Manley Billet 100mm crank - Cracked
Oct 8, 2018, 05:12 AM
#196
Evolved Member
Having a sharp edge on the oiling hole creates a stress riser. Stress risers greatly increase the likelihood of a cracking forming. Once a crack forms, even at a microscopic level, it will continue to grow until it reaches the other side. In this case the other side would be the other side of the journal.
Oct 8, 2018, 06:13 AM
#198
Having a sharp edge on the oiling hole creates a stress riser. Stress risers greatly increase the likelihood of a cracking forming. Once a crack forms, even at a microscopic level, it will continue to grow until it reaches the other side. In this case the other side would be the other side of the journal.
Yeah, im sure most are not familiar w/the term "stress riser". I work in the mechanical industry, so we reference those techniques as general practice
Oct 11, 2018, 07:29 AM
#199
EvoM Guru
iTrader: (1)
Kaboom.
Hard to tell from pic, but it doesn't look like this one started at the oil port pictured on the rod journal. May have been on the other side.
Hard to tell from pic, but it doesn't look like this one started at the oil port pictured on the rod journal. May have been on the other side.
Oct 11, 2018, 07:41 AM
#200
Two sides to every story. Maybe that engine had been rattled for a long time. Occasionally pump gas, timing and high boost get out of hand . Or its an auto x car that shakes the tires 100's of times with a QM. RS motors broke a few STOCK cranks with that setup. Eventually the weakest link will break. Big tires, built diff's, a strong clutch and a loose surface is a hard environment.
FWIW, TS comp has used 100's of the old style 100mm billet cranks for years with a high success rate. If he was running into issues, He would most likely chose another route.
Manley made the change recently and it should add even more strength . However, tuning and environment are still relevant IMO.
Oct 11, 2018, 08:43 AM
#201
Evolved Member
Maybe they should change their name from SLOWMOTION MOTORSPORTS to NOMOTION MOTORSPORTS?
Who in their right mind would name a performance shop Slowmotion Motorsports?
There’s another oil hole on the other side of the journal so it’s impossible to tell if that was the cause. I guess you could call them and ask?
Who in their right mind would name a performance shop Slowmotion Motorsports?
There’s another oil hole on the other side of the journal so it’s impossible to tell if that was the cause. I guess you could call them and ask?
Oct 11, 2018, 08:50 AM
#202
Evolved Member
Actually it does look like it came from the oil hole. If it would have cracked on the oil hole facing the camera it would have broken on the other side of the journal.
Oct 18, 2018, 08:55 PM
#204
EvoM Guru
iTrader: (1)
Smooth it out with a small bit on a dremel
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Kevin Troy (Oct 20, 2018)
Oct 20, 2018, 05:52 PM
#206
EvoM Guru
iTrader: (1)
Originally Posted by Kevin Troy
Nothing a dremel can't do.
by doing that, be precise and sober
by doing that, be precise and sober
Nov 26, 2018, 02:43 PM
#208
EvoM Guru
iTrader: (1)
Meanwhile, English Racing uses an Eagle forged 88mm to make 1400whp. Why do they use it? Because it's the only one that doesn't crack out of testing all the cranks at 1100-1200whp+...
