Toyspeed.org.nz Message Board

by **matt dunn** » Mon Oct 06, 2008 10:21 pm

How does this happen?

??????????????????????

by **bluemaumau** » Mon Oct 06, 2008 10:28 pm

by **evlnxr** » Mon Oct 06, 2008 10:30 pm

Ouch dude. Lucky the rest held together and didnt fly out thru the bellhousing.

Looks like a castiron unit? Prob just fatigue / wear and tear. Was it running a stock pressure plate or resprung / Heavy duty?

A heavy duty clutch pushes pretty hard on that part of the flywheel, so its not an unusual place for it to break.

If you can afford it, go to Precision Engineering in Albany Aucks and get a billet one made. Most are usually around the $500 mark with the ring gear machined out of the same billet. i would rate them as far superior to a Jun one, but thats only compared to the S15 turbo one i had, the Jun one was a piss poor design.

by **Boosted_162** » Mon Oct 06, 2008 10:30 pm

Damn.

This isnt the first time you've had problems with flywheel bolts is it?

by **matt dunn** » Mon Oct 06, 2008 10:33 pm

Boosted_162 wrote:Damn.

This isnt the first time you've had problems with flywheel bolts is it?

No, but as you will notice, the flywheel bolts and extra dowell's are still in there fine.

was a standard unlightened, un modified 4AFE flywheel,
apart from the two extra dowells,
but there are no cracks leading to or away from the dowells,
so dont think that weakened it.

Will post the incar on youtube later of when it happened.

by **l1ttle_d3vil** » Mon Oct 06, 2008 10:35 pm

your car is too fast, turn your boost down.
or possibly an "incompatible engine" :lol:

but seriously, thats scary

-+=gon-zo-crazy=+- · by **neo** » Mon Oct 06, 2008 10:39 pm

damn,,,

Guess youve found what the threshold of a 4AFE flywheel is

by **postfach** » Mon Oct 06, 2008 10:43 pm

l1ttle_d3vil wrote:your car is too fast, turn your boost down.
or possibly an "incompatible engine"

but seriously, thats scary

I want to know how it was an rx7 motor for a mazda 3???

That flywheel is nuts Matt, what was it like when it happened?

by **4agtepwr** » Mon Oct 06, 2008 10:59 pm

Holly shit Matt! thats pretty unreal im a little spechless.

by **crispy'86** » Mon Oct 06, 2008 11:01 pm

That's just damn scary!!! You'd almost think the flywheel is too thin from factory where it bolts to the crank. All that torque going through the flywheel obviously can't be good for it!!!!!!. Time for a stronger unit Matt?

Website · by **Bling** » Mon Oct 06, 2008 11:03 pm

i'll take a stab at too many rpm and shes given up :lol:

by **matt dunn** » Mon Oct 06, 2008 11:19 pm

BZG|Bling wrote:i'll take a stab at too many rpm and shes given up

Limiter is only around the 8500rpm mark, and I dont run on the limiter, (anymore)

by **Bazda** » Mon Oct 06, 2008 11:28 pm

I didnt have my standard flywheel on for long enough to find this out. All my car did was clutch slip so just went to a twin plate with custom billet flywheel.

The flywheel is acutally cheap to make if you supply the std ring gear.
Think my flywheel was under $300.

Also when you down shift do you rev match... and just drop it into gear and let your foot off.. I would also say that can give the flywheel and clutch a hard time.

by **KinLoud** » Tue Oct 07, 2008 7:30 am

I have a couple of thoughts on this...

- on a standard flywheel, are all transitions between flat and curved surfaces (cast vs machined surfaces) radiused correctly? Any sharp transition would create a stress raiser that would help to start a crack.

- work out how many races the flywheel did and just "life" your flywheels and 2/3s of this number of races?

Ken
Auck
021 408 863

by **fangsport** » Tue Oct 07, 2008 8:17 am

nasty stuff there Mat.
out of curiosity, do you run the 2 brackets from bottom of the block, to the lower section of bellhousing?

by **Mr Revhead** » Tue Oct 07, 2008 9:54 am

i would say its more likely to be flexing from the HD clutch than out and out power twisting it apart.
maybe a combo of the two, the HD clutch flexing it weaking it

by **Adamal** » Tue Oct 07, 2008 10:05 am

20 tonne pressure plate

by **Voyeur** » Tue Oct 07, 2008 11:55 am

My experience is with tractors not cars, but i have seen this before.
Excessive slipping of a metallic clutch (flywheel gets too hot)
Solid centre metallic clutch (excessive drive train shock)
Worn crankshaft thrust bearings (not really a cause, more a result)
Incorectly machined flywheel surface, stepped flywheel

by **matt dunn** » Tue Oct 07, 2008 1:07 pm

Bazda wrote:I didnt have my standard flywheel on for long enough to find this out. All my car did was clutch slip so just went to a twin plate with custom billet flywheel.

The flywheel is acutally cheap to make if you supply the std ring gear.
Think my flywheel was under $300.

Who are the people to see about getting a billet flywheel made?
cant buy them off the shelf with the 6 bolt pattern.

by **85AW20v** » Tue Oct 07, 2008 1:36 pm

Haven't played with rear drive before but is it usual for the spigot bearing to come out with the g/box or should it stay with the crank? Possibly a cracked crankshaft somewhere near the back end caused a vibration that broke the flywheel? Just a thought.....

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