[mechanickeith]

NO!! Dont loosen, just retorque to specs.

[track73]

Originally Posted by Steve Barcak

Such a catastrophic failure is very uncommon and needs to be studied. I've hurt a LOT of Pontiacs in my years but, never broke a cam in 3 peices.
How much oil was in the motor? Study this teardown carefully. Something is very wrong for this to happen just chugging down the hiway. Are you sure you were not running it hard? how much rpm? etc.


From the pics I could not see much block damage but it the cam is broke it is probably too far gone. Otherwise, you could sleeve it and save it.
Here is your pic of your head. I circled some things.


Hosting-
12th annual Pontiac Heaven March 26-28 Phoenix

You obviously didn't see my post about the catistophic failure of my 455 last fall.

[andyg]

Originally Posted by track73

You obviously didn't see my post about the catistophic failure of my 455 last fall.

Wow, that looks very similar to my pile of parts except that I didn't break any rods.

[trauschu]

I quizzed my local Pontiac engine guru who has been building race engines since the 60's about the scenario here. He said he has seen a few ponchos break the cam before, but it was "very difficult and rare". The few times he observed it, it was when someone forgot to install the eccentric on the front of the cam, and the cam walked around in the bore and caught another lobes lifter causing an immediate jam, cam failure, and then rod/piston damage due to cam pieces.

Just passing it on...

[screamingchief]

Originally Posted by trauschu

I quizzed my local Pontiac engine guru who has been building race engines since the 60's about the scenario here. He said he has seen a few ponchos break the cam before, but it was "very difficult and rare". The few times he observed it, it was when someone forgot to install the eccentric on the front of the cam, and the cam walked around in the bore and caught another lobes lifter causing an immediate jam, cam failure, and then rod/piston damage due to cam pieces.

Just passing it on...

Knowing your location and such,the guru must be Barney Moravits.

He does know his pontiacs,been building 'em for years.

His observation is pretty on point,could very well be a part of what happened here.



BP.

[trauschu]

Yep, good ole Barney!

[andyg]

The eccentric seemed to be on just fine when I removed it. It had gone those 2000 miles with no fuel issues ever, and I'm not one to be afraid to bury the go pedal.

I would be more inclined to believe the guess that maybe one of the lifters that came out jammed into the cam and shattered it.

Either way, the new engine runs great, but it sure is slow. That 170hp that is 33 years old is not as fun as the old engine.