I have a couple of cam questions. After breaking in a cam and running about 1000 miles how close should you be to the manufactures lobe lift number? I know there is some wear during break in but what would be consider normal or should the measurement I get be exactly what the card says? How much variation in lobe lift should you expect to see from lobe to lobe on a camshaft after it is broke in? I am running an Isky Z60 solid flat tappet cam that is supposed to have a lobe lift of .365". I just finished checking all lobes using the lifters for the cam and pushrod with a .0001 digital dial indicater and got readings from a high of .3620 to a low of .3565. Most of the lobes(11) were between .3590-.3600 and I saw no unusal wear on the lifter bottoms that would point to a bad break in. Is the variation I am seeing something to worry about or is it normal??

sorry for the double post!

No one has an opinions or comments to offer on this?

I did speak with an Isky tech person today and he saidas long as there was no more than .010 difference between all of my readings that it would be ok. He also suggested readings more than .025 less than the design lobe lift would be a good indicator that that particular lobe was on it's way out.

Anyone know how to read UDHarold over at Holley/Lunati? I have heard nothing but good things about Harold and his great knowledge of cams and cam design and I thought I my give him a try.

.010 is too much IMHO. It should be a couple of thousandths at the most or I would be pulling it.

-Mark.

I would right that up for manufacturer tolerance. From what I was told by UD harold, the machines at the high volume manufacturers have 17 seperate grinding wheels, 16 for lobes and 1 for the fuel pump eccentric. If those wheels are not dressed perfect with each other you will have some variance.

Thx guys!! I posted the same question over at the 2ng gen camaro board and I am getting pretty much the same comments......nothing to worry about smile.gif . As I indicated I don't see any unusual wear on any of the lifters, they all still have a very slight crown to the end. I can see this very easily by holding a straight edge to the contact face of the lifter and see that there is light near the OD of the lifter and contact in the cemter. A few fo the lobe that I was able to look at were shiny and polished on the peak of the lobe with no visable galling, scoring or wear patterns of any kind. Perhaps I was just being paranoid about losing lobes on my cam?