breaking in a cam

[BigBlockSam]

hey guys , i have a 1969 440 hp motor  short block with about 500 miles on it . now i've installed freshly done heads , new cam and gear . i have 10-40 oil with some zinc additive in it . is that good enough to break the cam in?   

[c00nhunterjoe]

I like to run lighter valve springs during breakin.

[Kern Dog]

That is ONE way to do it...
On a stock or even a moderate lift cam, you are fine using the same valvesprings that will stay with the engine. The real key for break in is to ensure that the engine starts immediately. Verify that you have spark and fuel before turning the key. Spray starting fluid/Ether down the carb and put the air cleaner back on, then start it and follow the Cam manufacturers instructions for time and RPMs. Most I've read call for a minimum of 20 minutes and a minimum of 2000 RPMs. If the engine starts to run hot, shut it down to let it cool off. The total break in time can be done in one session OR a few, just as long as the engine starts and runs quickly each time. The actual procedure involves time, rpms, oil being flung off of the rod bearings as the rods spin and heat. In most cases, a flat tappet cam desperately relies on the oil being squished out of the rod bearings as the engine spins. RPMs less than 2000 do not produce enough oil splash.
The new style EDM lifters are a great improvement, maybe you should look into them. The have a small hole in them on the foot of the lifter, allowing pressurized oil travelling through through the lifter galley to actually provide direct oiling from the lifter to the cam lobes. This single improvement should drastically reduce cam failures. Time will tell. I've ran them with 3 different cams and after many miles, they still look new. I doubt that they eliminate the need for the zinc additives, but they should help with longevity nonetheless.   

[RallyeMike]

It's still better not to run the engine hot and shut down. Here is the way to ensure the engine does not overheat through the whole break-in cycle:

1) Run water only.
2) Put a garden hose in the top of the radiator.
3) Open the petcock on the radiator to full open.
4) Adjust the spigot until water in = water out.
5) Start the engine and run the the break in cycle.
6) Check and adjust the water in vs. water out to make sure it does not get low. Also, its no fun having it top over and spray all over the place.

This works way better than relying on your engine fan or adding more external fans. The cold water is going in slow enough to not shock anything, but fast enough to keep the engine cool. The engine will come up to op temp and just stay there.

[BigBlockSam]

  thank you guys. a lot of great info . i think i got my answer