how do you break in a cam?
Thread Starter
Intermediate
Joined: Dec 2005
Posts: 31
Likes: 0
From: warfordsburg PA
how do you break in a cam?
I just installed a cam in my 350 and put on the lube for the cam and lifters then fired it up and let it run for an hour varying the rpm like my friend told me to.then changed the oil and went for a ride and when i got home it was ratteling.when i tore it down i had a lobe worn off the cam.Ithe cam i pulled out was a 520 lift cam dynamics and it worked fine but was not good with the higher gears i put in so i went with a smaller cam .474 i think and it ran real well until it tore off the lobe.
so any good advice on a cam install? how long do you let it run,what rpm?thanks
so any good advice on a cam install? how long do you let it run,what rpm?thanks
Burning Brakes
Joined: Nov 2001
Posts: 1,189
Likes: 2
From: Austin TX
What I've always heard, read and done, is fast idle the engine at about 2000 rpm for 20 minutes and don't vary the rpm.
This tech bulletin from comp cams about how the lubricity of modern oils has changed, and the impact that has had on flat tappet cams, is interesting.
http://www.wildgooseperformance.com/news.html#tech
Dan
This tech bulletin from comp cams about how the lubricity of modern oils has changed, and the impact that has had on flat tappet cams, is interesting.
http://www.wildgooseperformance.com/news.html#tech
Dan
Last edited by danno85; Mar 25, 2006 at 10:27 AM.
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First use the cam lube they send with it on the lobes and the lifter bottoms.
MAKE SURE that you have it timed properly so that it starts INSTANTLY. Don't want to crank on it a long time.
Make sure carb is full of fuel before you spin it over.
You DO want to vary the rpm. A cam is lubed by slash lube and you need to change the rpm occasionally to throw it to different places. One constant rpm can starve it on particular lobes.
Get some GM EOS...put a can in it with some good plain 'ole Dino oil. The diesel stuff is always a good idea. Rotella or Delo400 or some Valvoline Race Oil. I wouldn't use synthetics for this part.
I would overfill it a qt during cam break in to help throw some oil around in there.
Are you sure you had lifters adjusted right at start up? Or at least pretty close?
Good luck with new setup!!
JIM
MAKE SURE that you have it timed properly so that it starts INSTANTLY. Don't want to crank on it a long time.
Make sure carb is full of fuel before you spin it over.
You DO want to vary the rpm. A cam is lubed by slash lube and you need to change the rpm occasionally to throw it to different places. One constant rpm can starve it on particular lobes.
Get some GM EOS...put a can in it with some good plain 'ole Dino oil. The diesel stuff is always a good idea. Rotella or Delo400 or some Valvoline Race Oil. I wouldn't use synthetics for this part.
I would overfill it a qt during cam break in to help throw some oil around in there.
Are you sure you had lifters adjusted right at start up? Or at least pretty close?
Good luck with new setup!!
JIM
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Assuming all else was well, I'd also suspect an adjustment problem. Is this a flat tappet engine? I'm guessing that it is. Even so, .520" lift is not that radical and you should not have had a problem. Still though, it's sometimes advisable to break in a new cam with lighter springs and then switch to the heavier, appropriate ones for the application.
Race Director
Joined: Dec 1999
Posts: 19,610
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From: Forked River NJ
I run at 2000 rpm with a slight blipping of the throttle to vary the rpm. I run double springs and always remove the inner spring for break in. I run Valvoline Racing oil for break in and from then on. Much better lubricating package. I have never had one fail on me.
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Racer
Joined: Mar 2006
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From: Esparto ca
I've always been told to run non-detergent for breakin. On my last engine I was told TRY to run non-detergent, if you cant find it run castrol 20wt. Is non-det. still being used for breakin or is that dead and gone?