injectors = broken crank ?

[dmaxvaz]

Hmmm good question. It seems serious but I think you have a catch somewhere :rofl:

Pat proved you can do 800hp on stock sticks. Now like you said they arent flowed (but Pat said Bosch test procedures when new are within 5%. )

Whrn I looked into Extrude Hone I think it was like $48 an injector and then shipping so like $400. I think my injectors done from Guy were a little under $1000. There have been several threads the last few months arguing back and forth about the issue - I decided to play it safe. Same reason I went with other random upgrades like ARP rocker tree studs - insurance that no stupid little item is going to cause some sort of large failure.

Im blessed with a job thats allowing me to make my truck payment still every month and next month have the motor all paid off.... so I wasnt as worried about it taking a bit longer and upgrading a few more parts. Now of course Ive slacked off like an idiot for about 3 of those months, but it sthould be coming together quickly now.

So to answer the question I cant say Im positive one way or the other. Im trying for more of a max effort engine build, so I decided to do them. It seems like you can go far with 2xcp3 and stocks though.

is this special pricing for $20k engine purchase, or is this for everyone? i thought i read somewhere that it was in the $1600 range, just to flow test them?

 

[slowlmm]

Hmmm good question. It seems serious but I think you have a catch somewhere :rofl:

Pat proved you can do 800hp on stock sticks. Now like you said they arent flowed (but Pat said Bosch test procedures when new are within 5%. )

Whrn I looked into Extrude Hone I think it was like $48 an injector and then shipping so like $400. I think my injectors done from Guy were a little under $1000. There have been several threads the last few months arguing back and forth about the issue - I decided to play it safe. Same reason I went with other random upgrades like ARP rocker tree studs - insurance that no stupid little item is going to cause some sort of large failure.

Im blessed with a job thats allowing me to make my truck payment still every month and next month have the motor all paid off.... so I wasnt as worried about it taking a bit longer and upgrading a few more parts. Now of course Ive slacked off like an idiot for about 3 of those months, but it sthould be coming together quickly now.

So to answer the question I cant say Im positive one way or the other. Im trying for more of a max effort engine build, so I decided to do them. It seems like you can go far with 2xcp3 and stocks though.

DId he drop his price or something and that was flow tested ? but you said you got no flow data sheet ? I would like to see how it looked before and after just curious to see how far off and how they corrected them after

 

[S Phinney]

Sorry guys, I'm so damn busy I don't have much time to hit the boards as much as I used to.

Here is my humble opinion.

For those that don’t know me, my research in engine harmonics goes back to 1994 when I did battle against Fluid Damper on failed cranks, rods and bearings in NASCAR engines.

You can destroy anything by inducing the right harmonic. This can occur if the engine is balanced for a different rpm than which it is operating in. This can also occur as a result of uneven firing pulses. Or perhaps a combination of both and exponentially more cylinder pressure than the crank was ever designed for.

Every engine has naturally occurring harmonics as result of just rotating the engine, now add firing pulses to the mix and the equation just became far more complicated. Induce just the right harmonic or combination of harmonics at the right time, under the right circumstances and bingo we have a broken crank. A “Perfect Storm” scenario.

“Balancing” a crankshaft by attaching weights to the crank to simulate the piston and rod assembly weight, and then spinning it on a machine that senses vibration is nothing more than an attempt to tune these harmonics to occur at an rpm other than where we are going to operate the engine. The crankshaft is never really balanced for all rpms, it is just better in some and worse in others. The key is to make sure the really severe harmonics occur at an rpm in which we won’t be operating. This just targets the rotating assembly and has nothing to do with the harmonics occurring as a result of the firing pulses.

With each firing pulse, energy is transferred through the piston and rod into the crank. Studies have shown that the rod throw on the crank actually deflects and twists, then springs back past it‘s normal orientation, in an ever decreasing fashion until the next firing pulse for that cylinder or the next cylinder attached to that same rod throw, and then the whole nightmare repeats itself. Look up “resonant frequencies” and/or “oscillations” etc. for more in depth explanations. These pulses also send harmonics through the crankshaft.

Greater cylinder pressures can generate greater amounts of twist for a given crankshaft. Increasing the twist past the crankshaft’s limit, results in crankshaft failure. Kind of like bending a piece of metal back and forth until it finally breaks or cracks.

What I find very interesting is the fact that most of the crank failures occur in the same spot. Usually, right behind the first rod throw intersecting the second main journal.

This would indicate an area of concentration for the above described harmonics, whether they are injector related or balance related or both.

