty big power. Am I asking for trouble down the road?

How do you tell the 1st gen LLY from the 2nd gen LLY which was basically a detuned LBZ?

06 is the only year the LLY/LBZ are wins minus the tune. I have no problems with my LBZ 450HP to the wheels and now it is more a few more go fast goodies are on there and I pull some damn big loads. Either way if you after big power you will need to build up the tranny. I would try and get the 6 speed alli better fuel mileage and a bit tougher built.

The problem with the LBZ/LMM piston seems to be consistency.
Some live some don't.
Overall they have a higher failure rate than the LB7/LLY design.

The exact same thing can be said for LB7/LLY pistons. Look at who is failing them and what they are running and that will tell you a lot. In the early days with the LB7 and LLY not near as many trucks were running around with dual CP3's and big turbo's. So when you make an apples to apples comparison the failure rate is no higher with the LBZ. The question is how much power are you after? Above 500 RwHp and your on borrowed time with a stock piston and rod.

With all due respect Steve, thats only two examples.

I cannot agree with the fact that duel fuelers and such not being around contributed to less failures. I would say that more LB7's now have been pushed harder then are the newer LBZ's based on the fact that those trucks are getting cheaper now. The hardcore or able ones seem to have a seperate 'play' truck from the daily work truck.



I dont think tuning has everything to do with it either. Yes, it does/can play a part, but not the whole problem. I dont know what the whole problem is though. Many of the ones I have seen are on stock trucks. Stock, no nothing, no exhaust, nothing.

Many more are on popular major brand tuner trucks, with some of the most popular devices on the market.

I'm not in the tight loop with Mahle nor do I have all sorts of failure analysis equipment, but I've been examining all of the failures I can to see patterns. LBZ pistons are not something that I would comfortably use anymore. Even the LBZ trucks with cracked pistons that come in get LB7 slugs.

Great...more confusion. Just when you think that LBZ is the way to go over the LMM...more fuel to the fire to stick with the older LB7 or LLY motors...:eek:

So the LB7 have leaky injectors. Were the replacement injectors better than the stockers and once they are replaced you no longer have issues with them?

Should I be looking for a clean 04-05 LLY and keep and eye on engine temps. Seems like that is the only problem with that mill. It gets the better slugs and no injector issues.

With all due respect Steve, thats only two examples.

I cannot agree with the fact that duel fuelers and such not being around contributed to less failures. I would say that more LB7's now have been pushed harder then are the newer LBZ's based on the fact that those trucks are getting cheaper now. The hardcore or able ones seem to have a seperate 'play' truck from the daily work truck.



I dont think tuning has everything to do with it either. Yes, it does/can play a part, but not the whole problem. I dont know what the whole problem is though. Many of the ones I have seen are on stock trucks. Stock, no nothing, no exhaust, nothing.

Many more are on popular major brand tuner trucks, with some of the most popular devices on the market.

I'm not in the tight loop with Mahle nor do I have all sorts of failure analysis equipment, but I've been examining all of the failures I can to see patterns. LBZ pistons are not something that I would comfortably use anymore. Even the LBZ trucks with cracked pistons that come in get LB7 slugs.


very well stated eric:agreed:

This is all based off of people assumptions and opinions man, why the hell haven't you gone and baught yourself a truck yet? You can't sit on here and then spen all day analyzeing what everyone said. All the D-max generations are great motors, no question periiod they are all greqat just go get one and you will see. They all have strong points and weak points, don't get stuck on the details go to ebay and see the amount of miles on some of these trucks and you will not need to be worried at all. Go get a damn truck!!!!!!!!!!!!!!!!

This is all based off of people assumptions and opinions man, why the hell haven't you gone and baught yourself a truck yet? You can't sit on here and then spen all day analyzeing what everyone said. All the D-max generations are great motors, no question periiod they are all greqat just go get one and you will see. They all have strong points and weak points, don't get stuck on the details go to ebay and see the amount of miles on some of these trucks and you will not need to be worried at all. Go get a damn truck!!!!!!!!!!!!!!!!

