I know many have said the only reason we have cam lobe failures is improper break in and improper ZDDP quantities, I still can't help having the nagging feeling that the narrow lobe cams are closer to that razor edge of failure. Now while I have not actually crunched any numbers it seems the wides still have less issues.
One other issue in my own personal build which was with a Mopar 229, is that my cam would not fully install, it would get stuck when reaching the last set of bearings. I WAS able by way of turning the cam around to get the front of the cam in the front cam bearing, and with the rear cam plug removed, the rear of the cam in the rear cam bearing meaning the issue was with #2 or #3 cam bearing/cam journal. It also did this with the stock cam. I took it back to the machinist with BOTH cams, he called back and said after installing a new set of bearings it did the same thing and he ending up have to hone the #3 block journal, and install a 3 set of cam bearings. Then it hit me that #3 is almost always the cam bearing that fails. Coincidence?
Here are some pics of AMCEagles narrow cam in his block, it would seem to me that in that particular lobe and lifter bore there would be very little if any lifter spin, the edge of the lifter is NOWHERE near the edge of the lifter bore. Now what causes THAT? If we can answer that I think we can come up with a fix for all cam longevity issues. Are the narrow cam cores meant to line up with 4.2 lifter bores vs 4.0 lifter bores, is there a difference? Should narrow cam cores be used with 4.2 cam gears, which may allow the cam a more rearward position, is there a difference? And I don't mean a part # difference but a measurement of an actual 4.2 cam gear an current 4.0 cam gears, with regards to how far they push the cam in. AND could all of this explain cam/distributor gear failures, as it relates to cam installation depth.
I have included an OPTIMAL cam lifter diagram and AMCEagle's installed narrow cam lobe/lifter relationship pics.
Wide Vs Narrow Lobe Cams
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- SilverXJ
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Re: Wide Vs Narrow Lobe Cams
That is nearly centered. What does the lifter pattern on that lobe look like?
A single block isn't a good sample and could just be put off as a machining error.
A single block isn't a good sample and could just be put off as a machining error.
2000 XJ. 4.6L stroker
00+ Viper Coil Swap | CPS Timing Increase Mod | Fabricated Airbox | Dash bezel, Arduino Multigauge & RD Conceal
Eat, breath, drink, sleep, Jeep, drink
00+ Viper Coil Swap | CPS Timing Increase Mod | Fabricated Airbox | Dash bezel, Arduino Multigauge & RD Conceal
Eat, breath, drink, sleep, Jeep, drink
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- Making Progress
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Re: Wide Vs Narrow Lobe Cams
On my wide lobe 229, the edge of the lobe is at the edge of the lifter. If someone has trashed wide and narrow lobe cams, I would like to compare them, and I would pay to have them shipped to me. I would like to check where the centerline of lobes are in relation to the face of the cam. IE, was the width added equally on each side or all on the front or rear.
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