Flywheel safety?

It does Look heavier then a Lawn Mower Flywheel .
Still I'd say its a Risk . I think you're RPM range is up there in the danger zone .
 
Thank for info. Hope someone else has seen these before because they look and feel pretty good. I can guarantee one thing I have spun a clone flywheel up pretty foolishly and these have to be 1000 times tougher than those junkers.
 
ran 9700 on limited back in the nineties like everyone else with the stock flywheel WKA never had an issue then.
 
J'-remy said:
ran 9700 on limited back in the nineties like everyone else with the stock flywheel WKA never had an issue then.
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That's up there buddy. Although I am looking into this aluminum flywheel that is not billet but also is not the off balance mower blade flywheel. Take a look at the photo I posted up north a bit.
 
I don't know anything other than the stock 5hp raptor flywheel was mandatory in 96,97,98 when I ran it back then. the only billet flywheels I ever saw were on George Owensby 'Rocket Man' open engines and the flywheels had no fins. I have seen plenty of flatheads that blew the cylinder off but never saw a flywheel let go. A small engine repair man in Milwaukee told me the stock flywheel would hand grenade at 10,000 RPM. that being said my flywheel was new, never dropped, hit with hammers, wrenches stuck in fins or abused. I have a factory flywheel holder and a factory pull starter wrench. I cannot say the same for any used parts in your possession. the safest bet is to get a new billet trick unit. if I ever rebuild mine it will have an ARC unit for sure.
 
I wouldn't trust that flywheel at all.
Keep in mind that these flywheels are static balanced to the rotating ass'y they were originally cast for use with.
One flywheel explosion is not worth whatever savings there could possibly be in my opinion.


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🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
32 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
Hi, im new in small engines briggs, im a mehanic but i work on japan motorcycles, and i am in europe… i have a 8hp and i want to put a 3 hp aluminium flyweel on it, i can do it no problem, but reading the forums you got me wondering is that safe? I got a iron flywheal on the 8hp and i was thinking that wood be sweat trotle responce… btw ewerything is polished up ported , the head is lovered, the gowernator is outh…every trick i know. its going on a offroad go kart.
Thanks for the answers in advance.
 
CarlsonMotorsports said:
I wouldn't trust that flywheel at all.
Keep in mind that these flywheels are static balanced to the rotating ass'y they were originally cast for use with.
One flywheel explosion is not worth whatever savings there could possibly be in my opinion.


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🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
32 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
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Hi i wod like to hear jour opinion on mine idea
 
Marko B. said:
Hi i wod like to hear jour opinion on mine idea
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If it is an aftermarket billet flywheel, then go for it. It will work great for exactly the reason you gave.
If it is a stock cast flywheel, I would not take the chance.

ARC billet flywheels are tested and rated for SFI standards of safety.
Cast flywheels are only safe to around 6000 rpm (or approx. twice the intended usage rpm.)
If you've ever seen pictures of a flywheel explosion, you would never take a chance on one.


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🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
32 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
I've blown the cast aluminum fly wheels off of an open modified Briggs flat head within 2 warm up laps.... We were normally turning 10,000-10,200ish rolling with either the iron 3 or 5 horsepower wheels but the new ultralight flywheel lit the tires on the still fairly wet track at first practice and pulled a David Copperfield maneuver about 1\2 way down the back off of turn 2.

The tach recall showed I think 14,800 if I remember correctly, there were several witnesses watching when I hit the recall and my ears popped from them gasping in air... Lol.

I'm sure the actual RPM was lower and the tach caught some errant arcing during the ancillary damage caused by the shrapnel but everyone thought I actually had been turning the engine that hard anyway so I let em run with it. :)

Pretty amazing how efficiently the explosion of the wheel flattened out the blower tin. Lol.

Ended up just building my own billet aluminum flywheel after that and redneck engineering a backyard crank triggered ignition with an HEI module, hall effect switch, and an old MSD coil made for TBI setups.... Worked pretty good actually.... A lot of work and tweaking, but back then there wasn't much out there for an aftermarket selection for open modifieds.

That engine had a "Old Man Kelly" camshaft in it.... Someone on here will be able to metriculate a date off of that information. Lol.
 
Carson Kelly #38 back in the 80's 🏁 😁
 

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CarlsonMotorsports said:
I wouldn't trust that flywheel at all.
Keep in mind that these flywheels are static balanced to the rotating ass'y they were originally cast for use with.
One flywheel explosion is not worth whatever savings there could possibly be in my opinion.


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
32 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
Click to expand...
Not to bring up old stuff. But i cant help but think that same thing would be true for the ones we have used for years well above their static balanced rpm. Of course the steel ones are obviously able to out perform that engineering threshhold but was it ever actually designed to do so or did we all jist just happen to get lucky? Again Brian im not questioning your knowledge or experience on a person level, but more of a general thought based off of your quite scintific explaination. Also what was the model 13 cast steel wheels static balanced to be used with exactly i wonder? Was there slighty different wheels for differnt applications possibly? Idk just thinking with my fingers today i guess.
 
FlatheadsForever87 said:
Not to bring up old stuff. But i cant help but think that same thing would be true for the ones we have used for years well above their static balanced rpm. Of course the steel ones are obviously able to out perform that engineering threshhold but was it ever actually designed to do so or did we all jist just happen to get lucky? Again Brian im not questioning your knowledge or experience on a person level, but more of a general thought based off of your quite scintific explaination. Also what was the model 13 cast steel wheels static balanced to be used with exactly i wonder? Was there slighty different wheels for differnt applications possibly? Idk just thinking with my fingers today i guess.
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Stock cast iron flywheels have been known to exceed 10,000 rpm. When one came apart and killed a man is when limiteds and opens were mandated to use billet flywheels.
Typical engineering for years (at least in the US) is to design products to withstand twice the stress (rpm) as they are intended to be used at. This is important for liability reasons for the company that produces and sells them. The stock flywheel was intended to be used on a governored engine running around 3600 rpm. They can (and regularly do) turn up well above 7200 in WKA stock class flatheads. Now, that's with new flywheels that haven't been removed with a hammer and pry bars, dropped, chipped, lightened, etc. Handled correctly, they should be fine within the rpms that we have run stockers for years and years. It's when you go even beyond that you get in trouble.
They are statically balanced to the stock cast crank, an oem cast rod, and oem standard bore piston and ring set. The balancing is done primarily with a large straightline machining chunk removed from casting on the backside of the OD. Then add'l holes are drilled in the OD to balance it further. As soon as you change the rod (we all do) and piston/rings, the balance is lost. Then we advance the ignition timing and it's further lost. The balance was far from perfect when we began the build, it's only worse after the engine has been "built" for racing. Then we turn it twice the intended rpm. Balancing the crank or flywheel is not permitted in the stock classes. We've played with externally balancing them with the clutch and separate balancer wheel, but it's generally not needed or legal so no one pursues that anymore.
 
FlatheadsForever87 said:
All the years I have been at the track and in numerous flathead kart racers garages I have yet to see a single 5 hp billet flywheel. I'd like to have a few of those and the 3hp as well just cause they ain't rust magnets and I'm sure they are lighter. Who knows it may even save my life one day when I accidentally Rev my raptor over 20000 rpm. Lol. 20000 rpm is almost as likely as blowing a cast flywheel.
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either 3 or 5 adjustable or stationary check ARC
 
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