Suprise 4A failure.

[ViPeR_NiPPleX]

It was probably my driving that started it

Thats a ripper of a sheared crank nose. Too much tension from one or more ancilleries?

[Hen]

Viper - Yes, it was your driving that caused it... now when will you be rebuilding it??

As for belt tension, it's varied over the years, but just tightened by hand til it felt right. Fatigue from the belt load is the only thing that makes sense currently.

5pk belt - 1
Forged steel crank - 0

Hen

PS, TA-022, even though I had a mega-hyper-doopa-sonic BOV on it, for some reason it had no dose, flutterz or psssshhhhht. Any idea what was wrong?

[ViPeR_NiPPleX]

I guess that other motor will be going in sooner than expected?

[TooF]

either that or just stress from the keyway has casued a small crack which has obviously progressed. my failed crank the keyway was pretty chewed up so it would sprise me that it could crank from there.

[Joshstix]

That doesn't look like a stock rubber isolated damper/pulley.

[Jonny Rochester]

I have worked at a Toyota dealership and this is a known problem. I have seen a few 4A-FE do the same thing, broken crank in the same place. Our dealership kept a few 4A block/crank/pistons assemblies in stock at the time a few years ago.

[Hen]

...this is a known problem. I have seen a few 4A-FE do the same thing, broken crank in the same place...

Warranty!!!!

"Hello Mr Toyota, the crankshaft in my grandma's AE93 Corolla broke. Yes, she was just driving to church..."

[Rallystanza]

Benny, I still think its a possibilty and also reading Joshstix comment about the pulley not being the rubber isolated stock one, but i think, perhaps that pver time there has been something out of balance and and this started a hairline fracture that has eventually led to this. The stuff didnt look rusty when I saw it on saturday...

Lets get the new engine going, the SC14 equipped 4whYE is almost done yeah?

[roadsailing]

are the ZE pulleys isolated? i know the GE one is just solid cast iron (on my engine anyway)

[Rallystanza]

Im pretty sure the GZE ones are isolated Will, this one was a turned alloy one with a larger diameter for more flutter, A dose pipe of the supercgarger world if you will.

[MRMOPARMAN]

i reckon the best way to fix this problem would be to turbo that sucker

[Hen]

... the pulley not being the rubber isolated stock one... perhaps that pver time there has been something out of balance and and this started a hairline fracture that has eventually led to this.

An out of balance pulley won't cause cyclical stress on the crank. Because it is fixed to the crank, it'll just cause a load in one direction depending on revs. So no cycling means fatigue isn't an issue.

Belt load will cause cycling stress in the crank though.

... The stuff didnt look rusty when I saw it on saturday...

Good point. I hadn't remembered that.

... the SC14 equipped 4whYE is almost done yeah?

Nah the 4whythefuckdidieverinstallthisengineE is waiting on a T88-34D. New 4A wont be too long I hope.

[Joshstix]

The stock pulleys are rubber damped to act as a harmonic dampener. Not saying the fact you had a solid pulley caused this through harmonics but I'm sure it didn't help.

[YLD-16L]

Pretty sure my stock RWD bigport pulley is solid, my old ZE pulley was rubber damped. I'll check the pulley tonight to confirm.

[Joshstix]

Interesting. I have only really seen FWD ones, GE and GZE and they have all had rubber in them.