Cam break in question

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Cam break in question

Post by thepossumface on Fri Aug 30, 2013 11:06 pm

okay sense this is my first cam swap ive done, what all do i need to do to break it in correctly and not destroy anything.
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Re: Cam break in question

Post by Sleddogg on Sat Aug 31, 2013 3:23 am

If you installed a hydraulic flat tappet camshaft, then this is a procedure I have used with good results for many years.

I prelube the engine with a drill until I can see oil flowing from the pushrods onto the rocker arms.  Manually turn the engine to #1 TDC,  make sure you have gas squirting from the accelerator pump in the carb, if not pour a little down the carb with the throttle open.  Make sure all your vacuum hoses are connected and hit the key.  When the motor fires up, increase RPM to about 2000 RPM (after making sure you have good oil pressure)  I like to adjust the timing until the engine runs at the highest RPM at the set throttle opening, then retard it just a tad and lock it down, this makes sure it runs cool and does not detonate.  Then just keep the RPM's between 1800 and 2000 varying slightly, but don't let it idle for any length of time.  After about 20 minutes, let ithe RPM's drop to idle and shut it down.

Change your oil.

Make sure you use a good quality cam break in lube, or break in oil that is specifically meant for hydraulic flat tappet cams for break in.  The motor oil they sell off the shelf these days doesn't have enough ZDDP (zinc dialkyldithiophosphate) to support cam break in and you will most likely wipe a lobe.  I make sure I use oil that has high ZDDP levels or and additive at every oil change.   If you put in a roller cam, you don't have to worry about it.

Also, if they motor fails to fire up fairly quickly, don't just keep on cranking it, you will lost most of your moly lube on the cam lobes.  Find out why it isn't touching off, and fix that..then break in your cam.  

Have fun Smile


Last edited by Sleddogg on Sat Aug 31, 2013 6:08 pm; edited 1 time in total
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Re: Cam break in question

Post by pila on Sat Aug 31, 2013 12:29 pm

What Sleddogg said, and...DON'T let it idle ! Idling will trash the lobes on a new cam, in just a few minutes.
I always cut the oil filter apart & check for metal in the filter media ( paper !) after the the break-in run.

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Re: Cam break in question

Post by thepossumface on Sat Aug 31, 2013 12:51 pm

so i hold the peddle down for 20 min and not let it idle or adjust the screw so it revs at 2,000 spms and let it run at that correct?
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Re: Cam break in question

Post by Sleddogg on Sat Aug 31, 2013 12:55 pm

Either way, it helps to use the idle screw to hold it at 2k just so you can do other things like set the timing, check your coolant level, check oil pressure, etc etc.  If you have a buddy and a tach, you can have them man the pedal while you do these things.  I usually just try to manually work the throttle between 1800 and 2000 rpm and have someone else man a fire extinguisher and keep an eye on those things for me if possible.
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Re: Cam break in question

Post by pila on Sat Aug 31, 2013 7:19 pm

YUP !Very Happy 

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Re: Cam break in question

Post by bracketchev1221 on Wed Sep 04, 2013 7:00 am

It helps to have a big fan in front of the car to blow as much cooling air over it as you can. I agree with getting it running and getting the timing set. Retarded timing will make it get hot fast and make the exhaust glow.
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Re: Cam break in question

Post by Dinomyte on Wed Sep 04, 2013 10:22 am

The guys at the machine shop suggested I pull all the plugs, and the ignition wire, then crank the motor. Said and it did turn over reall easy, did it for 5 or six 15 second intervals, no need to remove the distrubutor this way.
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Re: Cam break in question

Post by Joe73 on Wed Sep 04, 2013 1:19 pm

Yes, it will turn over real easy without the plugs. But you will still have metal on metal contact until the oil pressure gets up. Especially on the top end of the engine. I wouldnt do what the shop says. I say prime it with a drill, then start her up. Everything will be pressurized and ready to lubricate.
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Re: Cam break in question

Post by bracketchev1221 on Thu Sep 05, 2013 7:01 am

Joe73 wrote:Yes, it will turn over real easy without the plugs.  But you will still have metal on metal contact until the oil pressure gets up.  Especially on the top end of the engine.  I wouldnt do what the shop says.  I say prime it with a drill, then start her up.  Everything will be pressurized and ready to lubricate.
I agree, I never liked doing this. If the distributor is out, prime it. Every year before I start the car, I change the oil and pour it over the valvetrain, and let it run down over the cam and then over the crank. Pour it down the front so it drains through the timing cover, and then let the rest run the length of the engine to the rear. Been doing this with 300 psi on the seat springs and a .788 lift roller cam for years and no failures.
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Re: Cam break in question

Post by pila on Thu Sep 05, 2013 7:50 am

Running a roller cam solves a lot of problems with engines that are stored during winter months etc, like no dry starts on flat tappets etc.

Using non-detergent oil for storage helps, with flat tappets. It doesn't run off of the parts like detergent oil does, & leaves more film there, after running the engine before storage.
Of course it's another oil change in springtime, back to whatever is normally used.

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Re: Cam break in question

Post by bracketchev1221 on Thu Sep 05, 2013 11:19 am

pila wrote:Running a roller cam solves a lot of problems with engines that are stored during winter months etc, like no dry starts on flat tappets etc.

 
I disagree. One of the biggest failure causes is when the oil runs off the needle bearings of a roller lifter when it sits and you start it with no oil. It is more of an issue with the higher spring pressures required with a roller cam. Roller or flat tappet they need oil.
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Re: Cam break in question

Post by JB2wheeler on Thu Sep 05, 2013 12:31 pm

When my car with roller cam sits for a long time I do something that EVERYBODY tells me is wrong. I do not engage the choke and I crank the engine until I get oil pressure and then I engage the choke and it cranks right up. Is everybody right? JB
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Re: Cam break in question

Post by pila on Thu Sep 05, 2013 2:14 pm

I understand what Ray is talking about, on the needle bearings. And I was thinking of mostly stock parts too.....

I use a pre-oiler pump on my boat engine after winter storage. Removing that engine for repair etc would be a real hassle..

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