Agreed. I have had an LLY, LMM and now the LBZ. All good motors and my LLY never overheated. If it starts getting hot. Drop a gear and slow down. I had the #7 and #2 injectors go out and had the wire harness problem on my LLY @ 46k mi. LMM had a bad FPRV @ 7K mi. No problems at all with the LBZ with 37k mi. Anyone you choose you will be happy with. Be selective and look them over thoroughly. Pull up the warranty work history and buy one. I would buy all stock if it were me or one with the lowest miles as most would here. Good luck.

With all due respect Steve, thats only two examples.

I cannot agree with the fact that duel fuelers and such not being around contributed to less failures. I would say that more LB7's now have been pushed harder then are the newer LBZ's based on the fact that those trucks are getting cheaper now. The hardcore or able ones seem to have a seperate 'play' truck from the daily work truck.



I dont think tuning has everything to do with it either. Yes, it does/can play a part, but not the whole problem. I dont know what the whole problem is though. Many of the ones I have seen are on stock trucks. Stock, no nothing, no exhaust, nothing.

Many more are on popular major brand tuner trucks, with some of the most popular devices on the market.

I'm not in the tight loop with Mahle nor do I have all sorts of failure analysis equipment, but I've been examining all of the failures I can to see patterns. LBZ pistons are not something that I would comfortably use anymore. Even the LBZ trucks with cracked pistons that come in get LB7 slugs.

Yes it is 2 examples that were pushed very hard, mostlikely harder than anything else around here and had no failures and had LBZ pistons. It just goes to show when its done properly it works. How many of the trucks with failed pistons were running around dead stock? Who knows but the simple fact that the have worked without failure and the LB7 have worked without failure only goes to show something else is going on. Now as far as what your using Eric it could have something to do with what you feel and nothing more. The cost of LB7 pistons for complete pistons, rings, pins and clips are $1500 and the same for LBZ's are closer to $2000 makes it cheaper and the fact that your not installing an out of the box piston changes things as well. GM sells about 50,000 trucks per month and about 13,000 of them are Duramax trucks. Does anyone really think that there is a bad piston failure rate here? We see a cross section of maybe 500 trucks around here on the forum in a year!

"This is all based off of people assumptions and opinions" is about as good as it gets. Total all the trucks from the forum over one year that fail a piston and it's not event .5% of what GM sells in a year. This is a none issue in stock form but when it does happen to you it's a pain.

My sources inside GM indicate LMM/LBZ piston failure is definitely higher than LB7/LLY.

Look for GM to switch Dmax piston mfgs for 2010. ;)

It is true that every production engine made has its weaknesses and its strong points, I just question why an engine manufacture would use a piston in an engine that is only reliable in stock form. The lbz jumped to 360hp in 06 but with this new design comes a weaker piston with a higher possibility for failure. Sure they say they work fine in stock form but not everyone has a stock engine, its obvious the diesel aftermarket is absolutly huge and its becoming common place for guys to modify in various forms. Yes I know there are you guys who have ran stock pistons to high horsepower levels with no incidents but it wont happen consistently and they will fail there is no doubt. I have yet to push my engine to much over stock but I do plan to push it to 550-600hp and in my opinion this should be a safe level, but now im starting to wonder if my engine will live at this level. Im a diesel mechanic for Cummins, I have yet to see a B series crack a piston, I put together a 05 dodge that is running industrial injection twin turbos, 150hp 10 hole injectors, head studs, a duramax dragonfire cp3 thats 100% over stock, plus many other mods this an 800+ hp engine. It sees 80 psi plus boost and tows 20,000 lbs. Just goes to show what a good piston will handle and what the junk thats put in the lbz will handle.
You all can continue to make excuses for the lbz pistons and tell me how great they are stock but the truth is they are failure prone and they are not what should have been used in this engine. Im sure there are those who disagree but remember everyone has there own opinion and I love my GMC lbz duramax but I just wish the duramax was built as robust as a B series.

Kinda makes ya feel like your driving a bomb with a lit fuse............even stock....:(

Yes it is 2 examples that were pushed very hard, mostlikely harder than anything else around here and had no failures and had LBZ pistons. It just goes to show when its done properly it works. How many of the trucks with failed pistons were running around dead stock? Who knows but the simple fact that the have worked without failure and the LB7 have worked without failure only goes to show something else is going on. Now as far as what your using Eric it could have something to do with what you feel and nothing more. The cost of LB7 pistons for complete pistons, rings, pins and clips are $1500 and the same for LBZ's are closer to $2000 makes it cheaper and the fact that your not installing an out of the box piston changes things as well. GM sells about 50,000 trucks per month and about 13,000 of them are Duramax trucks. Does anyone really think that there is a bad piston failure rate here? We see a cross section of maybe 500 trucks around here on the forum in a year!

