well I got my crane 227 cam in today and right off the bat it looks and measure bigger then my custom ground AI cam?

i measured the dia of the cam and the new one is 1.155 my old AI is 1.086 its has a smaller dia to?

my AI is 218x225 / .544/.541
is this right or was my AI cam has a differant duration then spec?

 

I can't tell by the pics. But what are you saying is bigger? The bearing journals? Base circle?

 

picture is hard to tell but, the bearing surfaces look the same. The "base circles" look like they are larger on the cam that is on the right. Did you double check the part numbers with the vendor?

** I'm very inexperienced with cam stuff ** but, assuming its bigger, wouldn't that mean the valves would not be shutting completely unless you adjusted some other part of the valve train (pushrods)?

 

^Pushrod length will likely need to be changed if the base circle is a different size.

 

the lobe duration is bigger on my new cam, picture on the left the cam on the left... picture on the right cam on the right is bigger..
when I installed AI cam 2 years ago my builder put in 7.3 push rods but AI say that was wrong its suppose to be under 7.2 but now I see why my base circle is smaller.

AI cam specs are 218x225/.544x.541 lsa113
crane cam 210x224/.553x.511 lsa112
but it looks like my AI cam is smaller so did they grind it right or?

click the pictures to see them better

 

The AI cam just has a smaller base circle and less material on the base circle means the lobe can be smaller but still get you the same lift.

You can measure the base circle of the cam and then the lobe lift then subtract. This is "lobe lift". Multiply this by your rocker ratio and you will get the valve lift.

Really no way to check the duration, LSA, etc with out a Cam Dr.

Lloyd

 

Lloyd is right, that is why its so crucial to always measure pushrod length when you install camshafts because the base circles can be different.

 

+1 for Lloyd. Many times, cam vendors will reduce the base circle to add duration and lift. If not, it would be impossible to add duration and lift in some engines.