I may be THE FIRST.... Nah, I can't be...
- Thread starter RogueCustoms
- Start date
I wander what the #1 and #2 main bearings look like? If the load wasn't even between the two it might cause it to crack?
supra13's;1877450 said:
#1 bearing is down to the copper and #2 looks almost perfect. I had the bottom end rebuilt less than 15,000 mi ago. My oil pick still looks brand new!!! It's crazy.
Starting to gut the bottom end today. Pics to come!! I know how you are all looking forward to it.
The only guy I've heard of who has damaged a crank is Mibrum on his rail dragster, and even that didn't break, it twisted, IIRC. And that car is, well, a bit above 425 at the wheels. ;-)
As I said earlier... I grew up with the Hot Rodders, gear heads, and muscle. I've never heard of a crank breaking or cracking... But, it would happen to me. I love my MKIII... I don't quite know if it has the sentiment...
this rail dragster at 425?
[video=youtube;9loVGkCVQ-M]http://www.youtube.com/watch?v=9loVGkCVQ-M[/video]
[video=youtube;9loVGkCVQ-M]http://www.youtube.com/watch?v=9loVGkCVQ-M[/video]
Quoting from memory here... something about fuel washing past the rings and contaminating the oil, so he didn't have enough lubrication on the crank.te72;1877909 said:
Guilty as charged.Angry7M;1877948 said:Ahh I believe he was trying to be sarcastic "well above 425 at the wheels"
The theory behind it is actually quite simple. Pass a magnetic field through a chunk of metal. The field is quite happy flowing through the metal, but not so happy flowing through air. Now, spray iron dust on the part. The magnetic field is happier with metal to flow through, so where ever there is a crack, the magnetic field will attract more of the iron dust to fill the crack.Orion ZyGarian;1877997 said:
Not an entirely accurate explanation, but it's simple enough that the layman can understand it.
I was being a bit facetious, for the record :biglaugh:
It is a very simple concept, but still really cool to watch and learn about
It is a very simple concept, but still really cool to watch and learn about
We had a box with a kit of it at my last job. Not quite sure why, as it isn't really something that would come up at our little operation, but I always did want to play with it. Can't imagine it is cheap enough to be "playing" with though...IJ.;1878395 said:Got the guided tour at my Crank shop and watched it in action, cool stuff
MPI consumables are dirt cheap. Costs a bit to get into for the backyard mechanic though.
If the crank didn't fail due to a casting flaw that was brought out of hibernation by increased engine ou, its possible that the machinist managed to gouge the fillet radius of the journal creating a stress riser. Stress riser = fatigue crack. How long had that crank been in the engine since last rebuild? 10^7 fatigue cycles is around 55 hours at an average of 3000 RPM.
If the crank didn't fail due to a casting flaw that was brought out of hibernation by increased engine ou, its possible that the machinist managed to gouge the fillet radius of the journal creating a stress riser. Stress riser = fatigue crack. How long had that crank been in the engine since last rebuild? 10^7 fatigue cycles is around 55 hours at an average of 3000 RPM.