Check your lower pulley bolt.....Pics

[serickson1]

Found out the hard way this should be part of our yearly maintenance if you are running high boost levels and aftermarket lowers. This is not a negative thread against ATI.....they make excellent race proven lowers and I have already ordered another 10% lower for my new motor build along with an ARP harmonic balancer bolt. Never thought to check the new factory torque to yield bolt I installed with the new balancer......it appears the bolt backed out a little and caused the failure. Unfortunately the damage to the crank was on the backside of the seal sending metal shavings into the motor and ruining the crank snout.....
This is not a thread to bash ATI or start a ATI vs IW debate so do not go there and I will not be responding to any questions or comments that try and go that way.....my bolt backed out....I didn't check it....results below....
Build in progress.....built motor with 4.2KB, E-85, JDM cams, and Lund tune.

 

[12gt500]

Did you use a new bolt?

 

[serickson1]

Yes....factory torque to yield bolt.

 

[spitin venom]

That sucks big time! You will come back bigger and better.

Did you use loctite?

 

[TORQJNKY]

serickson, I thought the aftermarket dampeners used a longer than bolt, M12 x 1.5 x 100MM instead of the OEM M12 x 1.5 x 85MM? I know they recommend a longer bolt to help press the pulley on but it only makes sense that if you can't use the shorter stock bolt to press it on the pulley must be slightly thicker than stock...just guessing. Just wondering if you had enough thread engagement in the snout. Loctite?

 

[Catmonkey]

serickson, I thought the aftermarket dampeners used a longer than bolt, M12 x 1.5 x 100MM instead of the OEM M12 x 1.5 x 85MM?

This is correct, but the ARP balancer bolt is only 45mm in length. APR does package bolts of all sizes. I thought about ordering a set of bolts of the right dimension, but just went back to the stock TTY. The problem with TTY bolts is you can't really check them for tightness. You risk over stretching the bolt and reducing the clamping force.

I see ARP now offers a bolt for the 5.0, that is the right thread and pitch, but it's 106 mm, so it might be too long.

 

[lawdude]

ARP2000 bolt is holding my custom IW balancer on.

 

[12gt500]

Yes....factory torque to yield bolt.

man this sucks i am just starting a engine build with the 10% ati. i got a new ford bolt from van with purchase. should i use another bolt or is there any other precautions i can take to avoid this.

 

[NickSezz]

We use a new stock bolt as well and have no failures to date.

 

[12gt500]

We use a new stock bolt as well and have no failures to date.

So I should be safe? I am going to be running about 24lbs of boost on a kb 3.6 built sb

 

[nxhappy]

did you use Loctite OP ?

 

[upnorthguy]

What should a guy torque (foot pounds) the new factory bolt to I just put a 15% ATI on?

 

[19COBRA93]

What should a guy torque (foot pounds) the new factory bolt to I just put a 15% ATI on?

The factory bolt needs to be torqued to the factory settings.

Which should be;

Using the factory crank bolt:
Torque to 88 ft lbs
Loosen one full turn
Torque to 37 ft lbs
Turn additonal 90 degrees

As for ARP, they don't make one specifically for the GT500 5.4L. But, ARP part number 674-1010 is a perfect fit. They come in a pack of 5, and are inexpensive (and you get 4 extras!). They're 8740 chromoly, and the size is M12 X 1.50 X 90mm. The clamping force with this bolt is substantially more than the OEM TTY bolt. The tighter the bolt, the less load there is on the snout/keyway. I'm running this bolt (with an ARP washer) in my crank with my 4.0L.

Even with a double keyed crank, you still need a tight clamping force to transfer that energy away from the end of the snout and towards the main journal of the crank.


As for the OP, that sucks. But, IMO, a properly torqued OEM crank bolt will never come loose on it's own. I don't think your bolt backed out, I think there just wasn't/isn't enough clamping force with the OEM bolt when run with a big supercharger. It places too much load on the key/keyway.

 

[serickson1]

I don't believe we used loctite....

 

[19COBRA93]

I don't believe we used loctite....

You don't need to. A properly torqued bolt will not back out. Period.

 

[nxhappy]

Loctite could have saved you bro ....

 

[19COBRA93]

Loctite could have saved you bro ....

No it wouldn't have. It's absolutely unnecessary to use locktite on a properly torqued crank bolt.

 

[serickson1]

We did the three step procedure per Ford.....no loctite is specified by Ford nor was it present on the original bolt from the factory.

 

[TORQJNKY]

As for ARP, they don't make one specifically for the GT500 5.4L. But, ARP part number 674-1010 is a perfect fit. They come in a pack of 5, and are inexpensive (and you get 4 extras!). They're 8740 chromoly, and the size is M12 X 1.50 X 90mm. The clamping force with this bolt is substantially more than the OEM TTY bolt. The tighter the bolt, the less load there is on the snout/keyway. I'm running this bolt (with an ARP washer) in my crank with my 4.0L.

Do you want to part with one of those (4) extra bolts? :thumbsup: