What would cause the cam to go flat on the #4 cylinder exhaust side? In the same cylinder, it shoved the intake pushrod through the rocker arm. The lifter is mangled and unusable, but only on this one cylinder. The cam is a Poston 105A. The damage was pretty much done before the car was able to be taken out for it's maiden voyage. There was original trouble to get the car to start, but I broke the cam in to specs. How would this all happen?

Lin,

Bad luck. It just happens sometimes- pretty much all of the Buick cam blanks come from the same manufacturer, and sometimes they just go flat.

This will sound like lame advice, but I would say you gotta just get another one and try again.

Sometimes people will break in the cam using a lighter set of springs (or just the outer springs on the dual valvespring), then replace the springs after break-in. Also, it's a good idea to start with a carb & distributor that are known to be already in good tune, so you don't spend a lot of the break-in time trying to make adjustments under non-ideal conditions...

What do you have for spring pressure?

Now of course I'm assuming you used a "proper" cam break-in procedure, would you want to tell us exactly how you broke in the cam? What is the lift of that cam?

And of course I wouldn't be happy about pushing a rod out like that during break-in, either. Any guess what caused that?

-Bob Cunningham