A few day ago I posted about a popping through the carb noise. Turned out to be an exhaust lobe rounded off. Comp cams gave a few suggestions as to a possible cause, but when I took it apart I noticed the cam had to much endplay. I did not measure it with the old cam, I'll wait and check it with the new one, but I wondered if that could cause just one lobe to ware off. The rest of the cam looks like new. Any thoughts would be helpfull. Thanks

 

Is it a stock cam? Stock springs? How about lifters? Probably a bad lifter or too much pre-load. Is it hydralic or solid?

 

How much end play did it have? I find it hard to believe that end play was the cause. Camshaft end play is controled by the cam retainer and timing chain sprocket. The only way your endplay could be off is for something to be wrong with one of them.

If it only got one lobe it was probably because that lifter didn't spin for some reason.

Be sure to clean the inside of the motor and ALL oil passages good before putting it back together. Also clean the inside of the oil pump.

 

I agree. Another Comp Cam gone south. This is the third cam I have read on this board in recent months that one lobe went bad two on one guy now this one, the one common thing ALL COMP CAMS.

 

I had the same prob with Delta cams......I put in an Edelbrock, and havent had a problem since.

 

Kermmydog, read on a lot of other sites, and yes you will notice a lot of comp cams having hte problem but when you read deeper you also find that there is a lot of other cams doing the same thing it's just that comp is one of hte most prevelant cams used for upgrades. I have seen guys doing it to edelbrock, crane, herbert, and even reed custom ground units. One common issue all flat tappet hyd cams. causes seem to be the epa mandated reduction in zinc in the oil, and someone else mentioned that there is only 1 or 2 companies that are making lifters anymore, and it's a problem with the lifters also. Cures don't be cheap when buying hte lifters, and using GM-EOS in your oil, and have heard of a lot of guys running shell rotella 15W-40 diesel motor oil on initial break in. also if it's on an initial rebuild have the machine shop hone the lifter bores.

 

So what I'm hearing you say is since the mid 80s, " that's the last engines I have built" , ZINC in the oil stopped this problem. I have built over 100 engines in my life and never had a cam failure. I must be slow because this makes no sense to me at all. Getting a cam with poor temper, not hard enough or lifers that are harder than the cam now that I can understand. I'm not tring to be a smart A-- but I work with metal everyday I really can't understand this situation. The other reason I want to find answers is I want to cam my truck, These issues sound like a quality assurance problems, of the cam manufactures, not break-in issues. I really would like someone to discuss this with, like maybe e-mail or message.
Thanks, Craig

 

yes I am saying the zinc in the oil or lack thereof is the major issue it seems with cam break in, that and too much spring preasure on breakin, the issue seems to be poor qualitly in the lifters also if they are not right then they won't wear on the cam properly and instead of making a wear pattern that works they break through the hardened part of the cam lobe (remember flat tappet cams are not hardened steel but rather Iron that is surface hardened break through that .060 thick max hardening, adn it's soft iron from there on). It seems that people that do run the EOS in the breakin oil experience much less initial cam failure rates than people that just use any modern oil, which would indicate that the oil is the problem not quality of the cam. but a quality issue does seem to be a problem lately on the lifters, some of it's in the hardness or lack there of ,and an inconsistant machining of the base, and dia which either would also cause some of the problems if the lifter is not spinning in the lifter bore. one thing also to consider is that modern cam profiles are a lttle more agressive than they used to be expecially in things like the extreme series of cams so the zinc is even more of an issue to properly lubricate the cam during the initial breakin period. BTW if you want you can email or PM me.

 

It is interesting to note that Delta cam uses a company in Detroit michigan by the name of engine power components to source its cam blanks. This is the very same company that supplies cams to elgin, sealed power, edelbrock, and all comp cams grinds dash 5 and up. In light of this I am not inclined to believe that there is a cam core quality issue.

Of the very few cam failures I have seen with my clients and products the over riding causative factor was improper break in.

I have noted a greater rate of cam failures mentioned on the boards of late. I am more inclined to believe it is an issue with lifter quality, hardness or crown finish when a cam fails upon break in than a cam quality issue. Long term failure may well be caused by declining amounts of zinc di thiophoshpate (sp) in our motor oils today.<O></O>

I recently did a truck build for a client utilising a new cam billet from delta. Comp X4262h 218/226 @ .050 with .530"/.540" lift on a 109 LSA. I broke in the cam with comp 924-16 dual springs. I DID NOT remove the inners but pre oiled the engine before lighting it up and use moly on the cam lobes and lifters. This combo fired immediately upon first crank and this I believe is a key issue with break in. The longer you crank the engine in a no start scenereo the more likely you will have cam issues.

I broke this cam under those circumstances to test this cam break in failure issue I have been hearing about of late. I DO NOT recommend that anyone try this on their own as I made allowances to ensure the cam was not wiped out during break in.

Regards,
SMJ/RHP
http://reincarnation-automotive.com
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I had the same problem on my 460 before. My new motor I have now, I cut a groove in the lifter bore to provide better lobe lubrication.

 

what monster said is very true. just don't use a new sm rated oil in a flat tappet cam engine.sl is fine but sm is not it is very very weak take a look over at BITOG.