Bad 460 block causing cam failure?
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Bad 460 block causing cam failure?
I have 20,000 miles on and overhauled 79 460. Looking for more power, I pulled the Erson camshaft and replaced it with a custom grind Comp cams shaft and lifters. I degreed the cam, checked all the usual things. (endplay, lifter bores, lifter preload, etc). The valve springs were checked and are correct for this cam. I pre oiled the motor and it started right up and we held over 2500 rpm for the break in period. This cam went flat before the 30 minute break in was complete. So I pulled the motor, cleaned EVERYTHING (had block jet washed, pulled oil cooler and cleaned, disassembled heads and cleaned,etc) I installed a new oil pump, ran brushes through all oil passages and re-re cleaned everything. Comp sent me a new cam and lifters (same grind) as well as a new timing set. Put it all together again and guess what???? flat cam again!!!
I sent Comp my Erson cam (for reference) as well as the second one it ate and now Comp (Chris padget) is telling me that the problem is that my block is bad and the cam sits too far back in the block. I'm calling BS on that because the original Ford cam and the Erson had no problem living in that block since 1979.
So, anyone had a 460 block that "went bad" or wouldn't hold a cam???
I'm trying a Lunati this time. Would like to hear back from the members before I build this thing again.
Thanks, Speed
I sent Comp my Erson cam (for reference) as well as the second one it ate and now Comp (Chris padget) is telling me that the problem is that my block is bad and the cam sits too far back in the block. I'm calling BS on that because the original Ford cam and the Erson had no problem living in that block since 1979.
So, anyone had a 460 block that "went bad" or wouldn't hold a cam???
I'm trying a Lunati this time. Would like to hear back from the members before I build this thing again.
Thanks, Speed
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Joined: Jul 1999
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I think Comp has a quality issue with some of there cores. I know of three of there cams that wore a lobe in short time recently. I agree with you it's not your block. The retainer plate is what locates the cam. You can also get a custom cam from Erson. I have had them grind some solid roller cams.
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When I read your post I was scratching my head, asking myself how could a block cause one lobe to go flat? If the cam was back to far wouldn't the cam bearings show something? Wouldn't more than one lobe be affected? I second the cam as the problem. I was going to buy a Comp cam for my 460 but I may reconsider after this situation. Please keep us posted. 
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If one or two lobes goes flat, it could be a lifter not able to turn in the lifter bore. This can be because a burr or piece of trash is in the bore and won't let the lifter turn. It can also be a lifter bore that is worn or even a bent pushrod, and the lifter can get cocked and not turn. However in my case what was so unusual is the fact that 14 out of 16 lobes were failing. Lunati says that the lobes (on the custom Comp) had too steep of an angle. If the machine shop gets my parts out by this Friday, I will have it back and started this weekend. I'll let you know if the Lunati lived past break in.
Speed
Speed
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.025 won't fix anything. The cam would have to be way off in order to wear the lobes flat as fast as they are now and I think one could tell by looking at the cam lobes that it didn't line up with the lifters.
Now I had a buddy build a 460 for his drag car and he never could keep the dizzy gear from going bad. he never did solve the problem and I am not sure what he ended up doing. I do know he had the block measured, the dizzy measured and the cam checked and everything was in spec. Now that I think about it he may have bought a new cam again and the problem went away? This was several years ago so sorry for the lack of detail on this. Point is his block was fine.
Now I had a buddy build a 460 for his drag car and he never could keep the dizzy gear from going bad. he never did solve the problem and I am not sure what he ended up doing. I do know he had the block measured, the dizzy measured and the cam checked and everything was in spec. Now that I think about it he may have bought a new cam again and the problem went away? This was several years ago so sorry for the lack of detail on this. Point is his block was fine.
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I was unable to get the 460 running this weekend. I tried to degree the Lunati cam in and it was over 12 degrees out on the back side of the intake lobe and 14 degrees out on the centerline. So now I've ordered a Crane Cam. Can anyone believe this luck?????
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OK Crane is in, runs great. Degreed in nicely. I'm not trying to flame Comp or Lunati, as I have used products from them before. I'm just reporting what I found out this time. I have heard from at least 6 sources that there are only two companies that cast a raw forging for cams. The Comp and Lunati cams looked very similar. The Crane had a distinct look about it. I believe it was a different blank then Comp used and may be why it lived where two Comp cams failed. I'm sure there are MANY people at FTE that use Comp and swear by them. As for me, right now,,, I can't recommend them for use in a 460
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My buddy said he had a crane cam when he had his troubles and when he went to a comp cam problem fixed. His main problem was the dizzy gear roll pin would shear off so he couldn't keep his running long enough to pull it out of the garage.
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For every Cam maker out here, you can find someone that had absolutely no luck with their product. I guess I'm just disappointed that with all of the engineering resources behind Comp, that they chose to give up on me (they gave me a full refund) and blame my block (which is obviously not the problem). Using the 2 Comp Cams has cost me about $1500.00 in parts, machine shop bills etc... I'm not saying that no one should ever buy a Comp cam for any reason,,, but because of my experiences recently, I'd think twice before I put one in a 460.
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Very true. Mine was a hydralic flat tappet for towing. I did ask Comp about that on the first cam and used a fresh stock gear as they recomended. BTW.,,,, Had a 351 W in my drag car that kept eating distributor gears. Changed cams and changed from a high volume oil pump to a stock volume shimmed up for higher pressure and solved the problem. don't know if that 's true for 460's.
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From: Sunny Florida
Originally Posted by Brad4321
Many high performance comp cams require a special gear.