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Interesting theory. Do you have any evidence to support this claim?
Well any engine builder worth a pinch of $hit should knows this info. I suppose you could google it or something if your skeptical.
My own personal experiences I have seen this before with different engines and every single time there was a razor sharp edge where the crack emanated from the oil hole. Back in the day when crankshafts were ground at a local machine shop, the guy grinding the crank usually put a radius on the oil hole to prevent cracking and improve oil flow.
One particular engine was a small block crank in a basically stock pickup truck. That crankshaft should never have cracked at those low power levels.
Granted it’s always best to have that edge removed before the crank is heat treated but even if you remove the burr after heat treating it won’t crack.
I think you're correct. But China is no longer an automatic qualifier to say a part is junk. You can get quality parts from China, the company having the products made there just needs to ensure they are using the metals they specified, and that parts are being finish to design specs (heat treat, dimensions, etc).
I think you're correct. But China is no longer an automatic qualifier to say a part is junk. You can get quality parts from China, the company having the products made there just needs to ensure they are using the metals they specified, and that parts are being finish to design specs (heat treat, dimensions, etc).
Sean. Good to hear your positive comments on parts made overseas (China) (i.e. Fortune Auto).
Yeah, China can turn out some high quality items. I own a few expensive Chinese made pocket knifes that are the highest quality knifes i own
Sorry to the OP for being off topic but here it is (full Ti handles & belt clip / ceramic bearing pivot & blade steel spec S35VN)
I totally agree with you on Chinese quality. It can be very good. I don’t think the quality control checks are as good as some other areas of the world.
I believe the Manley cranks are extremely strong, they just are lacking as far as attention to detail is concerned. It has always been this way even with a lot of American made products in the past. Special things need to get done at final assembly to make them reliable.
There are a lot of things professional engine builders do to the parts they assemble, tricks of the trade, that make there engines “worth the extra coin $$$”
It has a lot to do with “failure analysis” and coming up with reliable fixes.
Seems like a lot of folks have the attitude, well these cranks break so they must be junk. We will try brand X instead. Years ago this wasn’t an option because much of the time the stock piece was all that was available. M2C
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 3, 2018, 12:32 PM
