There is, if you have a stand alone Bosch ecm and the knowledge on how to use it. For the common man, swapping the harness when installing the cam works well. No further tuning needed.
Cranks
- Thread starter Fingers
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There is, if you have a stand alone Bosch ecm and the knowledge on how to use it. For the common man, swapping the harness when installing the cam works well. No further tuning needed.
The LMM OS has some funky rationality checks and in it. For instance, if it senses more than 4 degrees difference in the orientation of the crank at TDC and the cam position sensor trigger, it will prevent the engine from starting.
As far as the Dmax firing order goes, it is basically the classic 4-7 swap of a small or big block chevy. It seems different because the cylinders are numbered differently between classic V-8 Chevy and Dmax.
The 4-7 swap was originally done to help with cylinder filling. With 18436572, cyls 5 and 7 right next to each other, cyl 7 didn't fill as well in normally aspirated open plenum style intake manifolds.
The firing order I use (and what Jon has concluded) is the current Chevy LS engine firing order.
When we first started this in early 2010, I asked EFILive about it and was told that the firing order was hard coded into the OS. No table existed that would allow us to change the order.
The Bosch racing software will allow you to enter any order you like. :thumb: You can also change the orientation of the crank reluctor wheel relative to TDC in the software. I had a customer install his reluctor wheel 90 degrees off and we just rewrote the parameter in the Bosch software. :woott:
Whats different about the cylinder numbering?
I should have never read this thread Lots of good info here keep it coming:thumb:
Lots of good info here keep it coming:thumb:
I wonder if some LBZ OS also have this.
When I first broke my crank (behind the #4 main) I could still fire it up and it would run and bang like hell, but still ran.
Each time I did this, and the noise got worse, it would start and then all of a sudden it would no longer start. It had a code for the crank sensors being out of sync with each other or something like that.
That's normally how they all are
Very good reading! Now this will probably come back to get me but here goes! Why has my motor not broken a crank yet? It leaves the line at 4000 shifts at 5100 and see's 5400 in the lights. It's the crank from my white truck that I bought new and has been raced since day 1. That crank has to have passes in the quarter mile than just about everyone here together! It has been at 900 to 1000 hp or better it hole life. I run Guys cam and balancer and always have since day one. I also run a very light piston (748 grams) light rods (1098) and had a very good shop do the balance that didn't just balance it to a 50/50 balance. I broke a flexplate at BG race in the lights and it shook like a queer eating a dot dog at over 5000 rpm and all was good when I looked at the bearings. It just should not have lived after that!!! It should have been in 2 pieces. I wish we had the answers but I think it's more with harmonics/vibrations than anything. If it were block or crank alignment you would see it in the bearings. Now I pry to god this thing doesn't spit the crank out of it now the next time I run it. LOL Jeff
Keep up the work all that are trying to figure it out! Anything that anyone learns will only help out everyone with these money pits!
Maybe your high rpm is taking enough load off the engine?
More RPM is more inertial load, creating more load on crank. Depending on weight of assembly,and RPM this inertial weight can be higher than 10,000 lbs per rod throw.
Piston weight in grams includesiston Piston Pin Rings Pin Retainers
You can see the effect of what a different rod length, Stroke, weight, or RPM will have on the rotating inertia of your engine.
Piston Weight: 1300 Grams
RPM: 5000
Stroke: 3.900 Inches
Rod Length: 6.420 Inches
Your AVG Inertia Force per rod is 3,968.80 pounds.
Your Stroke/Rod Ratio is 0.30 .
Your Rod/Stroke Ratio is 1.65 .
Effect of Rod/Stroke on TDC and BDC inertia force:
Your Upward Inertia Force per rod at TDC is 5,174.27 pounds.
Your Downward Inertia Force per rod at BDC is 2,763.32 pounds.
I just plugged in a few #'s for demonstration. only.
iston Piston Pin Rings Pin RetainersYou can see the effect of what a different rod length, Stroke, weight, or RPM will have on the rotating inertia of your engine.
Piston Weight: 1300 Grams
RPM: 5000
Stroke: 3.900 Inches
Rod Length: 6.420 Inches
Your AVG Inertia Force per rod is 3,968.80 pounds.
