Cat_rebel
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Not my truck, a buddy's 5.9L CR. I just took the picture.
EGT damage
- Thread starter littleredstroker
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Not my truck, a buddy's 5.9L CR. I just took the picture.
Project20v
New member
My 7.3 at 150k had all the pistons cracked and #6 cracked almost completely in half and burned a hole through it.
DP tuner SRP1 GTP38R stock injectors RR fuel system . I towed at 1250 a lot. I would let it get to 1300 and back out of it. This is running the DP 40 or 60 tow setting.
Towing 9-15k a couple times a month. Just running around empty I might have let it get to 1350 for a couple seconds. The lip on the bowl is the problem. the engine was stock until 110K, I bought it at 70k all stock.
You can see the pictures here:
http://powerstrokenation.com/forums/showthread.php?t=132705&highlight=
DP tuner SRP1 GTP38R stock injectors RR fuel system . I towed at 1250 a lot. I would let it get to 1300 and back out of it. This is running the DP 40 or 60 tow setting.
Towing 9-15k a couple times a month. Just running around empty I might have let it get to 1350 for a couple seconds. The lip on the bowl is the problem. the engine was stock until 110K, I bought it at 70k all stock.
You can see the pictures here:
http://powerstrokenation.com/forums/showthread.php?t=132705&highlight=
..there are other reasons that can cause pistons to crack & fracture...
excessive injection timing will cause very peaky cylinder pressure spikes...not excessive pressure...just pressure that ramped up far too quickly..imagine the difference between a slow moving hydraulic press
http://www.youtube.com/watch?v=oqlfiM2aNUo
...versus a high speed press...and how an aluminum piston would respond...
http://www.youtube.com/watch?v=Aeai6FZzNNo
the high speed one may bring back memories for some, LOL
and 'back in the day' I actually fractured the outside edge on some pistons down to the top piston ring...and temperature wasn't the culprit
tarm-
15-1600 degrees for 20 minutes would cause damage...
in my opinion~
A) inaccurate gauge
B) exaggerated temp/time
C) lucky
IF a truck was making THAT kind of temperature...for that long....can you imagine the speed that it must have been going????
I can't see it.
LOL ...can geography even allow that???
I've never seen a hill that could take that long to crest...and if it took you twenty or thirty minutes to go up that "hill"...even WITH a big ass load on a trailer...the driver was either going 200mph all the way up the hill..or 10mph in 4th gear...just don't see how that is even possible.
excessive injection timing will cause very peaky cylinder pressure spikes...not excessive pressure...just pressure that ramped up far too quickly..imagine the difference between a slow moving hydraulic press
http://www.youtube.com/watch?v=oqlfiM2aNUo
...versus a high speed press...and how an aluminum piston would respond...
http://www.youtube.com/watch?v=Aeai6FZzNNo
the high speed one may bring back memories for some, LOL
and 'back in the day' I actually fractured the outside edge on some pistons down to the top piston ring...and temperature wasn't the culprit
tarm-
15-1600 degrees for 20 minutes would cause damage...
in my opinion~
A) inaccurate gauge
B) exaggerated temp/time
C) lucky
IF a truck was making THAT kind of temperature...for that long....can you imagine the speed that it must have been going????
I can't see it.
LOL ...can geography even allow that???
I've never seen a hill that could take that long to crest...and if it took you twenty or thirty minutes to go up that "hill"...even WITH a big ass load on a trailer...the driver was either going 200mph all the way up the hill..or 10mph in 4th gear...just don't see how that is even possible.
Hotrodtractor
Moderator
Dave - that is an awesome analogy to compare engine tuning to industrial presses - some a decent force applied over a long period of time (slow) and some are a lot of force imparted in a very short period of time (fast). A good piece of industrial equipment that really shows this is the drop hammer - in that device the operator can adjust the stroke, speed, and force just by adjusting a simple flow control valve with his foot and timing it with the stroke of the machine just right. The best video that I could find of the is the one down below - note that with this one machine the operator is providing both nice smooth force impacts as well as harsh hard fast impacts just by changing the "tuning" of it.
There are probably better videos - but this is the one I found first.
| YouTube Video |
There are probably better videos - but this is the one I found first.
fordfreak4life
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Project20v
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If it is that simple why aren't all the guys running the DP cracking pistons?
In my case I think it was endurance heating of the bowl lip and advancing the timing under any circumstance only adds to it. Even with stock timing the lip cracks. In some conditions I would tow at 1250 for a couple hours at a time which I thought was ok. I still think that it is ok, just not with a deep re-entrant bowl design like the 7.3 has.
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fordfreak4life
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Dave,
Thank you. I normally thought of the effects of the pressure curve on the rod not the piston itself other than at the pin but now I guess it all comes together.
After Ross posted up the engine dyno sessions you guys ran on his engine I spent a good deal of time talking with him about what he saw. The one thing I was interested in was the changes in the CP curve as well as the actual peak about and its effect on torque levels. The ways by adjusting tuning how you could keep the same basic TQ level yet either lower CP or effect the actual curve to make it "softer". This was something I was very interested about as I think it points to why some engines live no issues at HP tq levels other engines get torn apart at.
This reason is why I felt to really get the best from tuning you needed at the very least CP testing equip and access to sometype of load dyno. Obviously both engine and wheel dyno would be ideal but engine would be the better of the two to remove the other variables.
Your analogy using the hydraulic presses above was great. It gives very clear explanations IMO. Thanks for taking the time to post this up.
Jason and you taking the time to give some of your insight has taken what would be your typical average thread into a very useful one.
Thank you. I normally thought of the effects of the pressure curve on the rod not the piston itself other than at the pin but now I guess it all comes together.
