any reason NOT to use an alum flywheel on my 5hp IC??

[125ccCrazy]

I have an alum flywheel (stock briggs part) that was on a built 5hp kart engine that I bought, well the eng turned out to be junk so I bught an IC 5hp and plan on building that one up.. I was gonna use the alum flywheel but was told they blow apart?? any truth to that?? I was told to use a 3hp steel instead..... I looked at billet but they are dang near $200, twice what my 6.5 clone billet cost...

I can't see how it will blow apart, it was on this eng for years judging on the engine and I know the kid beat it relentlessly...

 

[5 Horse Fan]

Basically, The Aluminum Flywheels made from Briggs & Stratton for 3hp flatheads are Cast Aluminum.

They were designed to rotate at a maximum of 4,000 RPMs (Factory Governed)
Rumor has it, they explode after repeatedly exceeding those RPMs.
I myself have seen photos of exploding Flywheels, but they were from very large flatheads, like 12HPs.

Billet Aluminum Flywheels have been tested to exceed 9,000 to 10,000 RPMs depending on the manufacturer.

Actually, every factory made part of a Briggs 5hp was designed to rotate under 6,000 RPMs.

The Raptor 1, 2, & 3 Engines were designed to rotate faster, but they still expirienced engine failure due to Cast Aluminum Connecting Rods. Later on,Billet Connecting Rods were available as after market performance parts.:thumbsup:

 

[Jay Wrix]

yes, they will explode, and its like a bomb going off.

ARC just lowered the price of one of the flatty billet flywheels

#6620 Billet Flywheel for 100 dollars, contact ARC racing
you would have to use some type of key....

The guys at ARC are really helpful, and Id call them and see what they say

But as for aluminum, big NO-NO

 

[125ccCrazy]

Thanks guys for the replys.... I looked up arc but they only show teo flywheels, one for a Briggs V twin ($350) and the other for the 6.5 honda clone and BSP clone, whatever a BSP clone is... That one is $100, I didn't see anything for a flathead 5hp Briggs... The cheapest I've found for a flywheel is $169 on ebay..:doah:

 

[812 Motorsports]

Just use the stock steel flywheel, its safe up to 6000rpm

 

[Jay Wrix]

Like I said, you have to call them for the flathead flywheels,

I hate to say it but the flatheads dieing,

ARC recently redid its website and theyre still missing alot of stuff

Just give them a call, and ask for Flathead flywheels
Tell them your running gas, and youll need a key for the timining
(you have to -RETARD- the timinging, not advance, its set for alchohol)

Its really simple, But the stock iron flywheel is good till 6,000

a BSP clone

Is the "box stock project"

Generic honda clone motor

 

[bandit 40]

ARC Flywheels are now SFI Certified!
« on: October 30, 2005, 11:33:01 am »

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Post by Tom on Aug 11, 2005, 11:46am

Exciting news from ARC Racing! We have had each of our billet flywheel designs tested and certified by the SFI Foundation!

ARC billet flywheels are the only flywheels available for 4 cycle Karting, Jr. Dragracing, and Lawnmower Racing that are approved by the SFI Foundation, a nationally recognized racing industry saftey standards organization.


Previously purchased flywheels ARE NOT automatically certified. But, we are working out a plan where our customers can send their flywheels to us to be inspected and certified IF certification should become a requirement of their respective sanctioning body. This will be very inexpensive.

The whole purpose of this is to eliminate assumptions that a billet flywheel, or any flywheel for that matter, will last forever. There are tremendous forces working on a flywheel during use. Fatigue over time, damage from impact with debris, or mis-handling during installation and/or removal can create saftey related issues that require the flywheel to be retired at some point. Although we have not had any injuries associated with our flywheels, we felt it was prudent to take steps to maintain

 

[JustEnough]

If you register at 4cycle.com, you can then use the search function to search the Free Classifieds section for the word flywheel. I found a "ARC Billet Adjustable Flywheel (Flat Head)" for $75, that looks promising. The sellers name is Dirt-Poor.

I found a good thread on flywheel safety in - Cycle Karting Forums > Categories > Flatheads Forever > General Flathead using the search words - stock flywheels bombs.

The last post of the thread titled "stock flywheels time bombs? how much do they take?" put things into perspective for me:

"...the guy was twisting the guts out of a limited sitting on the test stand,they stopped the racing so we all could look for his fingers,never found them as best i remember,but that was the last time my son went to the track w/me..."

 

[Jay Wrix]

I saw a picture were an 18HP Vanguard flywheel exploded, and destroyed the tractor, put a gouge in a large I beam and went through the wall of the pole barn,

In other words, Try not to mess with flywheels too much, and use whats tried and true

 

[125ccCrazy]

If you register at 4cycle.com, you can then use the search function to search the Free Classifieds section for the word flywheel. I found a "ARC Billet Adjustable Flywheel (Flat Head)" for $75, that looks promising. The sellers name is Dirt-Poor.

I found a good thread on flywheel safety in - Cycle Karting Forums > Categories > Flatheads Forever > General Flathead using the search words - stock flywheels bombs.

The last post of the thread titled "stock flywheels time bombs? how much do they take?" put things into perspective for me:

"...the guy was twisting the guts out of a limited sitting on the test stand,they stopped the racing so we all could look for his fingers,never found them as best i remember,but that was the last time my son went to the track w/me..."

I tried that guy, he either doesnt want to sell his stuff or something as he doesnt reply back. he has the flywheel, a head and side cover I want but he's fluffin me off... I'll find one sooner or later...

 

[Strigoi]

I saw a picture were an 18HP Vanguard flywheel exploded, and destroyed the tractor, put a gouge in a large I beam and went through the wall of the pole barn,

In other words, Try not to mess with flywheels too much, and use whats tried and true

do you remember what thread that was (i know i saw it posted here)?

i've looked for it many times with no luck. i really wished i bookmarked it when i read it. that should be enough to convince anyone running without a governor to go with a billet rod and flywheel.

 

[Jay Wrix]

do you remember what thread that was (i know i saw it posted here)?

i've looked for it many times with no luck. i really wished i bookmarked it when i read it. that should be enough to convince anyone running without a governor to go with a billet rod and flywheel.

uhm, I saw it on 4cycle, (I think) I could look for it

It was really interesting to see the force that they explode at, and it showed me I didn't wanna be anywhere near it...

 

[minidragbike]

I have a billet adjustable 3hp ARC flaywheel with finns for $125 shipped if you want it.

 

[5hpminitech]

i,m pretty sure arc just lowered the price on non adjustable flywheels to like only 100 you can use like 2.00 dollar keys to adjust the timing or lap the flywheel with no key call arc the flywheels are cheep know its worth it

 

[minidragbike]

Not the adjustable ones, they are still a little pricey.
Also if you do plan to lap the flywheel on, that DOES NOT MAKE IT STAY IN PLACE. It only makes the both contacting areas contact better, or mate better. It will still need to be impact on with a impact gun. You will also need to check your timing after doing this, because the flywheel could move before it actually starts to tighten up. I just use a key to keep it in place, then impact it on. That way you don't have to worry about slipage.