Installed the Comp Cams XFI 218 cam in the block today. Degreed it and took some measurements on the intake side. By the way did a preliminary with the cam in another motor and the exhaust side of the cam was pretty much on except the lift was lower than listed around .005" with number seven cylinder the worst. The following are from cylinder number one.

Actual duration at .050" lift is 220 degrees not 218 as advertised. If installed straight up the cam is listed as 109 ICL. It was actually 108 ICL. The lift on the intake valve was .355" which works out to .568" with the 1.6rr. Just for giggles we did the lift on cylinder numer 3 intake and it came up with .352" lift whitch works out to .563" lift.

I'm going to install the cam on a 112 ICL by retarding it 4 degrees. DynoSim says that is the best overall for what I want out of the motor. I gain like 12+ horspower on top with not much loss under 3500rpm. I can stand to loose 5 foot pounds of torque down low. Having traction problems as is. By the way the cam is going into an L98 motor.

For what its worth we used the big Moroso degree wheel and you can get that sucker down to 1/4 degree with no problem. So we were able to get pretty accurate measurements. Also used the Cloyes 3145 timing chain set.

 

I had the cam put on a "Cam Doctor" at Chet Herbert's to see exactly what the grind was. I looked over the printout at the time and was a little skeptical if they did it correctly. Now that I have had a chance to degree the cam in the motor the numbers are pretty close to each other. Here is what the cam doctor said that the XFI 218 cam really was.

Intake duration at .050 was 220.7 degrees. Closer to a 221 degree cam than the 218 advertised. Intake duration at .006 came out to 270.4 which is more than the advertised 268 degrees. Lift was .356 on the intake lobe. ICL came out to 108 the same as we degreed. Advertised ICL if installed straight up is 109. LSA was 112.4. Advertised LSA was 113.

Exhaust duration at .050 was 225.6. Duration at .006 came out to 273.9 degrees. Lobe lift was .351 inch. All this by the way was for number one cylinder.

Also it stated that number seven exhaust was lower than the other lobes. We checked it and it was about .005" lower than it should have been. Hope some of you find this information usefull. At least this particular 218XFI cam is a little larger in duration than advertised which was a pleasant surprise for me. One thing I have been finding on this rebuild is you have to check everything and take nothing for granted. I have had quite a few surprises along the way as things were not quite as advertised. Knowing the errors I was able to make adjustments to get thing back to where I wanted them. I can see why some build ups will have more power than others.

 

Don't put the cam in based on DynoSim suggestions. The cam is ground with that advance on purpose, if you wanted more top end a different cam would be the key.

Bret

 

Thanks Bret. I will take your advice as you have way more experience on these matter than I do.