"This is all based off of people assumptions and opinions" is about as good as it gets. Total all the trucks from the forum over one year that fail a piston and it's not event .5% of what GM sells in a year. This is a none issue in stock form but when it does happen to you it's a pain.


Until you have worked on the amount of trucks Eric has, I suggest you refrain from using your select few examples. You don't deal with anything but the performance side, while Eric deals with both performance and normal service work. Also, because he does the service side of it, it allows him to gather more consistent info in a wider range than you in your performance only area. He has seen more things in these motors than you ever will. Deal with with them on a scale that he does and then your opinion will be weighed. My two cents. It's my opinion and I have the right to share it.

I know it is sacrilegious on this forum to even mention the idea of a Dodge, but how do their trucks compare to the Duramax equip GMs...?

A Dodge mechanic driving a Chevy does speak volumes.

55,000 hard driven, tire smokin, sled pulling, drag racing, ditch jumping miles on my truck.:D No bad pistons yet.:)

Until you have worked on the amount of trucks Eric has, I suggest you refrain from using your select few examples. You don't deal with anything but the performance side, while Eric deals with both performance and normal service work. Also, because he does the service side of it, it allows him to gather more consistent info in a wider range than you in your performance only area. He has seen more things in these motors than you ever will. Deal with with them on a scale that he does and then your opinion will be weighed. My two cents. It's my opinion and I have the right to share it.

Jerry Jerry

what is that supposed to mean?

Kinda makes ya feel like your driving a bomb with a lit fuse............even stock....:(


I'm getting a little nervous about my pistons now... I've been running my mid 12 second tune for a couple months now. Truck runs damn strong, but all these stories scare me, lol.

Stroke, did you take your meds today? LOL

Stroke, did you take your meds today? LOL

LMFWAO...

Stroke, did you take your meds today? LOL


no, i couldn't find them:think:. the stuff that goes through my mind, i tell ya. just had to vent a little...

blah blah blah everyones truck "runs great with no problems" right up until the big bang. You think you're invincible and you "got a good one" and its just everyone else that has bad luck. You're all wrong. Sorry.

ben

blah blah blah everyones truck "runs great with no problems" right up until the big bang. You think you're invincible and you "got a good one" and its just everyone else that has bad luck. You're all wrong. Sorry.

ben


But if sumthing happens 2 my truck, i dont care. Just a reason 2 upgrade it.:D Nothing is built perfectly.

There is no doubt that Cummins built a very strong engine and yes it takes a lot more power added prior to a failure. Should this be the way all manufactures do it............ we would all like it but the truth is it doesn't happen much anymore. Everyone has the right to believe what they want to believe about how it should have been done or how it could of been done but when it boils down to it we do not have a choice in how the manufacture builds it to start with. What we can control is how we rebuild it when it fails. I for one will use the best parts I can get for the intended application. Telling the customer that a LB7/LLY piston is stronger than a LBZ/LMM piston and is the way to go in a high Hp application is just wishful thinking.

what is that supposed to mean?

It is supposed to indicate that your response looked to be a tad on the aggressive side. That seems to be echoed by the comments made by people that know you after the fact as well.

My two cents. It's my opinion and I have the right to share it.

yeah, well i used to work for eric and share many of his beliefs with the things we have seen. plus, eric's response about meds is an inside joke that you wouldn't understand. i think what he said about me and the meds is hilarious!

:coolnana::coolnana:

...right up until the big bang....You're all wrong. Sorry.

ben

:eek:

My sources inside GM indicate LMM/LBZ piston failure is definitely higher than LB7/LLY

And lets not forget that the many thousands of LB7's produced was tuned at about 20% less HP than the LBZ/LMM.

I'm willing to bet that the biggest problem with piston failure is misuse of horsepower. Running a new generation diesel in the corner for extended periods of time while loaded is one example... Cracking of cast metals are usually caused by rapid temp changes in either direction.

wonder what the horsepower headroom will be on the new 2010 dmax..

