My CompCams Cam Card ECL Question

[Tuner]

I think it's a prank, just to get a rise out of the OP and see if the he is actually measuring or paying attention. Perhaps the CC tech line guy thought he was being played a little bit and just wanted to play along to see what happens next.

[Monza355]

5 minutes ... really?
The width of a line on a degree wheel is more than that.

.05 X 60 = 3..... 3 minutes

It is half a second … On the minute pointer so it’s not even measurable. 1 minute on a clock every 6 degrees remember.
I don’t know how big of a degree wheel you would need to get an accurate measurement on this error. But I doubt the regular at home engine builder has one

[Tom68]

It is half a second … On the minute pointer so it’s not even measurable. 1 minute on a clock every 6 degrees remember.
I don’t know how big of a degree wheel you would need to get an accurate measurement on this error. But I doubt the regular at home engine builder has one

Degree wheel on the crank, lifter bore alignment, cam chain, sprocket runout.

There is no accuracy.

[Tom Walker]

The more I think about it Tuner, you may be right.
Somebody probably pulling somebody's chain or they have a degree wheel that has a diameter bigger than would fit in any of our shops

[cknight]

Just guesstimating, but Comp may have paired non-symmetrical intake and exhaust lobes from different design families that have different offsets from seat timing to .050" timing, in order to achieve your requested specs. I wouldn't panic.

[cknight]

Just guesstimating, but Comp may have paired non-symmetrical intake and exhaust lobes from different design families that have different offsets from seat timing to .050" timing, in order to achieve your requested specs. I wouldn't panic.

[bigpoppapreston]

Just guesstimating, but Comp may have paired non-symmetrical intake and exhaust lobes from different design families that have different offsets from seat timing to .050" timing, in order to achieve your requested specs. I wouldn't panic.

The lobes are from different design families.

The intake lobes are QXX. While the exhaust lobes are LXL.

[bigpoppapreston]

The cam card is odd and precise. I would check that cam with a wheel for sure. I assume it was a custom grind? Close to a Crane F-278-2 solid flat tappet but just a bit more exhaust timing. Cast iron exhaust manifolds maybe?

I have an old Isky cam with rounded up valve timing numbers on the card. I guess it was to avoid decimals in the spec from confusing people, but who knows?

It is indeed a custom camshaft. I have quite a bit more exhaust duration because it has full exhaust including tail pipes (long tube headers) but primarily for power to hang on after peak. Thanks

[bigpoppapreston]

[hoffman900]

What are the odds the crank is even indexed across all cylinders?

As I said, between the cam and valvetrain flexing in a firing engine, and going into and out of resonance, and the crank doing the same, it’s really 5-10* off and which cylinder and when varies.