Going off memory 283 300 @ .050 .824 .810 gross 114 lobe separation. I don’t have the card in front of me but I think those numbers are close.

It’s 5150 or 5160 whatever core comp uses. Everything yields before failure so it ‘could’ be twisted, who knows for sure.

quote:

Originally posted by I Hate Dragsters:
Going off memory 283 300 @ .050 .824 .810 gross 114 lobe separation. I don’t have the card in front of me but I think those numbers are close.

It’s 5150 or 5160 whatever core comp uses. Everything yields before failure so it ‘could’ be twisted, who knows for sure.

Good eye/nose. Good you caught it.

Experienced.

Chances a cam would twist and still fit smoothly in the journals is about the same as winning the Powerball Lottery.

Do you know this from experience?

If it's twisted, chances are slim to none it is not bent.

If cam timing checked out on 1 and 6 we know it hasn't twisted in the center. If it is twisted, it's twisted behind the front journal, that's why I keep saying turn it around and stick it in backwards. I could see it possibly clearancing the front cam bearing itself, running bent/twisted.

Bent is bent, whether it's bent .002 or .010.

Chances of it twisting and not being bent are ultra low, like winning the lottery ultra low, Busted Knuckles is right.

Common sense.

Once i get the engine hoist returned....i'll give some updates.

I would bet it could twist and still turn freely in the bearings. We have all seen cam twist using a distributor to trigger timing and the cam still slides in and out. If the cam took a set with that twist why would it have to be bent?

Now would I bet that it is twisted? No I wouldn't but the cam doctor will tell you.

For a camshaft to standardize itself 3-4 degrees retarded, it would have to twist a lot more than the camshaft twist which is associated with timing.

I checked exhaust p to v after verifying that valve timing was @ 126(jumped tooth is 13.33 degrees, plus the mystery 2.67 degrees). I had 0.007" clearance.

When i degreed the cam in after the last repair @ 110, i had 0.130" clearance. Breaking out the calculator that's 0.0077" per degree at the valve. Based on that finding 2.67 degrees is worth ~0.0206" at the valve, with 1.7 rocker ratio. With that math does that show that the cam is retarded ~0.0121" (arc length) @ the lobe? 0.0206"/ by rocker ratio. Does that make sense??

all this nonsense about whether it twisted or bent or not is meaningless at this point. Bottom line is the black core is problematic, you need a new cam and want the gold core.



Oh and my black cam core showed evidence it did twist before it broke at idle.

This message has been edited. Last edited by: 1320racer,

quote:

Originally posted by 1320racer:

quote:

y

all this nonsense about whether it twisted or not is meaningless at this point. Bottom-line line is you need a new cam and want the gold core.

Oh and my black cam core showed evidence it did twist before it broke at idle.

Don't disagree with you, I've already spoke with my cam manufacturer of choice. And yes when i last put the engine together I wasn't fond of the 5150/5160 core.

I'm not the type to accept something is f'd up and toss in the scrap heap and go on with my day, i want to know to as much as possible about the failure. The more I know the happier my f'd mind is

you already know why it failed...black cam core!

quote:

Originally posted by 1320racer:
all this nonsense about whether it twisted or bent or not is meaningless at this point. Bottom-line line is the black core is problematic, you need a new cam and want the gold core.



Oh and my black cam core showed evidence it did twist before it broke at idle.

Gold cores, hands down! Don't use the others. And if you are running a decent lobe lift, around .500 and up in a BBC with a standard core cam, I'd consider a tool steel cam.

my bad...you're right

quote:

Originally posted by I Hate Dragsters:
I'm not the type to accept something is f'd up and toss in the scrap heap and go on with my day, i want to know to as much as possible about the failure. The more I know the happier my f'd mind is

There is nothing wrong with that. The more ya know, the more ya know.

Once I got the cam out and wasn’t at some goofy angle trying to use a small vee block to see the pin in the car, It was easy to see that the pin is in fact bent. Case closed. Turn this thing into wall art! I appreciate everyone’s help and input.