Well for 2010 we are supposed to see 2 new engines. The 4.5L and the 6.9L so its going to be new parts for everything if it all stays on schedule. With the economy the way it is you never know anymore. There is also a rumor floating around the Bosch ECM will be gone on the 6.9L as well. New engine with new parts means lots of new things that might or might not happen!

the new big dmax is going to be a torque monster...i have heard 750 ftlbs as a min...

blah blah blah everyones truck "runs great with no problems" right up until the big bang. You think you're invincible and you "got a good one" and its just everyone else that has bad luck. You're all wrong. Sorry.

ben

X2 I just wish the bang was louder LOL not just a litttle pfff and thump thump thump.

There is no doubt that Cummins built a very strong engine and yes it takes a lot more power added prior to a failure. Should this be the way all manufactures do it............ we would all like it but the truth is it doesn't happen much anymore. Everyone has the right to believe what they want to believe about how it should have been done or how it could of been done but when it boils down to it we do not have a choice in how the manufacture builds it to start with. What we can control is how we rebuild it when it fails. I for one will use the best parts I can get for the intended application. Telling the customer that a LB7/LLY piston is stronger than a LBZ/LMM piston and is the way to go in a high Hp application is just wishful thinking.

And let me guess you sell produce envented pionered all the best parts out there and there only availble through tts as well right :rolleyes: Have you even tuned a Lmm yet ?

Well for 2010 we are supposed to see 2 new engines. The 4.5L and the 6.9L so its going to be new parts for everything if it all stays on schedule. With the economy the way it is you never know anymore. There is also a rumor floating around the Bosch ECM will be gone on the 6.9L as well. New engine with new parts means lots of new things that might or might not happen!

Steve how do you know its going to be 6.9? Im pretty sure its staying 6.6.

I dont see why they would ditch the bosch ECM. The injection system will probably stay bosch, just like it is on the 4.5. What other options are there for ecm's? Denso, bosch, delphi, siemens I dont see what else they would use.....why channge from the LMM

Heck. Steve probally designed it for em. Told them the didnt do things right so he would fix it. Then told Bosch their ECM is junk and designed his own.................................

I personally don't give a shit I'm gonna keep runnin the hell out my old girl, if it breaks it breaks I will just have an excuse to build it up big, Stroker LBZ?

Well.....i heard of the 6.9 also. Recently i dont believe anything until i see it. Not saying that its wrong or right, but time will tell. Everyone has there own opinion, which is why arguments arise. I might sound like a little bitch right now, but there are a lot of people out there that have the knowledge about a lot of things, but there is also the group that thinks they know a lot about crap, but dont....kinda like me. Im still learning a lot, everyday and tell people what i know or have expeirenced. Yea the cummins is a great and reliable motor and the dmax has accomplished a lot already, but everything has their ups and downs. Im at about 550 for HP and 1000ft lbs of torque for the last year and a half and have abused that power and no failures yet. Eventually i will have a bad problem, but that happens when added power is used and abused. All my opinion of course, but all im trying 2 say it that everything has their problems and need some time to be perfected a little bit and good things come and go. I dont know...may be just wasting my time typing this.

Steve how do you know its going to be 6.9? Im pretty sure its staying 6.6.

I dont see why they would ditch the bosch ECM. The injection system will probably stay bosch, just like it is on the 4.5. What other options are there for ecm's? Denso, bosch, delphi, siemens I dont see what else they would use.....why channge from the LMM


There's some internet ramblings about a 6.9L "Ultimax Diesel" and the 4.5L will be the Duramax. The 6.9 is rumored to be 425HP/750ft-lb with a beefed up 8 speed Allison...Iguess to give back some efficieny. I don't see the point at all myself, but if the interiors are as nice, if not nicer, I may go for one.

Back to the orginal thread I talked to guy tripp at socal diesel and he suggested that I not go over 28 degrees timing on stock pistons now he told me that yes I can give it more timing than 28 and he said will it make more power yes but will the pistons crack at timing higher than 28 degrees who knows he said so hopefully this helps some

Back to the orginal thread I talked to guy tripp at socal diesel and he suggested that I not go over 28 degrees timing on stock pistons now he told me that yes I can give it more timing than 28 and he said will it make more power yes but will the pistons crack at timing higher than 28 degrees who knows he said so hopefully this helps some
28 is considered safe. I ran a tune with 36* of timing at 3400rpm. never again...

