Strange noise...

[SoFloG]

I know it sucks but I'd pull the transmission and look at the converter, when I did mine the crack was barely visible but made sounds randomly. I'd have never guessed it if my buddy hadn't just went through the same thing. You could try hitting the flywheel with a hammer first, it should ring true if good, kind of like a tuning fork, would be off if cracked.

Awesome. Will get under with hammer and light. Unfortunateley another busy *ss day without a chance to get under there. Its' 40 degrees here in South Florida and it's extreme for people like me who do better in 90 plus weather.

 

[Texas82GP]

I've had the opportunity to see three cracked flywheels, all new OE Chevrolet, all brand new crate engines, two ZZ4's and one 290hp. All of them presented noises while idling or light load, starting or under power they would lock up the crack and you would hear nothing, all at/around 8K miles. All three were replaced with new SFI flywheels plus grade 8 hardware and never had a problem again.

Were they flexplates (AT) or flywheels (MT) or both?

 

[Wraith]

Were they flexplates (AT) or flywheels (MT) or both?

Just flexplates(I use the same word for both I guess), which was apparently what they did. 😕 I'll have to dig through the garage, I had the center of one and one complete one cracked all the way around.

 

[pontiacgp]

Were they flexplates (AT) or flywheels (MT) or both?

you just brought up a good reason to convert to a stick, flywheels don't crack and you have a variable stall rating...😎

 

[Texas82GP]

Just flexplates(I use the same word for both I guess), which was apparently what they did. 😕 I'll have to dig through the garage, I had the center of one and one complete one cracked all the way around.

That makes me feel better. I have a brand new GM flywheel sitting on the shelf for my build.

I think it is pretty common to refer to a flexplate as a flywheel. I was just wondering if I needed to think about sourcing a different flywheel for my build.

Were those GM flexplates that cracked made in China?

 

[Wraith]

I wish I remembered where they were made, at the time I actually went and bought the same one while I was waiting for the SFI rated one to come in, when it did arrive they weren't even close in quality. I think the SFI was cheaper to boot.

 

[fleming442]

All of them presented noises while idling or light load, starting or under power they would lock up the crack and you would hear nothing, .

Hmmm, that's exactly what the Pig is doing. Being a Series 2, I automatically assumed it to be a rod bearing. Taking bets......

 

[Wraith]

In my youth I also tore apart an excellent running 327 for what I perceived as a "rod knock". When I got inside everything measured good, found the rod knock when I pulled the timing chain cover, chain was so worn it was knocking against the cover.

 

[ItsnotaGN]

you just brought up a good reason to convert to a stick, flywheels don't crack and you have a variable stall rating...😎

But they can explode. When I was young and even dumber than now, I used an old Scheifer aluminum flywheel in a 65 Nova. On a 5000 rpm 2-3 shift it let go and I had aluminum chunks (scattershields are your friend) come through the trans tunnel.

 

[pontiacgp]

But they can explode. When I was young and even dumber than now, I used an old Scheifer aluminum flywheel in a 65 Nova. On a 5000 rpm 2-3 shift it let go and I had aluminum chunks (scattershields are your friend) come through the trans tunnel.

that is true and on a race car they are needed, on a street car I don't think I have heard of a flywheel coming apart and with the weight of my car the heavier steel flywheel is better accelerating from a stop