O.E.M. flywheel/clutch max rpm

[pclowes]

What is the max rpm of a factory iron flywheel?   I'm assuming that Ford offered nothing other than the regular cast iron flywheel.  Anyway that's what I have.  Anybody know if Ford offered anything else; maybe a nodular iron flywheel?

Started thinking about that as a weak link for the possible 6500rpm project that I'm constructing in my head.  I'm reasonably sure that an iron flywheel is not safe at that rpm (probably a buzz saw in waiting) but looking for others thoughts.

While I'm at it what about the rpm limits of the rest of the stock clutch (pressure plate and disc)?

[WConley]

I would never recommend using a factory iron flywheel in any performance application.  They were kind of OK when new, but 40 years of heat cycles will result in cracks.  Then BOOM when you least expect it.  New steel flywheels are not expensive especially compared to hospital bills!

A new performance pressure plate is a good idea too.  It's amazing how much energy is stored in a flywheel when you get up above 5,000 rpm.  Ford Livonia Transmission used an outsource lab to test flywheels to explosion in a "spin pit".  Generally a new iron flywheel would go 13,000+ rpm before blowing the heck out of the wood pit liner in the pit.  Old ones were known to fare much worse, with unpredictable results.  I understand it was dangerous testing, with the lab being badly damaged at least once...

I personally saw a flywheel come off a 3.8L supercharged V6 on the Ford dyno.  It sawed a deep groove all the way up the cinder block wall and half way across the ceiling of the cell before it stopped!

Don't mess around with flywheels and clutches!

- Bill

[pclowes]

Kind of knew that.  Just needed to hear someone else affirm it.  Don't want to end up like Garlits.

Thanks.

[cjshaker]

This is a video of an FE Forum members Boss 429, dynoed 6 years ago....using a cast flywheel because they didn't have a steel one handy.

It literally destroyed the engine and sent a chunk of flywheel through the concrete wall and into the adjacent room. I don't think your body would fare as well. Don't even think about a cast flywheel!

https://youtu.be/vq5cjNhN_po

[Heo]

A friends father told us about when he was driving a old Road roller with a big
flywheel on the side and the flywheel came loose. I snapped trees on its way
in to the woods They had to bring a catepillar with a winch to bring it back
on the road

[wayne]

I lost one in a small block at 4000 rpm and got lucky it went down and to the right broke the 4 speed block and cut the collector off the header that was 45 yrs ago. Run the good stuff it worth the cost.

[ScotiaFE]

This mind project, is it a street type deal or drag race or street/strip?
If your going drag racing with a clutch you may want to consider
an aluminum wheel.
Not the best plan for a heavy car at low speed, but
they give a much softer hit at the line. Which helps with
traction and reduces the chance of ripping stuff off the car.
If this is a street deal than a steel wheel will be a much smoother
ride at low speed.
What type of clutch are you considering?

[cammerfe]

The factory flywheel on my '64 Custom/427 held up just fine---but---I pulled the face of one side of the disc after I switched from the 4.11 to a 3.50 to make a trip a little more livable.

KS

Adding---all this time later---I'd never use a cast iron flywheel for any performance purpose now. Back then---Who knew??? I did a lot of dumb things back then.

[ScotiaFE]

The factory flywheel on my '64 Custom/427 held up just fine---but---I pulled the face of one side of the disc after I switched from the 4.11 to a 3.50 to make a trip a little more livable.

KS

That is true Ken and the cast wheels I used for years are still sitting in the shed.
And they are in great shape.
And in the days of yore an 11 second car was a fast car.
Today that is not a fast car not for a street car.
You can not run a cast flywheel if you go under 11.50.
The car needs a SFI flywheel and bell.
If you are hovering around the high 11 low 12 then you need the safety.
I could not imagine letting it rip today with a cast flywheel.
And I run 12 because that's what I can afford. 
And it costs me a lot.

[pclowes]

This mind project, is it a street type deal or drag race or street/strip?
If your going drag racing with a clutch you may want to consider
an aluminum wheel.
Not the best plan for a heavy car at low speed, but
they give a much softer hit at the line. Which helps with
traction and reduces the chance of ripping stuff off the car.
If this is a street deal than a steel wheel will be a much smoother
ride at low speed.
What type of clutch are you considering?

It's just a street car (58 Ranchero) so I am planning on using a steel flywheel.  Not sure about the clutch. Looked a little at what Mcleod has to offer.  Any suggestions?

[machoneman]

More on that blown up 'wheel on the Boss 429:

 http://www.network54.com/Forum/74182/thread/1252775447

 

[machoneman]

Here's my almost-got-killed story from that same link above from 2009:

Reminds me......   September 13 2009, 9:08 AM

At Union Grove Raceway in WI (about 1977) we had been standing about 400 feet behind the line next to the front of my buddy's new rear engined dragster. A '57 Chevy with a Lakewood 'bell had just started up and idled by us. We paid no attention but just as he rolled by the five of us, about 8-10' past nose of the dragster  where we were standing, he revved it and dumped the clutch (notwithstanding the fact that behind the line burnouts were prohibited). Zing! We heard a strange noise wiz past us and go off into the adjoining farmer's field.

Turns out our idiot blew the clutch, separated the bell & dumped the back of the motor on the track. Zing sound was clutch and flywheel (easy 60 lbs.) exiting underside and making tracks into the field. Randy Migut, our owner/driver of the then new dragster, just about killed the Chevy owner. We then called "Broadway Bob" Metzler (track owner) out of the tower, pointed to the mess and the smoking car and asked him to kick out the driver/owner. He did...for life!

To this day, I get the shivers when I recall just how close we came to getting killed that day.

[e philpott]

I blew a factory flywheel in a 289 hi po at around 7300 rpm back in the early 80's with a passenger in the car .... didn't get hurt but it broke everything , bell housing , block bell mounting tabs tore off , ripped a hole in my T10 , split a cylinder wall , tore the nose off the starter , destroyed clutch assembly .... very expensive for a 22 year old living on his own , car was down for a couple years