What does "breaking in a cam" actually mean

It means establishing a wear pattern between the lifters and cam so they last. Around 2000 RPM for 20-30 minutes gives "splash" from the bottom end to the surface between cam lobes and lifters. Keep an eye on the temp, and if it gets too high, idle it down, shut it off, let cool, and resume. Also, as said, there's been a reduction in the needed additives in most oils for different reasons. Racing oil has more of those things than most over the counter oils. I use Valvoline Racing oil, and it's available just about everywhere (Pep Boys, Autozone, etc). It wouldn't hurt if you add a bottle of cam breakin supplement. I get this at Home Mechanics in North Hollywood. Or use GM's EOS (engine oil supplement) from any GM dealership's parts dept. Don't use synthetic oil if the rings are new. They won't seat.

 

You may want to look at motorcycle-only oils too. They have had problems with the new oils in bikes also, mainly due th the gear clash in the trans, so the additive packages they use are different than the car oils. Those engines can run all day at 12K rpm (or higher).

 

was the engine run at the factory to break in the cam

 

I'm geting ready to put a new cam lifters & timing set in my 351w good stuff to know.
what would be a good cam for a cruiser???
Thanks
Frankie C
38 sled

 

Most likely replacing the cam in the not to distant future and trying it again.

 

I have had issues with flat cams on a couple engines due to the oil that the boss bought for the job. I learned about zddp and polar molecules. If you look at a machined or ground metal surface under a microscope it will look like a bunch of jagged peaks. The detergent in oil is a polar molecule as is zddp so when you are trying to break in a cam the two polar molecules will be trying to take the same place on the cam, so you want a non-detergent oil for break in. As mentioned in other posts the higher rpm is to keep the cam flooded with oil, and the reason to run it for about 20min. is to get it up to temp throughout the engine opening up the pores in the metal so that the zddp will bond into the surface creating an extreme pressure barrier. It is best to let the engine to cool completely and then run another heat cycle or two. This ensures a better molecular bond.

There are many break in specific oils. Joe Gibbs racing oil, Edelbrock break in oil, Amsoil to name a few. Be sure to use zddp and Comp Cams assembly lube or a comperable. Use a drill to pressureize the oil system so as not to run dry on start up. Proper break in will insure a long cam life. Jim

 

I build a lot of flat tappet race engines for my local short track buddies. .Local rules = no roller cams..
Here is the drill...
As everyone says above, lots of moly assembly lube...delo or rotella or valvoline all fleet diesel oil .. ( if it is designed for 24 to 1 compression it should be good for this !)
2000 to 2500 varying rpm for at least 20 min..
And last ..but most importantly. ..I add an extra quart of oil during cam run in...that way the crank counterweight is running in the oil and splashing extra lube on the cam...
After the run in I change the oil...cut the filter to check for bad stuff...
Using this method..it's been a very long time since I had any problems with flat tappet cams..


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wipe a lobe off the cam? backfiring?

 

Let me start by saying that when you "break in" a cam what you are doing is burnishing the cam lobes and mating them to the lifter that runs on that specific lobe. There was a time that it was called run in and still is by some of the older mechanics.

When you install a new cam or install new lifters on an old cam or refaced lifters on an old cam the process needs to be performed. It is more then just running at a higher RPM then usual, you also should slather the cam or the lifter faces or both with cam break in lube, it is a grease and lapping compound mixture. The higher RPM that the engine is being spun at should in fact vary during the run in period and there should be no load on the engine.

Manufacturers of camshafts suggest different times and RPMs for the break in period but generally the RPM is in the 2000 range and the time period is normally suggested from 30-40 minutes. if you listen and know what you are listening for you can hear a change in engine note when the cam is actually broken in and the actual time will vary from one camshaft to the next even on identical cams.

So I tried a multi quote and managed to mess it up, so to anser the querstion on engine run in in the '60s:
Now to answer your question as far back as the '50s that I know of engines were run in before you purchased the car. The oil was dumped and "break-in" oil was put in the engine that you needed to have changed @ 500-800 miles.

To answer your question on a cam that is not properly broken in sometimes it ends in cam failure or lifter failure and sometimes it does not. Cam break in is not an exact science and sometimes you just get lucky.

 

The cam saver lifters with a tiny flat spot on one side of the lifters really help with cam and lifter oiling to the lobes. Crower and Howard both sell them now. They're a little more money, but money well spent! I also use a good breakin oil like Brad Penn Break-In oil, and then use their 20-40 wt. Brad Penn after that.

 

I worked on the Ford FE hot test in the Dearborn engine plant in the mid 60's. The newly assembled engines were hooked up to quick connect cooling fittings and fired up. They were ran for only about 5 minutes to check for leaks, and set the timing. Then they went down the line ready to drop in a car (or truck)