What's the proper way to 'beak-in' a Cam? ...or

[raven]

Is there any way to sto mine from disintegrating?
It's been a week since the last time I adjusted the lash and it's sounding like it's due to be adjusted again...
I'm almost to the point of replacing this 'new' cam, but the only intrepidation I have about that is the proper break-in procedure, what is the proper procedure?
Should I also buy new lifters?
The ones in the motor now have only about 600 miles in them...
r

[RileyRacing]

My Mopar engines manual says to hald it above 2000 for at least 20 minutes, then gradually bring it down. Never let it idle for a long time with a NEW cam...

Jay

[Fat Hack]

ALWAYS put new lifters on a new cam...ALWAYS!!!

As for break-in, I adjust the lash cold (solid or hyraulic, you can get them real close with the engine off). Roll each cylinder to the point where both valves are closed and make your adjustment. For hydraulics, I set 'em so you can still spin the pushrod with two fingers, but so that it takes a little effort to do so. For solids, use the cold lash setting with a feeler gauge.

Fire the engine up and get it to about 1800 rpm. You can crank up the idle speed screw to hold it there. Watch for problems such as leaks and overheating...having two people on hand is a real plus here. If you encounter any trouble, SHUT THE ENGINE DOWN AND FIX IT, then continue.

Work the throttle gently, running the engine up to about 2800 rpm and back down to 1800. Do this slowly, don't 'snap' the throttle. You can let it run for a minute or two at various rpm levels between 1800 and 2800 if you wish, but I like to work it up and back slowly.

Do this for 20 minutes or slightly more if you wish.

Then, turn the idle speed screw back down to the normal setting and set the valve adjustments.

(I covered all of this in a cam installation post that's probably about 1200 pages down by now...I'll see if I can find it!)

[Paul]

a new cam gets new lifters.

600 miles is not new, 0 miles is new.

dump a bunch of assembly lube all over it before you put the valley cover/intake manifold on.

start the motor and bring the rpm's up to 15 hundred or so and run it for 15 minutes.

have your oil pressure and water temp gauges hooked up.

pretty basic stuff, here..

Paul

[Fat Hack]

Here's more:

http://www.jalopyjournal.com/ubbthreads/showflat.php?Cat=&Board=UBB1&Number=165254&Forum=U BB1&Words=poster%20board&Match=Entire%20Phrase&Sea rchpage=0&Limit=25&Old=allposts&Main=165254&Search =true#Post165254

[raven]

Thanks Fat Hack.
That's exactly what I was looking for.
I guess that I screwed the cam so now I get to replace it...
r

[FWilliams]

i pretty much do the same as FatHack with the exception that i do like to " blip the throttle" up to about 3500 to 4000, { just ask SAMIYAM http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif} depending on the build. what you are doing is keeping the cam bathed in oil, you want to keep as much oil slinging around as you possibly can. the biggest problems that i run into , especially on performance builds, is they want to here the idle. Soon after the break in they have all there buddys over listening to the thing idle, boom flat cam. remember you have only 20 minutes or so on the engine, get some miles on it before the idle sessions, also guys using windage trays, i like to install them after the breakin, it is more hassle, but they keep huge amounts of oil from the cam.

RACEFAB

[plan9]

racefab and fathack nailed it... i have ground down 3 cams, but not from cheesing out on the idle http://www.jalopyjournal.com/ubbthreads/images/graemlins/smile.gif

question: if you run stiff springs, is it wise to swap for less stiff ones for cam break-in?

[Lionheart]

The first 20-30 min. are critical to keep the rpm up so the lifters 'spin' in their bore and mate with the cam. At low rpm, this will not happen, and you ruin the cam.

[Fat Hack]

Good point about the windage tray, Racefab...you definately WANT oil moving around as the cam is breaking in!!

Plan9...some guys DO use weaker "break in springs" on some extreme cams. This is is good if you don't over-rev the engine with the weaker springs installed, and also be sure to cheack that they don't bind at all with increased lift. Use caution when running weaker springs, but you CAN get away with it so long as you cover your bases.

[Fat Hack]

I like to be under the hood while breaking in the cam, so having another set of eyes to watch gauges inside the car is a good thing. However, I do have a couple tricks I use when doing it solo.

Take an old tach and make a magnetic base for it. Then attatch alligator clips to the three wires. This makes a great temporary tach that can easily be connected and placed within view under the hood where you can watch your rpm.

A home-made "idiot light" for oil pressure temporarily placed within view is a good idea if you don't have a diagnostic gauge you can hook up to watch on the engine as you break in the cam. I step over and peek in the window every couple of minutes to check the temp gauge as well. Keep a sharp eye open for any problems...you CAN stop the process short an re-start if you need to fix a leak or address another issue before you're done with the break-in process.

[BELLM]

Just pulled a Comp Magnum 270 out of box tonite to put in SBC. Instructions say 2000 rpm 30 minutes, suggest remove inner valve springs, etc.. Different strokes for different folks. racefab & others speak from experience. Dont waste a new cam to used lifters, they are cheap.

[Curly]

Well guys this seems to be worthy of a Tech-o-matic vote. I cast my vote anyone care to second that motion?

[TagMan]

FWIW, my Son-in-Law has been a cam design Engineer for G.M. (now Delphi Automotive) for 24+ years. He's tested cam designs in the field from the Arizona deserts to the northern reaches of Canada, as well as the labs, so I gotta believe he knows what he's talking about. He also has been a drag racer for many years. He told me that the absolute best way to break in a cam, is to pre-lube it in assembly, spin the oil pump manually before starting the engine to make sure the oil pressure builds OK, and tuning the car so it will start immediately, ideally, within one or two flywheel turns, then bringing the RPM's up to 2000 and running it there for 20 minutes, without varying the engine speed. Excessive cranking an engine before it starts can do a lot of initial damage to the cam & follower surfaces. They've started thousands of engines and have found that 2000 RPM is the best load for break-in. I've followed his advice and have never had a problem.

[Impala53]

I didn't become a car nut til about 5 yrs. ago. Hate to admit, I'd never heard about cam break-in til someone told me I was lucky I didn't flatten my cam on startup. What? I adjusted the valves at probably 1200 rpm. New cam, old lifters! Yikes, sounds like I got lucky alright. Only thing I did right was ran oil pump a couple mins. before starting the old 305.
So what are the symptoms of a flattened cam?