An abridged break-in method from the defunct Crane Cams, any brand of cam break-in lube from a reputable cam manufacturer:

Due to the EPA's mandate for zinc removal from most motor oils, proper flat tappet camshaft break-in procedure is more critical than ever before. As a point of interest, the most critical time in the life of a flat tappet camshaft is the first 20 minutes of “break-in” during which the bottoms of the tappets “mate-in” with the cam lobes. There are some oils with additive packages that are better for camshaft “break-in”. These include, but are not limited to: Brad Penn or Joe Gibbs racing or a “race only” petroleum- based oil and include Crane Cams Part # 99003-1 Super Lube” additive. Do not use API rated “SL” or “SM” oil. We do not recommend the use of synthetic oils for “break-in”.

Proper flat tappet camshaft break-in starts with the cam installation
and includes the following steps:
Before installing the camshaft and lifters, wash them thoroughly in clean mineral spirits to remove the rust preventative that is placed on the cam before shipping. NOTE: As a “rule of thumb”, always thoroughly clean
any part before installing it in an engine. Never “assume” that the parts are cleaned before packaging. During shipping, packaging material can rub into the component surface and must be removed! With the supplied moly paste lube, coat the bottom of the lifters, cam lobes and distributor gear. Use Crane Cams assembly lube Part # 99008-1 on all other surfaces and components. Set your valve lash. Try to minimize the number of times that you rotate the engine, as this can displace the moly paste from the lobes and lifters. If possible prime the oiling system. When priming, rotate the engine at least one complete revolution to assure oil gets to all valve train components. Valve covers should be off to assure that all rockers are oiling. Preset the ignition timing to start the engine at a fast idle. It is important that the static ignition timing is as close as possible and if the engine has a carburetor, it should be filled with fuel. The engine needs to start quickly without excessive cranking to insure immediate lubrication to the cam lobes. Start the engine and immediately bring to 3,000 rpm. Timing should be adjusted, as closely as possible, to reduce excessive heat or load during break-in. Get the engine running fairly smoothly and vary the engine speed from 1500-3000 RPM in a slow, to moderate, acceleration/deceleration cycle. During this time, be sure to check for any leaks and check out any unusual noises. If something doesn't sound right, shut the engine off and check out the source of the noise. Upon restart, resume the high idle speed cycling. Continue the varying “break-in” speed for 20 - 30 minutes. This is necessary to provide proper lifter rotation to properly mate each lifter to its lobe. Should the engine need to be shut down for any reason, upon re-start it should be immediately brought back to 3000 rpm and the break-in continued for a total run time of 20 - 30 minutes. Let the engine cool, and then drain the crankcase and properly dispose of the oil and oil filter. Refill the crankcase with a premium petroleum-based oil, not a synthetic oil. At this point the initial “break-in” is complete. You can drive the vehicle in your normal manner. We recommend changing the oil and filter after 500 miles. You might want to put another 5000 miles on the cam before switching to a synthetic, if that is your preference.

ADDITIONAL INFORMATION:
Spring Pressures: For extended camshaft life, flat-tappet cams should not be run with more than the
recommended open valve spring pressure. Racing applications will often need to run more spring pressure at
the expense of reduced camshaft life. In order to “break-in” a camshaft with high open pressures, the inner
springs should be removed to reduce “break-in” load. The inner springs can then be reinstalled after initial
“break-in” is complete.
Lifter Rotation: Flat tappet cams have the lobes ground on a slight taper and
the lifter appears to sit offset from the lobe centerline. This will induce a rotation of the lifter on the lobe. This rotation draws oil to the mating surface between the lifter and the lobe. If it is possible to view the pushrods
during “break-in”, they should be spinning as an indication that the lifter is spinning. If you don't see a pushrod spinning, immediately stop the engine and find the cause. Never use old flat tappet lifters on a new cam. On flat tappet cams, the lobes and lifter bottoms mate together and if the lifters are removed from the engine, they must go back on the same lobe from which they were removed.


I wouldn't go less than 2000rpm during cam break-in. 90% of what Crane sold was for American V8's which have a lot more oil around the camshaft area than the B20.

Ignition timing: set to 10º static, bring the engine up to 2500rpm, then advance the timing another 15º to help the engine run cooler during break-in. As soon as you have jacked up the timing, start cycling the engine from 2000 up to 3000 & back to 2000 again as per Crane's instruction. After you shut it down, set the timing back to 10º static.

Cam timing: 99% of pushrod engines like 4º of advance, no less.

Why is this whole page about cam break-in? Because that is the only thing that needs breaking in in a flat tappet engine. The only thing to avoid in the first 500 miles is excess idle + try not to baby it to much.

Make sure you use a good diesel engine oil & a zinc additive.



--
Three 164's, Two 144's, One 142 & a partridge in a pear tree.