We can’t always control these harmonics, as in an injector pulse varying over the life of the injector. The next best thing is to try and absorb and dissipate them, as in the use of a harmonic damper. Dampers can be tuned for specific rpms, power levels, etc using a variety of factors.

Bosch has a specific test procedure for the Dmax injectors. The injector is flow tested at various pressures and pulse widths that simulate real world parameters the injector will see during use. The injector must be within 5% of a target value at each data point in order to past the Bosch test. We typically control our modified injectors to less than 3%, and a very specific spray pattern. Some injectors work great at idle and go away in the mid range, some just the opposite. An uneven firing pulse at any of these levels could be just the thing that burns a piston or breaks a crank. I have tested other modified injectors that were 30% different within the set, the spray patterns were as uneven as the flow would indicate.

The customers never suspected their injectors were that far off from their seat of the pants feel, until the engine failed.

Spinning off the tips and having them extrude honed and reinstalling them without properly flow testing and calibrating is just one giant gamble no matter how you look at it. Some will win, some will lose. It is your engine, your decision. Some shops use air to flow test the tips. Some shops test the entire injector using some test they concocted to fit their test equipment that really isn’t designed for common rail injectors but was instead adapted over. Both result in tests that mean nothing. The injectors need to be tested under the same parameters and pulse widths they will experience in the field, anything less or different is just plain useless info.

Nothing is 100%. The “Perfect Storm” can occur at any time and routinely does in all forms of racing. At best all we can do is take the necessary steps in order to minimize the chance that it will occur.

Guy

Well said Guy. My crank broke in the same spot as most. There were no real signs of a existing condition that you could have prevented. The injectors had just been replaced in the previous months by GM. When I did my build I had them injectors flowed and balanced. I came to find that the injectors were really deficient from the OE Bosch standards. Some were as much as 67% short at WOT. The truck seemed to run fine except that it still got poor fuel economy. I believe that it was a combination of factors, that create those "bad harmonics" that will destroy any engine from stock to highly modified, that caused my crank to break. Even after the new build I have noticed my injectors go from near perfect to having balance rate issues. Some say that high egts distort the new near perfect nozzles and I'm sure that fuel contaminants are a major player in the modified injectors falling prey to self destruction. All said if you build it, it will break.

 

[BIG DIPPER]

Matt ...AND MATT ONLY,

I didn't start this thread. I know it looks that way, but I didn't. So, if you took it as me calling you a cheerleader or nutsucker or whatever you guys are calling it these days...it was not intended. I asked Jay to be open about his finding and your first comment and the only "resulting" comment that referenced his injectors....so I wanted more than your open ended comment. I know this isn't too much to ask. If you feel I have a problem with you because of it, again, it was not intended and at this moment, I still don't have a problem with you. I REPEATEDLY said I had no personal agenda or feeling in this...only wanted a clarification for people pointing fingers at the injectors when cranks break.

I could continue on with my thoughts or my perception, but why bother.....maybe on another site. I would like to discuss some of Guy's comments as I feel I have a good argument(discussion)....I just don't see the point. I know Jay on a more personal level than just a customer so I will know exactly what the results will be.....but I can guarantee I will never have him be open about anything he tells/questions me about, it simply isn't worth it. Sometimes it feels like every post someone makes they are running for office. I'm glad I'm not in bed with anyone that I feel I have to protect everytime I sit in front of the computer. Maybe in the human race, the skin gets thicker the farther east you come.....

 

[LBZ]

Matt what is your opinion on what the rest of us young'ins (with less than 20,000$ to spend) should do for injectors? Run stock (which arent flow tested) or run [not flow tested] aftermarket injectors?

Just curious...

ben

FYI Bosch flow tests ALL of their injectors. Stock and racing ones. S Phinney hit the nail on the head - contaminants in diesel are a HUGE factor in fuel system compenent wear and performance. Why do you think CR Diesels use 3 micron filters?

 

[paint94979]

is this special pricing for $20k engine purchase, or is this for everyone? i thought i read somewhere that it was in the $1600 range, just to flow test them?

DId he drop his price or something and that was flow tested ? but you said you got no flow data sheet ? I would like to see how it looked before and after just curious to see how far off and how they corrected them after

The price that Matt paid for his injectors are none your business.... and that is also irrelevant to the topic at hand.

