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Old 03-24-2009, 10:42 AM   #1
bigmike25rs
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Default What does it mean to "break in cams"

I've seen this more than once on here and it boggles my mind.. How exactly are you suppost to break in new cams? I guess I understand if you trying to get the coating off of the lobes or something like that.. I've heard a few goofy theories about how to it as well.. I just put in a set of 11.3 Kelford 272's and I have no intentions of any sort of break in.. Can someone explain this to me??
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Old 03-24-2009, 11:14 AM   #2
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You should break in your cams, it will prevent flattening of the cam lobes.

make sure you use EOS and not Synthetic for the break-in period.

It is basically a poor-mans form of heat / use treating, similar to tempering from what I have read.

If I were you, I would just do it for the sake of peace of mind, if nothing else. Plus if you don't break them in, and you have a problem, the manufacturer may not honour their warantee...

GL with whatever you choose to do!
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Old 03-24-2009, 11:23 AM   #3
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Skipping cam break-in = problems. I ran mine at 2k rpms for 30+ minutes to break them in. It's not like you're doing a 1000 mile breakin or anything.
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Old 03-24-2009, 11:34 AM   #4
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Quote:
Originally Posted by jays05 View Post
Skipping cam break-in = problems. I ran mine at 2k rpms for 30+ minutes to break them in. It's not like you're doing a 1000 mile breakin or anything.
yup...most companies recommend about 2krpm for 20 minutes...don't use synthetic oil either, as already mentioned.
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Old 03-24-2009, 02:43 PM   #5
bigmike25rs
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Ok, that makes sense.. I'm not sure why Kelford has nothing about it on their spec sheet though.. I just figured since the cams were steel and everything in the heads is aluminum that nothing could really "break in" as far as the cams.
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Old 03-24-2009, 03:30 PM   #6
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cam break-in comes from the days of flat tappet cams when you absolutely HAD to break in the cams or you'd risk wiping the lobes. To do this you don't want to run the engine at one rpm, you want to vary rpms to make sure you get an even wear pattern. Doing this meant each cam lobe was "broken-in" to it's corresponding lifter and also meant when rebuilding you always had to reinstall the lifters in the original bores they came out of.

I have a feeling with our suby motors, while not as critical as with a flat-tappet cam, the cam lobes do somewhat "mate" with the buckets which is why some guys recommend a break-in procedure.
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Old 03-24-2009, 07:03 PM   #7
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If cam breakin was so important way dont OEM's do it? evos come with full synthetic with aluminum heads and steal cams. Subies dont come with some crazy cam break in either just the normal motor break in. Crap my motor was a demo and never even got the oem break in and has 109k with no problems. I think cam break in has gone the way of lifters and pushrods.
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Old 03-24-2009, 07:12 PM   #8
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Originally Posted by scby rex View Post
If cam breakin was so important way dont OEM's do it? evos come with full synthetic with aluminum heads and steal cams. Subies dont come with some crazy cam break in either just the normal motor break in. Crap my motor was a demo and never even got the oem break in and has 109k with no problems. I think cam break in has gone the way of lifters and pushrods.
When you buy a car you weren't the first one to run the engine. I've never seen an engine with zero miles on it on a lot.
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Old 03-24-2009, 10:31 PM   #9
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Quote:
Originally Posted by bigmike25rs View Post
Ok, that makes sense.. I'm not sure why Kelford has nothing about it on their spec sheet though.. I just figured since the cams were steel and everything in the heads is aluminum that nothing could really "break in" as far as the cams.
kelford puts their breakin procedure on the back of the spec sheet nad it is also on hteir website.It is very crucial for it to idle at 1800-2000 for the first 20 minutes.
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Old 03-24-2009, 11:32 PM   #10
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Originally Posted by kellygnsd View Post
When you buy a car you weren't the first one to run the engine. I've never seen an engine with zero miles on it on a lot.
sense when does the odometer monitor how long the motor has been on?
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Old 03-24-2009, 11:58 PM   #11
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If you look hard enough I'm sure you'll find some documentation about how to break in your cigarette lighter. I drive my fresh built motors and trans like I drive at Bondurant. Call me lucky or crazy, but I believe in advances in technology.
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Old 03-25-2009, 12:35 AM   #12
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sense when does the odometer monitor how long the motor has been on?
It doesn't but at least you know the engine has been run at the factory and driven and possible idled for a bit at the appropriate rpm for cam break-in. Probably a stretch but one can dream can't I
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