Cam break in procedures
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
Cam break in procedures
When breaking in a cam, the manufacturer recommends that the engine must be run at an certain rpm for a certain amount of time. (ie 1500rwpm for 20 min) How does one go about keeping the engine at the required rpms without allowing the rpms to drop? A person's foot would get tired if they try to keep the same amount of pressure on the pedal and afterwhile the engine noise will get to you. So what does one use to keep the engine at the required rpms for proper break in of the cam?
Melting Slicks
Joined: Oct 2008
Posts: 2,154
Likes: 69
From: Regina Sk Canada
Have a buddy help you out, get it running asap not a lot of cranking. If your alone, take a screw driver and crank the idle up one full to 1.5 turn, that will keep it running till you can get out there and turn it up to where it needs to be. I was told 2000 for 30 min.
Burning Brakes
Joined: Dec 2003
Posts: 1,149
Likes: 153
last time I changed the cam I read the proper way to do it was bring it up to 2500 rpm and vary it to 2000rpm for 30 minutes,don't keep it steady at one rpm.I'm pretty sure I got that info off the forum or Comp Cams website.That cam is still running strong.
Le Mans Master
Joined: Oct 2007
Posts: 7,444
Likes: 970
From: Tennessee/Rhode Island
I have read the same from comp cams website but keep wondering how GM broke in the OEM cam from the factory since I know that they did not run new engines at 2-2,500 RPM for 30 minutes to break in the cam. Heck-all they did was start it to drive it off the assembly line. How did they do it from the factory if they did it at all (I don't think so)?
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
I have read the same from comp cams website but keep wondering how GM broke in the OEM cam from the factory since I know that they did not run new engines at 2-2,500 RPM for 30 minutes to break in the cam. Heck-all they did was start it to drive it off the assembly line. How did they do it from the factory if they did it at all (I don't think so)?
Racer
Joined: Oct 2006
Posts: 255
Likes: 3
most performance cam grinders want you to run the motor at 2000 - 2500 rpm for 20 minutes. You should vary the rpms as you keep it running. When I did my last one I just sat in the drivers seat and kept vary the throttle. It gets rather boring! Make sure you have your coolant full before you start and watch your gauges. As stated in an earlier reply make sure you have plenty of cam lube when assembled and the oil you are using has ZDDP additive.
Rodney
Rodney
Last edited by rod7515; Feb 27, 2011 at 09:02 PM.
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Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
My question is can the idle speed screw be turned up to the recommended rpms or must you keep your foot on the gas pedal? The reason I'm asking how it is done so when I swap my cam that I break it in right. I did not do this the last time I rebuilt this engine (2004)
Melting Slicks
Joined: May 2006
Posts: 2,590
Likes: 403
From: Nashville TN
St. Jude Donor '09
Yes, turn the idle screw up to the desired RPM; I used my timing light to set. Had a buddy actually crank the motor and watch the gauges. Had another friend watching for leaks. I followed the cam manufacturer's recommended procedure. Lunati recommended taking up to 3000 RPM for a period of time . . . my neighbor said it sounded pretty good from inside his house. 
when I broke my 427/435 in with open headers in my garage
Race Director
Joined: Mar 2008
Posts: 15,161
Likes: 17
From: coffee
Is this procedure the same for hyd. flat tappet and roller cams?
I'm getting perilously close to being able to fire my new crate engine (flat tappet) up for the first time, so I have to set the timing and everything too. I've got Comp break in oil.
I'm getting perilously close to being able to fire my new crate engine (flat tappet) up for the first time, so I have to set the timing and everything too. I've got Comp break in oil.
Melting Slicks
Joined: May 2009
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Race Director
Joined: Sep 2004
Posts: 11,874
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
roller cams dont need the break in since they have rollers....the break in is to allow or "train" the hydraulic lifter to spin on the cam shaft and to promote that wear pattern on the bottom of the lifter....if the lifter doesnt spin you wipe the lobe
Race Director
Joined: Mar 2008
Posts: 15,161
Likes: 17
From: coffee
Thanks for the explanation, I had never heard that part before. I do worry about letting it idle (presuming it will) while trying to get the timing set. Hopefully this is a minimal risk.
Melting Slicks
Joined: Feb 2004
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Melting Slicks
Joined: May 2006
Posts: 2,590
Likes: 403
From: Nashville TN
St. Jude Donor '09
Just set the timing close enough that it will run and then take it up to the desired RPM for break-in. As long as you lubed everything up real good when you installed cam you should be okay. Make sure to use some good oil with high zinc rating. I used Brad Penn break-in oil on mine -- just a little extra insurance.
Race Director
Joined: Mar 2008
Posts: 15,161
Likes: 17
From: coffee
Just set the timing close enough that it will run and then take it up to the desired RPM for break-in. As long as you lubed everything up real good when you installed cam you should be okay. Make sure to use some good oil with high zinc rating. I used Brad Penn break-in oil on mine -- just a little extra insurance.
Now I'm thinking I might need to get the exhaust sorted before I start it up. 20 minutes with open headers would have the whole neighborhood calling the cops on me.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
It is a GMPP crate engine that has been sitting who knows how long since it was assembled (at least two years in my posession, don't laugh). I will be priming it and turning the engine over as I do.
Now I'm thinking I might need to get the exhaust sorted before I start it up. 20 minutes with open headers would have the whole neighborhood calling the cops on me.
Now I'm thinking I might need to get the exhaust sorted before I start it up. 20 minutes with open headers would have the whole neighborhood calling the cops on me.
did you change the cam in this? if not i am pretty sure the cam is already broken in