After Ross posted up the engine dyno sessions you guys ran on his engine I spent a good deal of time talking with him about what he saw. The one thing I was interested in was the changes in the CP curve as well as the actual peak about and its effect on torque levels. The ways by adjusting tuning how you could keep the same basic TQ level yet either lower CP or effect the actual curve to make it "softer". This was something I was very interested about as I think it points to why some engines live no issues at HP tq levels other engines get torn apart at.
This reason is why I felt to really get the best from tuning you needed at the very least CP testing equip and access to sometype of load dyno. Obviously both engine and wheel dyno would be ideal but engine would be the better of the two to remove the other variables.
Your analogy using the hydraulic presses above was great. It gives very clear explanations IMO. Thanks for taking the time to post this up.
Jason and you taking the time to give some of your insight has taken what would be your typical average thread into a very useful one.
Jason
New member
I guess what I want to know is...where all these guys got their 7.3's at that have them catastrophically failing?! So many posts by guys that say "oh it was the biggest pos that ive ever owned...150k miles and i was on my fourth motor, couldnt keep a tranny behind it, constantly putting rods through blocks, etc." ??? I mean *** me to tears...this board seems to have many anti 7.3 people, for being a Powerstroke forum....
OSCS
New member
What are you reading?
Strokersace
Well-known member
Very well typed.
OSCS
New member
exactly what i thought..
Dmstrucks02
New member
He possibly meant outside this one thread
This is what I was referencing Tarm. If im "that one guy" you are referring to.
Seems like the 7.3 is being compared to other motors. There have been lots of damaged motor threads lately but im not sure that has anything to do with the 7.3s reliability.
Tycorr,
Actually I was not refering to what you posted but what you qutoted by Jason. His post does not fit this thread at all. Its as if we were all discussing injector nozzle sizes and someone decided to post on how stupid everyone is for not liking the stock stereo system. Just is a bit out of place ya know. LOL
Actually I was not refering to what you posted but what you qutoted by Jason. His post does not fit this thread at all. Its as if we were all discussing injector nozzle sizes and someone decided to post on how stupid everyone is for not liking the stock stereo system. Just is a bit out of place ya know. LOL
Jason
New member
My comment was brought up after reading so many people talk about how their 7,3 didnt last any time at all, soon as they modded it, such and such happened..threw a rod, etc. Their was a poster in here who stated like 30 k miles after tuning his truck had done all sorts of damage. Then theres been a few threads about guys stating how it is the most unreliable piece of sht to ever grace a pickup, bc they had problems with it. Or Mink keeps popping of about the pmr motors. (not knocking Josh at all..if mine went id be pissed too.) But so many people talking about this broke, or that blew up, or within 15k miles of putting a chip on it i had a cracked piston. Maybe all these cases of destruction should be linked back to the owner, and not anything to do with the motor? Wayyyy too many 7.3's running around still that have never had a problem. I guess my comment doesnt follow the course of this thread exactly, but it just seems everytime you have a thread like this started you get three types of people who reply. The "never ever ever consider going over 1250 for even one second, hiroshima type explosions will follow"..the "peg that ***er my needle never goes UNDER 1250 and i have no problems", and the "yeah well i uses to pull loaded freight train cars down the highway, and routinely saw 1600 degrees did it for 3 years til thid pos motor popped on me, ill never put another _______ motor in this thing again".
Cat_rebel
New member
I'll back you up on this Jason, I see the same things posted all the time as well. Get's old when all you see is...."Oh the 7.3L is a POS & you can't trust em not to throw a rod over stock form."
Guess there must be more than a few freak trucks out there that run with a decent sized injector/turbo/tuned & tow heavy without issues. But those must be like the "fast Powerstrokes"........Aliens................:lookaround:
I can agree with that as well. I see guys in one thread talking about how they only push things every now and then and then in another thread boasting about how they wot everychance they get.
Others yet talking about how they romp on it whenever they leave the house on the road they live on. Can you say cold motor!?! Oil temps likely around 120f.
Sorry but I know how most 16-23 yr are on vehicles and you mix more than doubling hp in a 8-9k lb vehicle. Stuff is gonna break. It should be no surprise.
You look at other guys run many tunes but some how keep 500hp trucks alive with stock trans no head studs. They know to not hit it hard till the converter locks let of a bit at the shifts, always taking it easy until oil temps are up to full temp etc..
Then there are the giluys that when something about the engine is not running right their answer is todrive the piss out of it to se if that helps!?! I guess they think they will clean it out. Or they just keep driving it hard like kormal regardless of the pinging sound and extra smoke out the tailpipe.
My engine starts acting funny it gets limped home and parked till fixed. At the very least babied if its driven.
There is no doubt the 7.3 is not the strongest diesel out there but I agree I can see a number of these kabooms being driver/owner related.
Others yet talking about how they romp on it whenever they leave the house on the road they live on. Can you say cold motor!?! Oil temps likely around 120f.
Sorry but I know how most 16-23 yr are on vehicles and you mix more than doubling hp in a 8-9k lb vehicle. Stuff is gonna break. It should be no surprise.
You look at other guys run many tunes but some how keep 500hp trucks alive with stock trans no head studs. They know to not hit it hard till the converter locks let of a bit at the shifts, always taking it easy until oil temps are up to full temp etc..
Then there are the giluys that when something about the engine is not running right their answer is todrive the piss out of it to se if that helps!?! I guess they think they will clean it out. Or they just keep driving it hard like kormal regardless of the pinging sound and extra smoke out the tailpipe.
My engine starts acting funny it gets limped home and parked till fixed. At the very least babied if its driven.
There is no doubt the 7.3 is not the strongest diesel out there but I agree I can see a number of these kabooms being driver/owner related.
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