Today I was applying extra lube my cam lobes in preparation for installing my new lifters and pushrods when I happened across a lobe that has a chip in it! This is a brand new custom turbo cam from Scott Brown hat has been nitrided . . . I really hope I don't have to go through the removal/replacement process. I guess it's possible that I could have done this while installing the cam, but I was reallllly careful to try and minimize knocking the cam around. I would think I'd have to hit it pretty damn hard to do this. What do you all think? Bad enough to pull and try to get a new one?
Where does the lifter ride, as they always ride offset to one side of the lobe. It looks like te chip is on the up hill of down hill side of the lobe from what I can tell in your photo, and even if the lifter does happen on ride on that side of the lobe then as long as the chip is not on the nose of the Cam I think you would be good to go if you pulled the Cam and carefully polished over that area! It should need no more then a .006" radius polished into be nothing to fret about.
It appears to be casting flash which is kinda normal for a cast iron part. I don't think it will cause ANY problems, BUT can't guarantee that. Too bad you didn't notice it BEFORE installing. The best thing to do in my opinion is to call Scott Brown & send him some pics & get his advice. Tom T.
Looking at the other images, there are areas of rough casting (unmachined areas), on the cam and looking at the lobe it is the same, so I am pretty sure you are fine. Set the lifter on that lobe and rotate the came and see where the lifter face contacts the lobe all the way around, and you will know if it the face and that area intersect. It looks like the lifter face will be well inside of that edge.
Well I emailed the same pictures above to Scott Brown and here's what he said: "It looks as though the chip or imperfection was there before the grinding of the lobe. If you run your finger across the ground part of the lobe, is there any burr that is raised above the lifter mating surface? If there is a burr, the I would not risk it, and let’s replace it. It will take a little time but I’d rather be safe than sorry, and have you encounter a problem. If there isn’t a burr I would say it was likely a casting imperfection before it was ground. Either way, if you are uncomfortable with it I would be happy to exchange it for you." I ran my fingers over the area today trying to feel for any burr and it feels like it was ground after this imperfection was there, nice and smooth. So I'm planning on running it as is, and having Scott's and your guys advice does make me feel better! Scott is being very nice about offering to replace the cam as well. Here are some pictures with the lifter: Even though the lifter is bigger than the lobe because the lifter face is convex I'm pretty sure the contact patch is narrower than the width of the lobe. Is that how that works?
In the pictures that lobe doesn't even look like the other lobes. Perhaps the lighting, but it looks like the surface of that lobe has a porous or orange peel look to it compared to lobe next to it. Where did the chip go? If you do have to take it apart you may want to deburr that lifter valley a little.
Honestly it looks ok to me. Scotty is a trustworthy guy. He is right, either swap it out now or take your chances. I could go either way.
If it were chipped, the iron where the chip fell off would be gray/lighter than the rest of the rough casting, in the pic it looks like it was cast that way, your probably fine.
