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Flywheel cracks

intothelabyrinth

Active member
Joined
Mar 20, 2012
Location
Bowling Green, KY
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I got the engine and transmission out of the rusty parts car yesterday, and found the flywheel has little cracks all around it. Should I see about getting it resurfaced, or just go ahead and try to source another lh2.4 flywheel?

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My 740T looked like that before I had it resurfaced. After resurfacing it looked like that but shiny, maybe a few less lines on it. I used it anyway and it was fine.
 
Probably drove it with a slipping clutch for a while. Tha pours heat into the surface of the flywheel, the hot metal expands, the cold parts stay the same - it produces stress. And that in turn creates cracks.

If driven sedately - it's probably OK if resurfaced. But if you're going to continue to beat on it, cracks could propagate further, and on a 240 you can eyeball where your feet are in relation to the flywheel. And if it ever falls apart at high RPM (where it's most likely to) chunks of metal can and do rip straight on through the bellhousing and tunnel.
 
Probably drove it with a slipping clutch for a while. Tha pours heat into the surface of the flywheel, the hot metal expands, the cold parts stay the same - it produces stress. And that in turn creates cracks.

If driven sedately - it's probably OK if resurfaced. But if you're going to continue to beat on it, cracks could propagate further, and on a 240 you can eyeball where your feet are in relation to the flywheel. And if it ever falls apart at high RPM (where it's most likely to) chunks of metal can and do rip straight on through the bellhousing and tunnel....and chop off both your feet at the ankles...


Finished that for you.
 
Aren't they still cast iron stock ones just toofies for 60-2 machined in?
cast iron which grow cracks with hard use????

I understand the concern with heavy dog-dish flywheels and have avoided them but are we also concerned with the "flat" flywheels as well? I don't recall ever hearing of an issue with the flat ones. Also, iirc, most manual equipped vehicles have come with similar flywheels from the factory in the past and the most common reason people upgrade is for weight differences. Not arguing, just in for information as I currently have a flat flywheel that has been lightened on the backside and lh2.4 teeth machined in whirring beside my legs up to redline daily.
 
Finished that for you.

I was using the Socratic method.

Yeah, when I added aitch-peas to my 245's redblock, I took the dog-dish off and used one of JohnV's steel flywheels. Light weight, fits a 240mm Saaaab clutch (more diameter = better torque capacity with same pedal force), and won't fly apart and turn my legs into stumps. Well, a lot less likely anyhow.
 
But anyway, I'm thoroughly scared, and don't have $1,000 to throw at a flywheel for a daily driven stock turbo redblock... I guess the path of least resistance would be for me to just use the AW71 I have. Then at least I wouldn't be thinking about the flywheel grenading every time I get on it.
 
I don't recall the steel flywheels costing $1000, but maybe if you include the price of a super-spiffy clutch.

How are you going to use it?
 
Like a semi-sane person... I plan on just using it around town to get to work...on the highway some. No racing. Stock 1993 B230FT with 13C and maybe 10psi in a 1988 245. I wouldn't be beating it to redline, but it would prob see 5K rpm regularly.
 
The steel Yoshifab lh2.4 flywheel and clutch/pressure plate setup is $1,050. That STS Machining lh2.4 flat flwheel is just an old cast iron flat flywheel that has been machined for lh2.4 and balanced/resurfaced. It's about $280.
 
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