Ever so recently I've dropped in a AWD 6-puck ACT clutch kit. It's unsprung so it's very harsh with engagement. Anyway, here's the story. About a month ago, I was a kilometer away from home when my clutch desided it didn't want to work anymore.

I pushed it home with a couple guys and took the transmission off. Low and behold 3 out of 6 flywheel bolts were SHEARED off right at the heads.

I took them out, replaced them torquing them down in a star pattern progressively all the way up to the torque spec 10Xlbs-ft from what I remember and threw everything back together.

Fast forward to this past Wednesday night at Cayuga. I'm blasting down the track, tuning the car just right, doing a forth gear pull. When all of a sudden I feel my engine and my transmission disengaging. I pull of to the side of the slip booth and get it towed home.

After about 18 beers between 2 guys, we take the whole motor out, take off the transmission and clutch assembly. DAMN FLYWHEEL BOLT! One of the bolts is sheared right off AGAIN. It caused my clutch disk to ram itself into the TOB sleave and cause damage there too.

Can anyone suggest ANYTHING to help me out here.
I'm going to start by buying 6 BRAND new bolts. Any other suggestions. I might even pick up a street disk rather then this puck chatter. Pictures are coming.

I've heard talk of people using ARP flywheel bolts, which I would think would be significantly stronger.

Not sure about the details though.

Just remember on the ARP bolts they are a little longer so you may have to bottom tap the threads on the crankshaft.

I am not sure what sort of clutch you have but the stock bolts aren't that bad. I had never heard of this really.


the flywheel doesn't happen to be off an automatic car!?!


and also how much torque do you put on it in Foot.Pounds?

making me nervous here.....I reused my flywheel bolts. Has anyone else had this problem?

When I rebuilt my motor on '03 the flywheel bolts were reused, 15K no problem's. When I did it again this year they were new bolt's.
Torque is 90-110ft lbs I believe with loctite.
Auto's don't have flywheels that would work at all with a manual tranny.

Something is making these Bolts snap.

The Crankshaft should have a Dowl... Did you happend to notice if it had one???

Ghislain.

The flywheel has the dowel in it actually. I'm going to put it into the crank first this time then hopefully it'll slide onto the flywheel. I never used loctite so possibly I'll give the red a try.

Heres what baffles me. The bolt sheared off right where the flywheel meets the crank. So when I pulled the flywheel off, the remainder of the bolt was still threaded into the threads flush with the crank.

What seemed to have happened is the bolt head lodged itself against one of the 6-puck rivots and acted as a jamming devise. I have a new 6-puck on it's way now though.

LAST time this happened. (which was not so long ago). Two bolts were sheared off right from the head and two were sheared off right where the flywheel meets the crank. I HATE to have this happen again but there is no way I will ever put an ACT street disk in my car. Those things pop springs like no other. That's catastrophic.

Tim, two things:
1. It is highly possible that your flywheel is way out of balance. I suggest you replace it.

2. Also, since you are using an unsprung six- puck clutch, nothing is absorbing the tremendous amount of impact during engagement. Something has to suffer...in this case your flywheel bolts.

Unsprung clutches are overkill for street use. If you checked the literature that came with your clutch, there's a part that says, "flywheel must be inspected regularly with the use of this clutch". Unfortunately this is not easily done on a street driven car.

Good luck

I have never heard of this even with guys running act 2900 or triple or dual disc setups.
These same guys are running over 600 crank hp.

Hope flywheel is out of balence... thats seems only logical thing, OR that there is a manufacturing defect in your clutch.

It sounds like the flywheel is spinning relative to the crankshaft if the bolts are shearing at that joint. If there is supposed to be a dowel between the two, you can't have it properly engaged, or you would have had to shear the dowel also!!

Still on the stock flywheel Tim?

Still stock. I'm going to try to purchase a sprung clutch kit (6-puck, organic, etc).

I am with Ziggy on that one.


I asked if the flywheel is off an Auto. I meant the crankshaft.

because the autos have a little insert that doesn't let the flywheel sit against the crank.


What seems to happen here is that the flywheel is not having enough friction against the crank end.

Mecha Eng. Lesson 1.1 is that Bolts are NEVER FOR SHEER(atleast in their bolt form).

What a bolt is supposed to do is to clamp the two objects and then the surfases should have enough friction to do that job. if you look at specs of an average bolt the tensile strength is 70000PSI but sheer is a fraction of that.

in this case what is likely is that the crank and flywheel are not meeting properly or the surface is not right.

I would look at both surfaces for any visual "irregularities".

then I would clean them off from ANY SORT of grease, what them with brake cleaner and sand paper even.

make sure the flywheel goes to the end and meets the crankshaft end.


and make sure the dowel pin is there and it is tight in the crank AND the flywheel. I really don't think that dowel pin is supposed to do anything other than alignment, but in a stretch of the original design like this clutch you ar e runnning, anything helps.


if you have some means of checking check end of the crank and inside that sitting surface of the flyweehl for flatness.

