Cause: ARP 8740 rod bolt failure on #5. One sheared, the other one pealed over from cap deflection.
This was not a journal or bearing problem, the journal is clean. Lower half of rod #5 is lodged in #4.
Apparently the web is full of identical experiences with ARP rod bolt failures. As you all might imagine I am pretty well upset with ARP.
There is not one single salvageable part remaining of the short block.

Man, I feel bad for you, That really sucks. Probably no chance of them covering anything as far as parts.

Hope something good happens for you

Boosted

ARP is having problems failing out? Man, and they are supposed to be the best! My condolences, hopefully you can get them to make it good.

If they tested the bolts and found a defect (there HAS TO BE) they simply provide another set, which I would not want, not even to give to someone I hated.
The only way to qualify a rod bolt during assembly is measuring stretch while torquing. I don't have the abaility to do both at the same time, I just used stretch. My torque wrench is just a conventional 1/2 drive ratchet sort, so can't do both.
As the process goes, both torque and stretch should land within a range of acceptible numbers. If it doesn't, $4 bolt gets thrown away.

What it comes down to is that even parts traditionally trusted have to be treated as if deffective out of the box. F'ing sucks. Badly.

That blows hard. Nothing is salvagable? you said it didnt nick the crank arent any of the other rods or pistons ok? Where they rod bolts or rod studs? How the heck would someone even measure bolt stretch and torqe at the same time or without the bolt actually out?

i just died a little.........

Man I hate to hear that. That really sucks especially when the
Motor didn't even have the whipple on it yet and was rated for WAY more power than
Was run through it during break in.
Do you have any pictures of the bolt failure?
What is wrong with the crank?

That's....
So sorry to hear this.

Hmmm What would John Force and Team Castrol do if they lost a big race to a rod bolt snapping.... I think they'd eat ARP for lunch..... Clearly theres two classes of product....

Now I know why I wore black today...

TJ

If there is a set of bolts that actually WORKS, I don't care what they cost.
BTW, it quit at 1900 RPM with the cruise control on. That's why there was no collateral damage to anything else in the engine compartment, not even the Knock sensor wiring right there in that area.

I'm almost wondering that there was too little clearance in the bearings causing poor oiling flow causing the lifters to make noise. The bearing clearnance being too tight is what could have been from the bolts being torqued down due to the bearings not fitting properly and allowing too much stress on the bolts.... If there wasn't enough oiling in the bearings and they started sieze the torque from the motor could have been what caused the bolts to shear rather than plainly spin the bearings. Was it really due to the bolts, or did they fail due to some other reason revolving around the oiling issues you stated from the getgo? I'm probably just pissing in the wind but I'm interested to learn something here.
TJ

My guess is that it snapped from the stress of knowing what you had planed for them. The anxiety buildup was just too much...


So with the cap cracked open but still held in place by one bolt, the oil pressure pulsated from the journal oil hole being more or less covered by the connecting rod bearing with each revolution.

Checking rod stretch.

http://www.youtube.com/watch?v=1ys0YKKqXbU

Something like that is locical as well... Something happened during the torque down process causing the caps to be loose and so at low RPM's there wasnt the pressure/volume build up there by causing the lifter noise. At the higher RPM's there was enough oil volume to compensate that quieted the lifters for a while....

I think the lifters were noisy through no fault of their own and became the smoking gun....

As much good press as ARP gets, I think there is something else at the root of this besides them just snapping. Possibly send them to a metalurgical lab and have them tested to rule that part out.

TJ

98Blackss wrote:

....Possibly send them to a metalurgical lab and have them tested to rule that part out....

Yep... I am building a pallet of scrap metal, the rod fasteners are being kept for analysis.

Holy cow! Cool video, I didnt realize that bolts streched that much, or at all unless they were over torqued. I learned something so it was a good day!

Now where to get one of those fancy tools! because I generally put my strength and weight into the wrench when tightening stuff down. There really is a limit. Now I do have a torque wrench when I'm working on my vehicles and always look up the values. It goes to show how important it is for the TQ wrench to be accurate!!!!


TJ

The problem with that method is that it will not catch a defective fastener. Both torque and stretch have to land in-spec in order to qualify as a "good" fastener. Torque specs for rod bolts will specify the type of lube to use. In my case I was instructed to use straight 30wt oil, which I did. A bolt may come up to torque without stretching enough which means the fastener is too hard and will be brittle and thus prone to snapping. If it stretches too much reaching the torque spec the material's tensile strength will be compromised and clamping ability reduced.

Is there even such a tool as an open end torque wrench, so you can do both? I know you mentioned something to the effect earlier on. I have your run of the mill crapsman 3/8 and 1/2 socket TQ wrench as well. Hey an excuse for a new tool!!!

TJ

98Blackss wrote:

Now where to get one of those fancy tools! because I generally put my strength and weight into the wrench when tightening stuff down. There really is a limit. Now I do have a torque wrench when I'm working on my vehicles and always look up the values. It goes to show how important it is for the TQ wrench to be accurate!!!!


TJ

Bad vid but interesting vid for industrial pluming flange fasteners.

http://www.youtube.com/watch?v=a4RXNV6DJFI

James, I don't understand why you need to read both specs at the same time. Why couldn't you just measure the bolt, torque to spec, then mesure the stretch.

I love ARP ultra torque lube. Better than oil.