Found out what went bad in driveline! Ouch

[Highlimit9000]

Scheered all of my flywheel bolts off! The holes in the Flywheel were elongated so I am assuming the bolts became loose until they finally broke
http://www.***boat.com/image_center/data/524/Flywheel.JPG
Front looks Good
http://www.***boat.com/image_center/data/524/Flywheel2.JPG
Busted the front piece of my spline drive also! Ouch! Can it be welded? Expensive piece! Any help out there?
http://www.***boat.com/image_center/data/524/Splinedrive1.JPG
Gonna do this type of set-up with a Billet Flywheel this time around. These are Aircraft rated bolts i got from a buddy in that business. They will all be safety wire tied and red thread locked. Thank god that flywheel didnt come off. The Spline drive held it in place without the bolts
http://www.***boat.com/image_center/data/524/Aircraftbolts.JPG

[Highlimit9000]

Glad Greg was on the water with his towing business that weekend! Just finished a pass in front of the Avi when it happend.

[Rexone]

Those bolts look to be Grade 5 by the markings. I would use ARP flywheel bolts and nothing else. But that's just me. :)
If the transmission wansn't tight on the block it might contribute to this also. You might want to check the front pump out. I'm just assuming you have a T400 application here.

[dossangers]

Like Mike said ARP'S red lock tight & FAAGEET'BOUT'IT:sqeyes: :sqeyes:

[Highlimit9000]

Those bolts look to be Grade 5 by the markings. I would use ARP flywheel bolts and nothing else. But that's just me. :)
If the transmission wansn't tight on the block it might contribute to this also. You might want to check the front pump out. I'm just assuming you have a T400 application here.
They were grade 8
The tranny was tight when I took it apart...
Interesting point on the ARP bolts. Some say not to use those 12 point wazoo 170,000 Psi whatever. They can be real brittle with scheer (Twisting) strength. Stretching wont find anything better...Couple different point of view out there....
Aircraft stuff is made to stretch more and not break...Designed not to come apart... Less brittle I guess...
Shouldnt have any problems with them loosening with the safety wire this time...

[obnoxious001]

I think Mike was talking about the gold bolts you show with the safety wire holes in them,, and only 3 marks on the head.
Red locktite and proper torque is critically important on driveline bolts.

[DUCKY]

I personally would use the highest strength bolts I could find (like the 12pt ARP's with red Loctite and maybe even some toothed washers). The ones in the pic with holes are not good enough IMO. On the spline drive welding, since it's just the pilot snout that is broken, I would get a competent welder to repair it. Just for info's sake, I have never seen one with a pilot snout on it before.....I am sure you could run it the way it is without fear.

[Highlimit9000]

I think Mike was talking about the gold bolts you show with the safety wire holes in them,, and only 3 marks on the head.
Red locktite and proper torque is critically important on driveline bolts.
Aircraft bolts do not have a rating like 5 or 8 ect...Those marks on these bolts are actually letters L S C its just hard to see them with that terrible pic....

[rrrr]

Looking at the broken bolts it appears that a few had broken long ago, look at the rust on the fractured surfaces.
I see two bolts that look like they have a fresh break on them.
But, it's a photo....maybe I'm seeing things.

[gn7]

your old bolts may have been grade 8 but those in the pic are grade five for sure. Your ould bolts were polly not shoulder fit to the flywheel and the slop let the flywheel rattle back and forth till the sheared. All the clamping force in the world can't stop this, the bolts have to fit snug in the flywheel. Also there is usually a dowel pin in the end of the crank and my money says you didn't have one, this helps also. AND LAST, I do not recommend saftey wire on anything that spins. Red loctite is all you need if every thing else is correct. Gett you self some real flywheel bolts (ARP) Also those bolts in the pic are airframe bolts, good stuff for bolting in you motor, trans, etc., they are damn near impossible to tear apart or break by bending, but they're soft and streach to easily andcan't clamp like a good ARP flywheel bolt. But then your buddy did say..............and it is your boat.

[Highlimit9000]

your old bolts may have been grade 8 but those in the pic are grade five for sure. Your ould bolts were polly not shoulder fit to the flywheel and the slop let the flywheel rattle back and forth till the sheared. All the clamping force in the world can't stop this, the bolts have to fit snug in the flywheel. Also there is usually a dowel pin in the end of the crank and my money says you didn't have one, this helps also. AND LAST, I do not recommend saftey wire on anything that spins. Red loctite is all you need if every thing else is correct. Gett you self some real flywheel bolts (ARP)
In the 1980's large numbers of counterfeit bolts appeared in the United States, almost all imports. For this reason, the SAE grade markings can no longer be trusted unless one knows exactly who made and graded the bolt.
A stronger bolt may not always be better. In some cases a bolt may be selected to fail at a certain stress to protect a more expensive part.
Bolts are graded, designating how "hard" they are. The "harder" bolt you choose, the higher the grade number, and the more brittle or "less shear resistant" it becomes. Higher grades are not necessairly better depending on the use.
The bolt material strength is determined by the alloy and processing method (for example, cold working and heat treating.)
The American Society for Testing Materials (ASTM) is one of the organizations which grades fastners in specification documents e.g. A193, A194, A320. Some equivalent grades are:

[superdave013]

They were grade 8
The tranny was tight when I took it apart...
Interesting point on the ARP bolts. Some say not to use those 12 point wazoo 170,000 Psi whatever. They can be real brittle with scheer (Twisting) strength. Stretching wont find anything better...Couple different point of view out there....
Aircraft stuff is made to stretch more and not break...Designed not to come apart... Less brittle I guess...
Shouldnt have any problems with them loosening with the safety wire this time...
The ARP flywheel bolts I've always seen are not the 12 point wazoo stainless deals. They are black oxide with the large 12 point head and proper shoulder for flywheels.

[Highlimit9000]

[QUOTE=rrrr;2692511]Looking at the broken bolts it appears that a few had broken long ago, look at the rust on the fractured surfaces.
I see two bolts that look like they have a fresh break on them.
But, it's a photo....maybe I'm seeing things.[/QUOTE
They were wet since they came out thats why...Including flywheel getting wet as you can see with the rust...

[dossangers]

The ARP flywheel bolts are only made for one purpose FLYWHEELS thats why they are the BEST!

[RitcheyRch]

Ditto that and would be the only thing I would use.
The ARP flywheel bolts are only made for one purpose FLYWHEELS thats why they are the BEST!

[Highlimit9000]

your old bolts may have been grade 8 but those in the pic are grade five for sure. Your ould bolts were polly not shoulder fit to the flywheel and the slop let the flywheel rattle back and forth till the sheared. All the clamping force in the world can't stop this, the bolts have to fit snug in the flywheel. Also there is usually a dowel pin in the end of the crank and my money says you didn't have one, this helps also. AND LAST, I do not recommend saftey wire on anything that spins. Red loctite is all you need if every thing else is correct. Gett you self some real flywheel bolts (ARP) Also those bolts in the pic are airframe bolts, good stuff for bolting in you motor, trans, etc., they are damn near impossible to tear apart or break by bending, but they're soft and streach to easily andcan't clamp like a good ARP flywheel bolt. But then your buddy did say..............and it is your boat.
Ok I will get ARP stuff with no wire. Any recomendations on the spline drive tip?

[Highlimit9000]

I personally would use the highest strength bolts I could find (like the 12pt ARP's with red Loctite and maybe even some toothed washers). The ones in the pic with holes are not good enough IMO. On the spline drive welding, since it's just the pilot snout that is broken, I would get a competent welder to repair it. Just for info's sake, I have never seen one with a pilot snout on it before.....I am sure you could run it the way it is without fear.
Any opinions on running it without the tip? I guess you wouldnt need a pilot bushing then either?

[superdave013]

Ok I will get ARP stuff with no wire. Any recomendations on the spline drive tip?
Just a quick thought. Find someone in your area with a lathe. Bore out the end and press a new tip (that was just made on said lathe) in there.

[DUCKY]

SD's idea is also a good one. Either way since it's there and you have the pilot bushing in the crank, I say fix it. I was just making a point that it's not 100% necessary to have the pilot snout.

[Moneypitt]

The pilot bearing/bushing's purpose is to support the tranny input shaft on the outer end. True, you have no clutch disc/pressure plate and the drive plate can't really move while bolted directly to the flywheel. IMO, the front tranny bearing would like to see some support on that end. What Dave suggested sounds good to me........MP