 

[05lly2500hd]

WOW, what a read..........keep up the good tech guys. I thought the thread was started in a civil manner. Maybe there are some underlying issues I'm not aware of..........yet there are several underlying issues many of us are not aware of. There's a smoke screen up, and too many people can't see through it.
I don't know BIGDIPPER from anyone else, only know his name is George because of asking about these injectors, but I don't see where he attacked anyone. Seemed to me he was trying to defend himself, and some decided to push him off...........through the smoke screen......
Yeah, I'll prolly get bitched at for this, so be it. Or my post will be deleted, oh well. Maybe some of you can get the hint and consider, before so.

I'll shut up now...........back on topic.

 

[SteveFord]

800 hp on stock sticks with fuel only??? Bet you wouldn't have to worry about the crank breaking.

 

[SIKDMAX]

The price that Matt paid for his injectors are none your business.... and that is also irrelevant to the topic at hand.

Nah it doesnt matter, I didnt get any special pricing or any 'deals'.

I just checked my invoice and it says Modify, Flow Test and Calibrate Injectors 60% over. $1500.00

 

[dmaxvaz]

The price that Matt paid for his injectors are none your business.... and that is also irrelevant to the topic at hand.[/QUOTE]
paint94979, if this pricing was a secret, he wouldnt have posted it here
it is relevent info because this thread is about balanced/unbalanced injectors and broken cranks

 

[racinmike77]

So if it is to be a tech thread, the personal vendettas must stop.

Instead of condemning people from posting on a forum!!!! Why dont you post some tech about one of your six blow ups?

 

[slowlmm]

The price that Matt paid for his injectors are none your business.... and that is also irrelevant to the topic at hand.

yes it is relavent becuase the diffrence between 400 and 1000 isint to far off but 400 to 1500 is. its one reason why i did not do mine. stop trying to be everybody body gaurd. wicj goes over like a sack of wet noodles anyways


mat thanks for answering the price question. I would still like to see the diffrence from before and after. I,m thinking it could really show how fd up stock injectors are. mabey guy can post some sheets if you dont have any. I dont know how a bad injector could really f up a crank unless if caused a big vibration wich i could see as possible. but i deff could see it as a cracking or splitting issue of our pistons. especially if stock sticks are far off.

 

[Kat]

Instead of condemning people from posting on a forum!!!! Why dont you post some tech about one of your six blow ups?

You have a PM so I don't high jack this thread :hello:

 

[SBCNX20]

I spoke to Jay eariler this evening and he told me I should take a look at this thread........ Wish I had not.

I've got to say guys this thread is very upsetting to see, I thought we tried to keep ourselves to a higher standard than the other site that we almost "all" came from. Sad to see! Since I've been a member (06) this is as nasty and unproductive a thread that Duramaxdiesels has produced yet! Come on now, how about everyone swallows some pride and says a few sorry's and let's move on and fix this problem! That's is unless you guys wanna keep building engines every few weeks/months.:hug:

 

[SteveFord]

Well I have one idea why it gets like this just like it did on the other site.........
but this is about broken cranks and it started off with good tech.

 

[05lly2500hd]

I spoke to Jay eariler this evening and he told me I should take a look at this thread........ Wish I had not.

I've got to say guys this thread is very upsetting to see, I thought we tried to keep ourselves to a higher standard than the other site that we almost "all" came from. Sad to see! Since I've been a member (06) this is as nasty and unproductive a thread that Duramaxdiesels has produced yet! Come on now, how about everyone swallows some pride and says a few sorry's and let's move on and fix this problem! That's is unless you guys wanna keep building engines every few weeks/months.:hug:

I'm probably one of the ones instigating, BUT I DO AGREE with you. I enjoy this site, more than other sites including the dp and I've been a member there for 5+ years.
Unforunately, there are a few, a select slim few that lie and hide things from the masses, somehow for their own benefit, therefore with that being said and still being done, we'll never be able to fully advance/progress. I believe that's why you have all your little groups, salad, soup, steak, etc.
But the thing is and I can say I'm guilty myself is that too many people don't want to hear the arguing, it's just a headache. Truth be told....arguing/debate etc. is healthy it brings out the truth and actually helps as long as it stays civil.
As far as the personal attacks, etc. I have to disagree with them. Too many people get hung up and offended and attack others, etc.
I will shut up and hopefully we can all learn something from this engine failure and try to prevent it.
For the failed engine owner, I feel bad. Sorry for the luck. I've been there to an extent and it sucks...BAD. So hopefully we CAN learn from your misfortune, but not in vain.

on edit: just go back through every post on here and DP and notice who is in the mix of EVERY single shut down closed thread....................................................................................................................................................

 

[The Neens]

Instead of condemning people from posting on a forum!!!! Why dont you post some tech about one of your six blow ups?

