My Camaro went home to Oshawa to die......

[Huggerorange73]

Originally Posted by PAUL SS

Then its chicken and egg time, did the mark on the bolt happen when it was torqued or when the pin broke? If it happened when it was torqued (which I am leaning to) then there was insufficient clamping force on the gear forcing the pin to bear more stress than it was designed for.

This is going to be the tough part to prove....but it's THE key part.

[GTAHVIT]

If that pin was extending that far, they would have seen the proper torque, but the bolt was no where near seated with the proper torque... Think about how little rotation is needed to increase the torque amount on a bolt. even a mm too long of a pin would significantly reduce the clamping force of the bolt.

IMVHO.

[PAUL SS]

Does the pin come already installed on the cam or does it have to be installed by the customer?

[garcmol]

Originally Posted by GTAHVIT

If that pin was extending that far, they would have seen the proper torque, but the bolt was no where near seated with the proper torque... Think aobut how little rotation is needed to increase the torque ammount on a bolt. even a mm too long of a pin would significantly reduce the clamping force of the bolt.

IMVHO.

Exactly what I'm saying. May have been torqued right to spec + X degrees, but it was torqued against that pin.

[PAUL SS]

Originally Posted by GTAHVIT

If that pin was extending that far, they would have seen the proper torque, but the bolt was no where near seated with the proper torque... Think about how little rotation is needed to increase the torque amount on a bolt. even a mm too long of a pin would significantly reduce the clamping force of the bolt.

IMVHO.

And if it was torque plus degrees and the degrees was 180, there's your mark on the bolt!

[skip_168]

So whats the consensus now? pin breakage is the cause or the effect of the engine failure?

[PAUL SS]

Originally Posted by skip_168

So whats the consensus now? pin breakage is the cause or the effect of the engine failure?

Effect. Improper torque due to too long a pin. Not a consensus, just my theory.

[skip_168]

how many cylinders/valves were damaged? I assume that once the pin gave way the cam stopped & the crank kept going & whacked a few cylinders' valves?

[Huggerorange73]

Originally Posted by PAUL SS

Does the pin come already installed on the cam or does it have to be installed by the customer?

Pin is in the cam already, Comp says it's on the installer to insure the pin is the proper depth for the application.

Originally Posted by PAUL SS

And if it was torque plus degrees and the degrees was 180, there's your mark on the bolt!

From what I'm reading the spec 55 ft lbs plus 50 degrees.

[Huggerorange73]

Originally Posted by skip_168

how many cylinders/valves were damaged? I assume that once the pin gave way the cam stopped & the crank kept going & whacked a few cylinders' valves?

The entire engine was destroyed....# 1 rod shattered, piston and rod parts went through the block & oil pan. # 7 has no piston left...connecting rod & wrist pin are still intact.

Exhaust valves broken off on # 1, 2 & 7. Multiple other valves bent, pushrods bent...# 2 exhaust lifter went through the block.

[PAUL SS]

Is it possible the pin could appear flush with the gear face, but extend past the gear face as the bolt it torqued down?

I'll shut up now.









/

[HumanWiki]

Originally Posted by Huggerorange73

The entire engine was destroyed....# 1 rod shattered, piston and rod parts went through the block & oil pan. # 7 has no piston left...connecting rod & wrist pin are still intact.

Exhaust valves broken off on # 1, 2 & 7. Multiple other valves bent, pushrods bent...# 2 exhaust lifter went through the block.

Well, if the tech thing doesn't work out -- maybe GM will get you a job in their real-world simulation testing labs or something... If it survives you and Dan -- and some of the other members on here, it should be pretty solid.

You guys don't just break a car.. You create chaotic art..

[skip_168]

Originally Posted by Huggerorange73

The entire engine was destroyed....# 1 rod shattered, piston and rod parts went through the block & oil pan. # 7 has no piston left...connecting rod & wrist pin are still intact.

Exhaust valves broken off on # 1, 2 & 7. Multiple other valves bent, pushrods bent...# 2 exhaust lifter went through the block.

nice! full on grenade... Thanks for the summary, 500 posts of would have made me ...

I thought it was just a over-rev or interference strike before...

[skip_168]

Originally Posted by PAUL SS

Is it possible the pin could appear flush with the gear face, but extend past the gear face as the bolt it torqued down?

I'll shut up now.

/

back in my engine building days, those cam pins were recessed about .020 to .030 to allow for gear compression, but I have to be honest, I never even gave them a second look on $50,000 engines... glad I didn't screw up...