Ouch!!!

And I thought the FIRST set of pictures were scarey enough.
EGADS man! Hair on back of my head, (what little there is), is just standing on end, looking at those.............DAmm, damm, damm. [img]/phpBB/images/smiles/icon_frown.gif[/img]
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NEVER push a stock iron flywheel very hard.

Those things are bad about heat cracking.... and when they start to go, they GO!

Steel flywheels are pretty much the best thing to happen to stickshifts since people started racing. [img]/phpBB/images/smiles/icon_frown.gif[/img]

Guys, just remember to align those aftermarket steel bellhousings. They aren't all that precise, as they are just a hydroformed steel plate.

Good Luck!
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On 2005-03-18 20:03, n2omike wrote:
NEVER push a stock iron flywheel very hard.

Those things are bad about heat cracking.... and when they start to go, they GO!

Steel flywheels are pretty much the best thing to happen to stickshifts since people started racing. [img]/phpBB/images/smiles/icon_frown.gif[/img]

Guys, just remember to align those aftermarket steel bellhousings. They aren't all that precise, as they are just a hydroformed steel plate.

Good Luck!

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I agree about the alignment of the bellhousings, the Lakewood on my IMCA Modified was about .070 " out of being on center, and I have seen worse. I think if you are going to rev something past 6500 RPM, an aftermarket fly wheel and bellhousing would be a wise addition, but they are a pain to install correctly.

Wow, that reminds me of Kunta Kintay and Don Garlits!
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I have to admit, I didn't check the alignment on my Lakewood and I even had the tools at my disposal to do so... but the weekend I intalled the Tranny (the night actually) was right after my girlfriend broke up with me and I just wanted to make some major progress since I had been neglecting the project while we were dating... but roughly 15,000 miles later and still no problems, so guess maybe I was one of the lucky ones that the bellhousing lined up OK. What are the symptoms of a poorly alighned bellhousing? Seems like it would put some side-load force on the tranny input shaft and also cause the clutch to vibrate and front bearing in the tranny to wear out prematurely.
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Thats why we posted the Big Bang article when it happened to my '65 Coupe. I , too, am fortunate to still have two feet and ten toes.


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I wonder if my belhousing was slightly out of alignment. That engine saw that kind of rpm several times with the old RAM clutch. This was the first time I spun it that high with the new Centerforce clutch though. I did have the Centerforce balanced before I installed it. Anyone have any theories or input?
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Cast Iron flywheel! That would be my 1st guess.

If you just want to be sure...see if you can collect as many pieces of the old flywheel as you can. Take a good look at the size of the pieces and pattern of how it cracked. That will may give you an indication of what let go first. The clutch plate is still intact, the clutch hat may have been hit by recocheting scrapnel. So that leaves the flywheel.

If its the bellhousing, there should be torsional, stress cracks near either the bolt holes (tranmission, block..) If they are relatively intact, most likely thats not the root cause.

Although I can see where bell housing alignment can be a contriuting cause. Take a look at the pilot bearing, is it intact, still in the crank?

Though it may look likehigh science, it really not, just like the FAA has discovered over the years; every failure leaves a trail, Failure analysis is not majic...it's just taking a detailed look at whats left and logically stepping through the trail following, decoding from marks on the damaged pieces.

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Cast iron flywheel.

Stock cast iron flywheels should NEVER be pushed that hard. They are FAR to crack prone to go 7800 rpm.

A steel flywheel is definitely worth the additional expense.

Good Luck!
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Here's a couple more photos. These are the pieces I could find. I still get the chills when I go out to the garage.








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