I spoke to Jay eariler this evening and he told me I should take a look at this thread........ Wish I had not.

I've got to say guys this thread is very upsetting to see, I thought we tried to keep ourselves to a higher standard than the other site that we almost "all" came from. Sad to see! Since I've been a member (06) this is as nasty and unproductive a thread that Duramaxdiesels has produced yet! Come on now, how about everyone swallows some pride and says a few sorry's and let's move on and fix this problem! That's is unless you guys wanna keep building engines every few weeks/months.:hug:

Well I have one idea why it gets like this just like it did on the other site.........
but this is about broken cranks and it started off with good tech.

I'm probably one of the ones instigating, BUT I DO AGREE with you. I enjoy this site, more than other sites including the dp and I've been a member there for 5+ years.
Unforunately, there are a few, a select slim few that lie and hide things from the masses, somehow for their own benefit, therefore with that being said and still being done, we'll never be able to fully advance/progress. I believe that's why you have all your little groups, salad, soup, steak, etc.
But the thing is and I can say I'm guilty myself is that too many people don't want to hear the arguing, it's just a headache. Truth be told....arguing/debate etc. is healthy it brings out the truth and actually helps as long as it stays civil.
As far as the personal attacks, etc. I have to disagree with them. Too many people get hung up and offended and attack others, etc.
I will shut up and hopefully we can all learn something from this engine failure and try to prevent it.
For the failed engine owner, I feel bad. Sorry for the luck. I've been there to an extent and it sucks...BAD. So hopefully we CAN learn from your misfortune, but not in vain.

on edit: just go back through every post on here and DP and notice who is in the mix of EVERY single shut down closed thread....................................................................................................................................................

You all have said what you felt you needed to say...There are more, but it's not necessary to start on page 1...

Nothing more off topic, simple as that...

Thank you...

 

[McRat]

Instead of condemning people from posting on a forum!!!! Why dont you post some tech about one of your six blow ups?

Let's see. It's a thread about injector-related crank failures. No, not a thread about people. No, it's not about Guy Tripp, SikDmax?, Big Dipper, Mike L, or me. It's about parts.

None of my Dmax racing engine failures have been injector or crankshafts. Without doing a search, here's what I remember:

1) Factory oil pump gear falling off. No other damage.
2) Bent all 8 rods. No other damage.
3) Melted pistons. No other damage.
4) Seized 2 pistons in bores at 181mph. Engine block/heads/pistons totalled, crank and rods saved.
5) Blown headgasket, no other damage.
6) Waterpump failure at 5200+ rpm. Melting barely started.
7) Oil comes out dipstick and breathers, still runs. No autopsy yet.

All crankshafts have been reused, IIRC. The original engine the truck came with is still sitting here, stock bore. I've run OEM, 10% DDP, 29% MDE, and 100% SCD injectors. One cracked LLY injector, external leak. 2 melted injector nozzles from 181mph pass. No balance failures or stuck injectors.

So my opinion on crank failures and injector failures while racing is limited to information I've seen and have been told "behind the scenes". I do not post other people's engine failures when discussed in private.

I've discussed more about my engines, both good and bad, than most diesel racers, regardless of brand.

So exactly why are you slamming me for not discussing them?

Can a bad injector destroy an engine? Lordy, if you have to ask that, you need to stick to carburated stuff. Can it break it a crank? I don't think anyone knows for sure either way. I do know that balanced injectors are not a bigger risk to a crankshaft than unbalanced ones. No matter what the infomercials say.

I won't run unbalanced injectors. Period. When the first set of big nozzles were sent to me to run 5? years ago, I was told they were tested, but they still had extrude hone fluid on them, so I sent them back without running them. Since then, only OEM or tested injectors will go in my trucks.

 

[mick]

I dont want to throw a cat amongst the pigeons but maybe the front end of the crank may be too light - not heavy enough to absorb some stress. The rear of the crank doesnt seem to have a problem and its got a big hunk of weight (Torque Converter) hanging off of it. Maybe we need to have a weight ( like a Supercharger Drive Pulley) hanging off the front to give it a bit of weight for a steady and absorbsion (and being supported to a certain degree by the weight on the belt). The older engines (Listers and the like) had big flywheels that tended to help with the rotation once they got moving. I bent every rod before throwing one out the side, but Crank Journals and Bearings were all like new and I had a 25 lb Pulley hanging off the Ati Balancer making some (reasonable) power. Only what I think ...........

 

[LBZ]

So your talking front to rear balancing.?

Interesting angle.....:hmm::thumb: