Cam break in procedures
Melting Slicks
Joined: Jul 2006
Posts: 2,373
Likes: 6
From: Baltimore MD
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
Race Director
Joined: Mar 2008
Posts: 15,161
Likes: 17
From: coffee
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Thanks for the explanation , I just always "assumed" the higher rpm was for more oil volume. 
Race Director
Joined: Mar 2008
Posts: 15,161
Likes: 17
From: coffee
FWIW, if anyone is running across this, here is the official break-in guidance from the manual that came with the engine (290hp GMPP 350)
This process seems more focused around what I have heard described as "seating the rings" rather than a cam break in, so perhaps they do break in the cam from the factory.
7. The engine should be driven at varying loads and conditions for the first 30 miles or one hour without wide open throttle (WOT) or sustained high RPM accelerations.
8. Run five or six medium throttle (50%) accelerations to about 3000 RPM and back to idle (0% throttle) in gear.
9. Run two or three hard throttle (WOT 100%) accelerations to about 3000 RPM and back to idle (0% throttle) in gear.
10. Change the oil and filter. Replace with 10w30 motor oil (non synthetic) and a PF454 or PF1218 AC Delco oil filter. Inspect the oil and the oil filter for any foreign particles to ensure that the engine is functioning properly.
11. Drive the next 500 miles under normal conditions or 12 to 15 engine hours. Do not run the engine at its maximum rated engine speed. Also, do not expose the engine to extended periods of high load.
12. Change the oil and filter. Again, inspect the oil and oil filter for any foreign particles to ensure that the engine is functioning properly.
8. Run five or six medium throttle (50%) accelerations to about 3000 RPM and back to idle (0% throttle) in gear.
9. Run two or three hard throttle (WOT 100%) accelerations to about 3000 RPM and back to idle (0% throttle) in gear.
10. Change the oil and filter. Replace with 10w30 motor oil (non synthetic) and a PF454 or PF1218 AC Delco oil filter. Inspect the oil and the oil filter for any foreign particles to ensure that the engine is functioning properly.
11. Drive the next 500 miles under normal conditions or 12 to 15 engine hours. Do not run the engine at its maximum rated engine speed. Also, do not expose the engine to extended periods of high load.
12. Change the oil and filter. Again, inspect the oil and oil filter for any foreign particles to ensure that the engine is functioning properly.
Drifting
Joined: Jul 2004
Posts: 1,556
Likes: 91
From: Skiatook. Oklahoma.
When I'm ready to break in a cam, I connect my remote starter switch up to the starter. That way I'm right at the Carburator at engine start-up and I can get the RPM's up as soon as possible. I can also keep an eye on everything at that moment and make quick adjustment's instead of peering through the Windsheild.
Marty.
Marty.
Melting Slicks
Joined: Apr 2006
Posts: 2,084
Likes: 14
From: Airdrie Alberta
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.
Especially when my next door neighbor is one!
Racer
Joined: Dec 2008
Posts: 297
Likes: 19
From: arlington TX
I fired off the new motor with new cam and heads a few weeks ago. Used LOTS of cam break-in lube on cam and lifters, ran Valvoline Racing oil (VR1) with a bottle of Comp Cam Break-in additive. I had high pressure springs, so I took out the inner springs to break-in the cam with less pressure on the lifters and lobes. Ran for about 20 minutes at about 2500 rpm which I was able to hold with setting the idle screw. All is well with the cam, etc after that break-in procedure.
Keep the rpm up and use high zinc oil and break-in lube for about 20 minutes and it should be ok. You'll have to continue to use high zinc oil or some additive afterwards ( I use Comp Cams Break-in additive at each oil change, as they recommend, with Mobil One 20-50 oil)) or you may have problems later with the flat tappet cam and lifters, as most current oils don't have what the older flat tappets need to stay 'alive' (lots of threads about that problem on here).
Good luck.
walt
Keep the rpm up and use high zinc oil and break-in lube for about 20 minutes and it should be ok. You'll have to continue to use high zinc oil or some additive afterwards ( I use Comp Cams Break-in additive at each oil change, as they recommend, with Mobil One 20-50 oil)) or you may have problems later with the flat tappet cam and lifters, as most current oils don't have what the older flat tappets need to stay 'alive' (lots of threads about that problem on here).
Good luck.
walt
