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Discussion Starter #1
hey yall,
i've just rebuilt my 289 for my 66 and i've heard 2 different ways to break it in one is driving at no higher than 2000 rpm for 3000 miles or let the engine warm up and then heavy acceleration for short periods of time. are either of these the right way to do it or is there a better way? any advice would help. thanks
 

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Hopefully you have coated the cam lobes with the cam lube supplied by the manufacturer, it is absolutely critical to proper camshaft break-in. Pre-lube the engine by running the oil pump with a drill, fill the carb with fuel and make sure the timing is roughed in close enough to fire easily(keep the coolant level up). As soon as the engine starts bring it up to 2000-2500 RPM and keep it varying between those RPM's for about 20 minutes, the cam gets its lubrication from oil thrown off the crankshaft and that rpm will keep it lubed while the lifters mate in with the lobes. Some people like to dribble some ATF into the carb while you are mating the cam/lifters to help lube the piston rings, I have not done that. I then shut the motor off and check all fluids, bolts etc. to make sure all is tight and not leaking. Change oil and filter after about 500-800 miles. Watch engine temperature closely, it will run warm, but it should not run HOT.
The heavy acceleration is meant to help the rings seat in, if the hone finish was matched to the type of rings, you will not need to do that(kinda old school!!). Good Luck!!!
 

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Good advice! The 2000+ RPM should be maintained for 20 minutes. That breaks in the cam. Not needed for roller lifters btw.

The ATF should NOT be used unless you have cast rings and you do not.

After this you MUST let the motor rest for 24 hours. Do not start it.

I change the oil and filter at this point.

Run new oil for about 800 to 1000 miles and vary your speed. Stay below 4000rpm and try not to stay at the same RPM for extended periods.

Change oil to your choice of synthetic. Mobil 1 is most popular. Amsoil is the best money can buy.

Done! :eyepoppin
 

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Discussion Starter #4
well thank yall very much for the advice i'll be sure to do so and pass it on to them others that told me them other ways. thanks again
 

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The 2 methods I've always heard of are similar to what's been said

(after you break in the cam and change the oil)

1) Use the method straight out of the new car manuals...no extended high speed (60+) driving, vary your speed...all for 500miles

2) The old school method dragracer's: after the oil change, make sure everything is OK, and go flog it. A few short wide open blasts, then drive normally, WOT blasts again, flog it harder, then change the oil again. Some even have said to max out the RPMs and hold it for a few seconds. Remember though, if you do this, be careful not to flog it TOO hard. :D They contend that this is the only way to get the fresh motor to make the most power and act the best that it can, and get the rings to seat the best.

Something says to me that #2 is the logical choice...you'll be driving this thing with enthusiam, so why not break it in that way?
 

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2) The old school method dragracer's: after the oil change, make sure everything is OK, and go flog it. A few short wide open blasts, then drive normally, WOT blasts again, flog it harder, then change the oil again. Some even have said to max out the RPMs and hold it for a few seconds. Remember though, if you do this, be careful not to flog it TOO hard. They contend that this is the only way to get the fresh motor to make the most power and act the best that it can, and get the rings to seat the best.
I AM an 'old school dragracer'!

Once you understand the metalurgy behind the breakin procedure you'll understand the complete folly of that procedure for a street driven motor that must survive thousands of miles and not a few times at full throttle.

The short story is...All of the bearing surfaces have valleys and ridges no matter how the surfaces are machined. The breakin procedure wears those valleys and ridges in a rapid manor and developes the running clearances for the life of the motor. Run the motor hard at the onset of new bearings and heat anneals the ridges preventing the neccessary wear. You will get excessive oil usage and premature wear. You might not notice for a few thousand miles, but use your common sense. The motor MUST have clearances within a certain range ro keep oil pressure and compression. That is the definition of the procedure.

That said, today's designs are indeed manfactured better than motors of old and the parts are of higher quality. Lubricants are 500% better than even a few years ago! However use some common sense walk softly before using that big stick!.... :smoke:
 
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