Anyone know what the PPE Hot+2 E.T. is running for timing???

Anyone know what the PPE Hot+2 E.T. is running for timing???
What setting? i can ckeck for you.

ppe350 highest is 31* @3200rpm @120mm3.

32 max

32 max
If he hits 4800rpm :D

Ok thanks. Im runnin the 425hp tune.

What if i hit 4800??:D Like when im spinnin tires?

Ok thanks. Im runnin the 425hp tune.
Wheres your second cp3? :lol:

What if i hit 4800??:D Like when im spinnin tires?
just before you crack a piston. :D

No one has given me another cp3 yet):h....guess i just have 2 wait a little longer.:confuzeld

Alot of you fellers sure must make more money than I do. All this " I don't care if it breaks, run more power until it does" "ill run it until it blows up then build a new engine" All this on a 2-3 year old 45-50K truck? To blow a engine up just so you can build a new 10-15K motor? I like to have fun like everyone else but thats just nuts.

Alot of you fellers sure must make more money than I do. All this " I don't care if it breaks, run more power until it does" "ill run it until it blows up then build a new engine" All this on a 2-3 year old 45-50K truck? To blow a engine up just so you can build a new 10-15K motor? I like to have fun like everyone else but thats just nuts.

True, but my truck is my major hobby and i plan on building the motor eventually. So if it blows, then i just build it a little sooner then planned.:)

If my old girl pops at least I had fun doin it,

If my old girl pops at least I had fun doin it,
Im presently in the process of clearing up the carnage of a (little pop)! im learning the hard way that to go fast or to pull harder(without carnage)you MUST paybig $$$$$$$$to the man!Stock vehicles willnot take the abuse!!Also remember that "LACK OF POWER IS A DELIMIA!"

As you guys have seen with my posts, (Blown Engine!!!) my truck was a stock except for a cold air intake and an exhaust system. Blew the motor at 70,800 miles. Crack and a hole in the number 1 piston and General Motors wants to blame it on a power-adder. There weren't any!
I do agree that it is hit and miss with motors. I got the hit!:mad:

As you guys have seen with my posts, (Blown Engine!!!) my truck was a stock except for a cold air intake and an exhaust system. Blew the motor at 70,800 miles. Crack and a hole in the number 1 piston and General Motors wants to blame it on a power-adder. There weren't any!
I do agree that it is hit and miss with motors. I got the hit!:mad:

Sorry to get off topic, but did GM every get that figured out? Its BS to have them deny a claim due to a power adder when there wasn't one.

That's why I didn't worry about my 5yr/100k warranty. Even if I kept it stock, they would still deny the claim so let's have some fun. Also, FWIW, I wouldn't put it back to stock to try and get a warranty claim either. That's fraud in my book...

Rob

That's why I didn't worry about my 5yr/100k warranty. Even if I kept it stock, they would still deny the claim so let's have some fun. Also, FWIW, I wouldn't put it back to stock to try and get a warranty claim either. That's fraud in my book...

Rob

I just go to a very understanding dealer that over looks all the stuff on my truck for warranty work. I wouldn't claim anything that broke due to what i have done, and the Service manager even said he can't help me when I twist drive shafts or blow the thing up.

I have a pretty understanding dealer though too... He has stood behind a truck or two that uh didn't excactly meet the criteria for the warranty. But I will understand if they say no to my LBZ, gotta a bit much goin on for them to stand behind it.

Sorry to get off topic, but did GM every get that figured out? Its BS to have them deny a claim due to a power adder when there wasn't one.

No, they haven't yet! :mad: We are currently in the courts. Have to go through the system.

Yippee....and here I just bought a 2006. :eek:

i have never seen the innerds of a duramax but is the hole in the piston opposite from the injector tip? a few months ago we had a rep from cummins warning us not to fill the fuel filters on the new ISL hi pressure common rail bus engines because the smallest particles could cause an injector to stick open, turning it into a blowtorch. he said they must be filled by cycling the key about 20 times, using the lift pump to prime them. maybe someone was careless when changing a fuel filter and some debris fell in there? the d-max filter isn't exactly "easily accessible". this could help explain the failure of the stock-power engines anyway

Never thought about that haywire

i have never seen the innerds of a duramax but is the hole in the piston opposite from the injector tip?

the injector tip is centered in the cylinder.