It might easily be that the dowel was intended for alignment only, but it WOULD definitely add CONSIDERABLE shear strength as well. Amin is correct about shear strenght of a bolt being a small fraction of it's tensile strength, but the shear strength of a dowel is probably the equivalent of SEVERAL bolts. It could easily be that the problem is unclean surfaces, but it still seems to me that if the dowel had been properly installed, it would have been IMPOSSIBLE to shear the bolts without also shearing the dowel....and I doubt very much that is happening!

Ziggy is 100% correct. Something else is wrong. If the flywheel was sitting flush with the crank and the dowel was in, sheering would be nearly imposible unless your dowel and dowel holes are all fubared up. They should be a .0005" clearance fit together. The only thing that would have broke your bolts is if they came loose letting the dowel fall out of one of the mating surfaces, or lateral movement in the flywheel of some sort causing them to be pulled apart rather than sheered.

Actually Amin, it originally did come off of an automatic car. I have a turbo manual block here and will be heading outside to figure out differences between the blocks.

Rob, the 6-puck unprung disk is violent though. I've been in sprung 3 puck cars before, this is just way too crazy. I'm either going SBR 3500 or an RPS Stage 3.

dude,

make sure that little insert for auto cars is out of there. it makes end of the crank not flush.

it goes inside the crank hole and doesn't let the flywheel to sit in properly.

and I know that Auto cranks don't have the dowel pin(my car doesn't). you said you got that put in?


Tim,
I really have to bolt your ass to the wall if you forgot that piece in there and never noticed the flywheel not sitting properly!

The dowel pin hole IS there. I remember when I took the flex plate off, there was a spacer that basically fell off right away.

[img]http://www.dsmtuners.com/forums/attachment.php?attachmentid=55166&stc=1[/img] [img]http://www.dsmtuners.com/forums/attachment.php?attachmentid=55164&stc=1[/img]

****, is THAT it there?

WTF Tim!!!

I see the problem right away.

This Engine/Crank is from an AT. MT Crank do not have that Sleeve.

Pull that thing out and slap everything back together and install a new Dowel.

That should also take care of the harsh engagement.

Ghislain.

That centre "ring" that is in the crank needs to be removed.
Your flywheel is not sitting tight on the crank and this is why you are breaking bolts.
That ring will come out, it is a press fit into there.
[img]http://www.dsmtuners.com/forums/attachment.php?attachmentid=38064&stc=1[/img]
Link if pic does not pop up.

That ring is there for aligning on auto car's and need's to be removed on an MT.
New flywheel bolt's and you should be OK with whatever clutch or PP you use.

Alright, I'm officially stupid. Everyone, call me an idiot and let's close this thread.

Is that center ring the "AT spacer" (MD952138) I read about people using in conjunction with the ARP flywheel bolts (to avoid tapping the crank?).

No the AT spacer is a thinner metal plate that goes on the outside of the flywheel, rather than in between the flywheel and the crank
Think big washer with 6 holes in it.
It also allows you to really torque down the bolts without galling up the face of the flywheel.

That makes alot more sense!

Thanks Tim!

Tim?
wtf man?!


did you get it out?
I remember when I was helping Darko put his car back together we had that problem but with AWD tranny you cant get it in. Later Nick boers and a few other guys found that there and they used a socket and grease to get it out.

Socket and grease?

Now I realize why it was soo hard to get the tranny in the engine bay when I replaced the bolts the first time. The flywheel was out an extra inch.

Explain the grease and socket trick.

Just remember this as a precious moment Tim.

Something to tell your grandsons when you are old and getting ready to really lose it.

Keep at it!!!

Wiseman Giz.

HA HA (laughs like Nelson)

On the internets, we laugh at you as follows:

At least I learned a few things from Tim's mistake. There should be more threads like this one!

HTF do I get this spacer out? It's REALLY in there.

BUDDY, if I made a post like this for all the problems I've had, which have been dummy mistakes like this, I'd have my own forum.

****ty when something simple like that is the problem...
Pretty sure the socket and grease trick is... Find a socket that fits snuggly in the bore, use a bolt and washer through it to plug the hole it the socket and fill the bottom of the crank with grease. Then put the socket in and hammer away. The hydrolic effect of the grease should push out the sleve.

Matt

Air Hammer and Chisel.

Ghislain.

Tim,

do what Matt said. the idea is to find a "piston" for the hole you have there, then fill it with grease and bang the piston, being the right size socket. so when the piston goes in it pushes the grease out and as the grease is trying to squeeze its way out it pushes the ring out.

Does anyone have anything similar to this but possibly with larger hooks?

Heat it with a torch relitively hot but not glowing, then cool it fast and that should break it free. Or you could do it my personal favourite way and beat the living f*ck out of it like it owes you money. Just dont damage the crank.

Heat it up, then try a pair of visegrips on it.