Thread: break in.

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i just rebuilt a small block 355 it has a edelbrock performer rpm intake and carb(750) it has a comp cam and shaved heads it also has heddman headers and roller rockers. How should i break it in till i can really romp on it and how long should it take?

15 to 20 minutes at 2000 RPM should do it. Change the oil and filter, then give her hell.

Keith...

If it is a flat tappet cam I would add a can of GM EOS oil additive for the break in.

Originally Posted by Blackroc

If it is a flat tappet cam I would add a can of GM EOS oil additive for the break in.

And do NOT use synthetic oil for break-in.

If you have a high lift flat tappet cam with heavy/multiple springs you may want to consider the first 20 minutes with stock springs only to reduce risk of wiping your cam early on.

I personally wouldn't give her hell after only 20 minutes. I would avoid full throttle runs and constant rpm driving for the first 500 miles after which I would again change the oil. Then I would give her hell. BTW if your heads are aluminum you will need to recheck torque after the first 20 minute run.

Kitz

GM's oil suppliment isn't that important if you stick with the stock springs. There is no proven reason not to run synthetic in a break-in motor except that you will be changing your oil early and it's a waste of money to do for that reason. Do keep the rpms up, don't lug the engine while driving, no prolonged high rpm or high power output, and don't maintain speed. You should burn some oil within the first thousand miles (less than 1 quart). Afterwards, your oil consumption will stop and your motor is broken in. I ran Castrol GTX 10w30 for my break-in. Changed the oil at 1200 miles, 4500 miles, and now I'm at 9000 miles. If you look at the API grade on the back of the oil, most oils are SM grade. SL grade would be preffered for flat tappet motors because of its high zinc content. Some of the heavy duty oils such as Chevron Delo 400, Shell Rotella, and Mobil Delvac stll have the SL rating, for now.

In my humble opinion, GM Engine Oil Supplement is absolutely essential to properly break in a new cam. It isn't that costly, so why would you risk not using it?

Wash the lifter faces and the entire cam with solvent to remove the rust preventative that is applied at the factory. Then wash the lifter faces and the entire cam with a strong detergent and hot water. Dry thoroughly with wife or girlfriends blow dryer. Massage the black molybdenum paste that is supplied with the cam into the lobes and lifter faces. And I mean spend a little time and MASSAGE the lube into the pores of the metal on the lobes. Then smear the rest of it onto the cam journals and install the cam.

Prime the oil system, have a fully charged battery installed, have the timing set properly and have a primed carb set ready to run. If the motor fails to fire on the first couple of revolutions, STOP. Find out why it isn't firing. Does it need to be choked or what? DO NOT GRIND ON THE STARTER. THE MOTOR MUST FIRE IMMEDIATELY TO ALLOW OIL TO SLING ONTO THE CAM FROM THE CRANKSHAFT. OTHERWISE YOU WILL WIPE OUT ONE OR MORE CAM LOBES.

Do not use high performance springs to break in the cam. Use stock items and swap them out after the initial 500 mile break in period.

The longer I've used roller cams . . . the more I like them . . .

I agree the roller cam are the way to go if you can afford it or need it. Takes a bunch or worry out of firing up a new engine.

i just got done adjusting my valves for the second time and using two methods and something is still tappin on the driver side. do i just need to adjust my valves with the covers off?