Flywheel bolts?!

[DX20VT]

Did you use Bill's method?? ie tighten down first, undo one at a time, locktite on the thread and oil on the head?? I can hardly see how you would get hydraulic lock unless you filled the whole thing with fluid, as the air inside would compress and push against the thread on the bolts, helping the tightening torque to keep the bolts locked in place.

It seems there was more to it than simply having loctite on there DX20VT... sorry but I would disagree with your mechanic as it just doesnt seem right from an engineering perspective.

no we did not do that, and it was a possibility that it was the cause, but not definatly the cause.

[o_man_ra23]

I still think you can rule out hydraulic lock, unless you had the engine with the flywheel up, and filled it with fluid first.

[wilbo666]

On some engines no locktite / sealing agent will cause u all manner of problems...

xJZ for example...you need to seal them as they are though into the crankcase...oil can leak past the threads and onto your clutch

Not ideal

Cheers
Wilbo

[rms]

Many years ago we had this happen with a specific make of race engine.

When fitted with a twin plate clutch, would shear flywheel bolts on the 4th/5th gearchange.

Single plate clutch...... never happened.

[DX20VT]

I still think you can rule out hydraulic lock, unless you had the engine with the flywheel up, and filled it with fluid first.

Not hyraulic lock with fluid,so say more compression lock, with air sealed in by the fluid,

But that's only a theroy too at the moment.

[o_man_ra23]

Nah, also impossible. The tightening torque of flywheel bolts far outweighs the amount of pressure you would get from airlock... air is quite compressable... and comes out of the loose threads pretty easy when you are threading in the bolts (even with copious loctite, it should still bubble through)

Plus the pressure from that air will push the bolts in the same direction as the torque from the threads, so it would just help, not hinder.

[Starfire]

They look like a simple case of mechanical failure to me. I would suggest that driving style, and the fact that you are making about 3x the power of the stock engine would have had something to do with it.

If I were you I would replace them with ARP or other similarly uprated items in future.

[takai]

To cross over from another thread, ARP bolts are around $45 or so for 8. They are shared with 4AG, and JZ series at the very least.

[DX20VT]

They look like a simple case of mechanical failure to me. I would suggest that driving style, and the fact that you are making about 3x the power of the stock engine would have had something to do with it.

If I were you I would replace them with ARP or other similarly uprated items in future.

Mechanical failuer is quite likely.

Cant be driving syle as I've only driven the car on and off the trailer once.
Was on the dyno when it happened, and was well past 3 X the power that a 7AFE crank was designed to handle.

ARP bolts are in my hand, and as there is only 6 on a FE crankshaft, we are looking at adding dowells in it aswell.

[merc-blue]

stock fywheel bolts making more than 3x factory power, thats brave

I have never had any of our engines have issues with flywheels,
EDIT, forgot had a ring gear fall off a flywheel in the middle of a race, combination harmonic issue and shotty work by previous owner (fywheel wasnt locked with grubs or a weld)
we use a similar method as bill. anything that is tight i always run a good tap and brush through to make sure the thread is clean and wire wheel the bolts,

1 clean all threads,
2 place on flywheel
3 lubricate heads (normaly use a very very small bit of moly)
4 tighten up to torque, pull on the flywheel square by tightening each bolt up abit at a time
5 one at a time remove a bolt loctite it and reinstal back up to torque


also make sure the mating surfaces are clean

[Starfire]

Wire wheels can damage threads. A better way to clean them is with a good solvent and or a thread chasing die if you have to.