Your Stroke/Rod Ratio is 0.30 .
Your Rod/Stroke Ratio is 1.65 .
Effect of Rod/Stroke on TDC and BDC inertia force:
Your Upward Inertia Force per rod at TDC is 5,174.27 pounds.
Your Downward Inertia Force per rod at BDC is 2,763.32 pounds.
I just plugged in a few #'s for demonstration. only.
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Here is only 4000 RPM inertial weight on crank.
Piston Weight: 1300 Grams
RPM: 4000
Stroke: 3.900
Rod Length: 6.420 Inches
Your Inertia Force per rod is 2,540.03 pounds.
Your Stroke/Rod Ratio is 0.30 .
Your Rod/Stroke Ratio is 1.65 .
Effect of Rod/Stroke on TDC and BDC inertia force:
Your Upward Inertia Force per rod at TDC is 3,311.54 pounds.
Your Downward Inertia Force per rod at BDC is 1,768.53 pounds.
Piston Weight: 1300 Grams
RPM: 4000
Stroke: 3.900
Rod Length: 6.420 Inches
Your Inertia Force per rod is 2,540.03 pounds.
Your Stroke/Rod Ratio is 0.30 .
Your Rod/Stroke Ratio is 1.65 .
Effect of Rod/Stroke on TDC and BDC inertia force:
Your Upward Inertia Force per rod at TDC is 3,311.54 pounds.
Your Downward Inertia Force per rod at BDC is 1,768.53 pounds.
wow....:hug:
Ok, so alt fire cams may help reduce harmonics that possibly are the cause of damage to the cranks. Cool.
Lets keep it on topic about cranks here as per Fingers original discussion and leave the pissing match out of it-or start up another thread about alt fire cams maybe seeing as they are getting more discussion now.
Thanks.
Lets keep it on topic about cranks here as per Fingers original discussion and leave the pissing match out of it-or start up another thread about alt fire cams maybe seeing as they are getting more discussion now.
Thanks.
This thread is about Cranks, their failures and what might be the root cause there of. Solutions welcome, keep the politics to yourself.
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Piston weight in grams includes
You can see the effect of what a different rod length, Stroke, weight, or RPM will have on the rotating inertia of your engine.
Piston Weight: 1300 Grams
RPM: 5000
Stroke: 3.900 Inches
Rod Length: 6.420 Inches
Your AVG Inertia Force per rod is 3,968.80 pounds.
Your Stroke/Rod Ratio is 0.30 .
Your Rod/Stroke Ratio is 1.65 .
Effect of Rod/Stroke on TDC and BDC inertia force:
Your Upward Inertia Force per rod at TDC is 5,174.27 pounds.
Your Downward Inertia Force per rod at BDC is 2,763.32 pounds.
I just plugged in a few #'s for demonstration. only.
These equations are not exact And would be higher as the recipricating end of the rod and rotational end of rod are not taken into consideration. Also worthy of note is the added combustion pressure on the way to BDC and compression on the way to TDC. The dynamic #'s would baffle most.
Don't know how much this adds to the discussion, but i saw this blurb on the Confederate Diesel site along with the pictures of the bearings:
"Here are some bearings from a bent crank. This happens to stock engines and as well as 1200 hp units. Internal balanced cranks, and external balanced cranks. The failure has always been at #2 main bearing area in every case. Some have been detected early such as this case where the crank on v blocks has bent .004" . The root cause has yet to be determined.
http://catalog.mahleclevite.com/bearing/ is a good technical guide"
See: http://www.confederatediesel.com/duramax-crank-failure.html
"Here are some bearings from a bent crank. This happens to stock engines and as well as 1200 hp units. Internal balanced cranks, and external balanced cranks. The failure has always been at #2 main bearing area in every case. Some have been detected early such as this case where the crank on v blocks has bent .004" . The root cause has yet to be determined.
http://catalog.mahleclevite.com/bearing/ is a good technical guide"
See: http://www.confederatediesel.com/duramax-crank-failure.html
Internally balancing has not been a solution.
F
Fahlin Racing
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Not sure how much pressure we produce within these engines, but, here is an example from EPI inc on their website concerning diesels and their Contemporary Crankshaft Design article.
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