NDT is quite common in my area. Everything from pipeline to crane inspections and structural or pressure vessel welding has to have it done by law to be certified so I'm familiar with it also. It's amazing what a mag test won't pick up but an xray or other NDT test does.
Broken Crankshaft Alt Fire Cam
- Thread starter S Phinney
- Start date
I'm sure it would be a great too to have in the diesel racing world if it were cost effective haha.
We do UT testing also on some parts. I bet a UT could be used on a crank still sitting in the block, that's how we do some of our stuff.
We do UT testing also on some parts. I bet a UT could be used on a crank still sitting in the block, that's how we do some of our stuff.
Still have yet to see a new crank with af cam fail nobody has proof otherwise.... seeing this I'm going to wait till I break my crank then get a new one and af cam same time. I still think it's a great help maybe not a permanent solution for huge hp but for the 900 hp and less crowd I bet it will be
Nobody said that, we were talking about NDT testing vs magnafluxing. Magnafluxing only shows surface cracks where NDT shows micro cracks even at the core of a dense metal object.
NDT as in Non destructive testing. There are several forms if it. It was tested other than magnafluxing. I figured there may be some opinions that since it wasn't a new crank that it really wasn't relative. Maybe Jon will post some opinions about it. I talked with him the other day about this at length.
Does anyone talk to nwpadmax still? Matt knows a hell of a lot about metallurgy, and is who I would be asking for help on this. Heck, if we could combine Finger's knowledge of stresses and Matt's metal skills, we may come up with possibilities.
Good conversation. Hopefully the right guys can come together on this and a reasonably priced solution is found. 4k for a crank would send me out of the sport.
Please don't tell me, that being a used crankshaft has no bearing or implications here.... I deal with this everyday with our own products, which go on commercial aircraft, U.S. Naval ships, and drill rigs here in the Gulf just to name a few. Being used "cycled" changes everything... I would be curious to hear his thoughts too. I mean I'm still learning all this myself. And certainly open to other opinions. But I machine, design, inspect, edm, you name it, with many many different materials everyday. I can't tell you how many times I've turned a vessel (316L) sent it for certs everything comes back perfect. No micro inclusions. Customer uses in field for 5 years, sends in to be rebuilt (cut open re packed) re certified, vessel fails inspection. Micro inclusions found... Being used changes everything.
Sucks you broke a crank tho. Don't want you to think I'm being a jerk or anything. Just feel strongly about it being used is all.
Yeah, well it sounds like you had your bases covered as far as you reasonably could, NDT or "magnetic particle testing" is like magnafluxing it just goes further. The only other thing you can do is Ultrasonic testing which goes all the way to the core but that just isn't practical in this particular application.
We do UT testing on big grip axles for ski lifts and they are as dense and have the same diameter as a crank main or rod journal which NDT would not pick up micro cracks on because it's just to dense
I understand what you are saying. I can tell you that I don't know everything. I wish that it hadn't happened but it did. Why? I am not sure why and can only estimate just as everyone else. I shared this hopefully for the purpose of learning and exploring more ways to make things better if possible for us. Most guys won't tell you that they had a problem. I don't have a problem being honest with it.
I am sorry that it habbened but i do appreciate you talking about it, I'm very interested in metallurgy, its an interesting subject and its made me a lot of money over the years :thumb:
I certainly appreciate you being honest and coming forward with problems and hopefully a solution. I couldn't possibly afford to go thru several dmax builds. I'm glad we have a bunch of smart and reasonable guys on here to help figure out what's going on.
The dmax is common rail
Or do you mean a cumapart
Sorry I refer to Cummins as Common rail. Lol
Thanks Shane
Most won't talk about it so thank you! I sometimes would rather have a used piece than a new one. New doesn't mean better sometimes. My old LBZ crank was beat on from new in 06 to last year and finally cracked. I put a LB7 in this time because Fleece wanted it that way and they internally balanced it. We will see how well it holds up. Shane is dead on with the block and crank centerline and what we are asking from these things. I think keeping the rpm's up and TQ down will go a long way in keeping it in one piece.
Most won't talk about it so thank you! I sometimes would rather have a used piece than a new one. New doesn't mean better sometimes. My old LBZ crank was beat on from new in 06 to last year and finally cracked. I put a LB7 in this time because Fleece wanted it that way and they internally balanced it. We will see how well it holds up. Shane is dead on with the block and crank centerline and what we are asking from these things. I think keeping the rpm's up and TQ down will go a long way in keeping it in one piece.
The technology exists to find internal flaws, as has been mentioned above. Ultrasound would be one good route to go. The trouble with UT in this case is the irregular shape of the part. Round shafts are duck soup, but we already know the failure is happening at the very edge of the journal and into the throw.....that is where the hard part is. Yes there are handheld UT units that you can use on shafts and simple parts. We used one in our plant for years until we upgraded to an immersion unit.
I am sure there are people set up to UT cranks. It is FAR from simple unless you have very specific setups where you can shoot the areas of interest and not get a complete bullshyt signal back. Then you have to have a standard to estimate a flaw size based on the amplitude and timing of the reflection. The technology is easy to understand but the application can be mind numbing.
But here's the bottom line. Unless you have a crack, UT doesn't show you anything. Nada, zero, nothing...until it starts. So the practicality of finding a crank that is just starting to fail and getting it UT'd is very low. Especially when the cracks appear to be originating at the surface (which makes some sense to me). It's entirely possible that the core of the crank is at a lower stress state and finding voids or cracks there could be almost meaningless.
One of the effects that Fingers postulated that still rattles around in my brain is the unsupported load at the end of the crank. If that is one of the main root causes, alternate fire may help but not completely solve the issue.
And yes the life of the crank will definitely contribute. A brand new crank in an alternate fire setup could last longer, but you'd have to run some extensive experimentation to prove that beyond a shadow of a doubt. A sample of 1 or 5 or 10 ain't gonna be enough to get statistical proof, especially when a lot of those setups are in pullers that have maybe 30 minutes of high power run time per season....
Just throwing out ideas.
I am sure there are people set up to UT cranks. It is FAR from simple unless you have very specific setups where you can shoot the areas of interest and not get a complete bullshyt signal back. Then you have to have a standard to estimate a flaw size based on the amplitude and timing of the reflection. The technology is easy to understand but the application can be mind numbing.
But here's the bottom line. Unless you have a crack, UT doesn't show you anything. Nada, zero, nothing...until it starts. So the practicality of finding a crank that is just starting to fail and getting it UT'd is very low. Especially when the cracks appear to be originating at the surface (which makes some sense to me). It's entirely possible that the core of the crank is at a lower stress state and finding voids or cracks there could be almost meaningless.
One of the effects that Fingers postulated that still rattles around in my brain is the unsupported load at the end of the crank. If that is one of the main root causes, alternate fire may help but not completely solve the issue.
And yes the life of the crank will definitely contribute. A brand new crank in an alternate fire setup could last longer, but you'd have to run some extensive experimentation to prove that beyond a shadow of a doubt. A sample of 1 or 5 or 10 ain't gonna be enough to get statistical proof, especially when a lot of those setups are in pullers that have maybe 30 minutes of high power run time per season....
Just throwing out ideas.