Yippee....and here I just bought a 2006. :eek:
in 06 there is the lly and lbz you might have gotten lucky. Overheater or piston cracker :lol:

in 06 there is the lly and lbz you might have gotten lucky. Overheater or piston cracker :lol:

an 06 LLY is the same engine as the LBZ just detuned, so it would be a piston cracker too :(

LBZ anyway.

Well at least you didnt get an injector user.

I haven't been up here in months but it is nice to see the same people arguing over the same thing. I'll stick with my original thought on the subject. Since some live in HP/TQ situations and others don't it goes back to quality control on the inital processing of the piston, some pieces are just made better then others whether it be the alloy mix, impurity in the casting or mold..... you get my point. I'm at 400 to the wheels and it has 40,000 only towing, last blackstone report came back showing less then normal wear. If it blows f$%k it, it is not worth worrying about I'll cross that bridge when the time comes.

I haven't been up here in months but it is nice to see the same people arguing over the same thing. I'll stick with my original thought on the subject. Since some live in HP/TQ situations and others don't it goes back to quality control on the inital processing of the piston, some pieces are just made better then others whether it be the alloy mix, impurity in the casting or mold..... you get my point. I'm at 400 to the wheels and it has 40,000 only towing, last blackstone report came back showing less then normal wear. If it blows f$%k it, it is not worth worrying about I'll cross that bridge when the time comes.

x2 exactly what we've been thinkin too as far as materials and labor when it was manufactured. I've been running at over 531 rwhp for almost 20,000 miles now and I'll fix it if and when it breaks.

Anyone running the socal diesel 7.1L stroker kit? Soon as I save the cash thats what I think im going to get. Is there any machine work that has to be done? I dont really race, pull or tow much at this time but I plan to do a little of all of it in the future. I want to be able to run her as hard as I want and have no fear of it coming apart.

Anyone running the socal diesel 7.1L stroker kit? Soon as I save the cash thats what I think im going to get. Is there any machine work that has to be done? I dont really race, pull or tow much at this time but I plan to do a little of all of it in the future. I want to be able to run her as hard as I want and have no fear of it coming apart.


there are a few out there...

from what i have heard they are having trouble getting enough air in there ! Hopefully you save up somewhere in the 20 - 25k area because there will be more needed then just that kit.... add on a turbo or two, dual fueler, lift pump , trans, head work, a cam, more engine parts/work.....

Anyone running the socal diesel 7.1L stroker kit? Soon as I save the cash thats what I think im going to get. Is there any machine work that has to be done? I dont really race, pull or tow much at this time but I plan to do a little of all of it in the future. I want to be able to run her as hard as I want and have no fear of it coming apart.
why waste 20k when your goin to do all of them "a little bit"?
build the 6.6.

id say internals good up to 500 whp on duramaxes, any past that the piston issue or robs may be sufferingg

IMO 550-570rwhp for an LB7/LLY, and 600-610 for an LBZ/LMM,


Torque and tuning has a big role in this too. You can help the engine live longer if you tune it for 650rwhp, but only 1000-1100 ft lbs of torque

i have never seen the innerds of a duramax but is the hole in the piston opposite from the injector tip? a few months ago we had a rep from cummins warning us not to fill the fuel filters on the new ISL hi pressure common rail bus engines because the smallest particles could cause an injector to stick open, turning it into a blowtorch. he said they must be filled by cycling the key about 20 times, using the lift pump to prime them. maybe someone was careless when changing a fuel filter and some debris fell in there? the d-max filter isn't exactly "easily accessible". this could help explain the failure of the stock-power engines anyway

Good point, some ignorant old school Diesel techs still dump fuel into the filter before installing...VERY BAD IDEA !!
Always install the filter dry and use the Primer or Lift pump to fil the filter with CLEAN&FILTERED fuel.... any tiny piece of debris entering the injection system can cause catastrophic results to the Engine!:eek:

Wow, this is an old thread...

95,000 miles now and still no problems, even added a bigger hair drier a while back :D