always here different things from different people...anyone have good tips for small block break in? plus adjusting the rockers pre break in? thanks a million!!! "why would anyone go back in time to shove somebody?"
Been a few years, but I'd start w/the rockers backed off, whether solid or hydraulic lifters, you might try .020" clearance. Then, for hydraulic lifters, if you've got a spare valve cover, cut a lengthwise slot in it wide enough for a socket to fit the rockers, and adjust them down into mid travel (while idling) once she's warmed up a bit. (3/4 turn?) might ask Squirrel! As to break-in, the ring manufacturers had break-in tips on the packages, usually it involves getting a read on oil pressure, and then slowly accelerating up to a moderate rpm, and then backing off, repeated several times. If you've replaced cam and lifters, you DID use moly-sulfide or a break-in lube in their assembly?
Initial start should be 2K rpm for 20 minutes, or so, to get oil up on the cam. After that driving around town at varying speed.
There is an excellent article in this months Street Rodder magazine that covers this subject rather well.
That will work. I like to keep a timing light handy. If the timing is retarded the headers may cook. I have a squirl cage fan I like to blow through the radiator to keep it the engine temp under control. I also started running rotella 15w40 diesel oil in all my none roller engines. Jeff
Solids just adjust them as normal, Hyd I soak them in oil for a couple of days ,after installing them spin the pushrod in your fingers til the rocker tighens down on it ,then a half a turn more . The cut up valve cover works but makes a mess. Make sure timing is right on,carb is full (fill it thru bowl vent). You don't want to crank it long enough to wipe out the cam lube. Set harmonic balancer at correct timing point.5 or 6 before will work.On timing hook up your lite and rotate the distributor . The light will flash when it breaks.You should be within a couple of degrees then.
Pre-oil the engine with either buying the correct tool to do so with a drill or grind the can gear off an old distributor and drop it down and use a drill anyway . I like to go ahead and fill the block with water BEFORE I install the thermostat and water neck housing so I don't have to wait and have a dry block with cold water hitting it all of the sudden when the thermostat finally does open . It's hard for that thermostat to work off of steam and NOT WATER !!! For cam break-in you need to run about 1,800 to 2,000 RPM for about 15 to 20 minutes . As far as rings seating , it all depends on the type of ring and the finish the machine shop put on the cylinders ? Normal cross-hatch with cast rings , after my cam break-in period I will rap the engine up to around 4K or a little less and put my hand over the carb and hold it wide open to flood the cylinders with raw fuel just until it starts to die . I do this about 4 or 5 times and kill the engine and I DO NOT START it back up until the next day . Believe it or not but this will help the ring actually hold a square seat to the cylinder for the rest of the rings life if it's a normal cast iron ring . You can leave the breathers wide open on the valve covers and watch any blow-by just go away after about the 3rd or 4th flooding of the cylinders . You still have lubrication , you are just fattening up the mixture enough to thin the oil and its is cooling the cylinder as it helps the rings scrub and seat the walls . DO NOT try this with ceramic or chrome moly rings as it's all in the machine work if a ring is going to seat or not anyway . I'm just talking basic street re-builds with basic parts . NEVER leave rockers loose on a hyd. cam during break-in ! It will not only beat the shit out of the pushrods and rockers , the cam will wear like hell QUICKLY ! As somebody said , solid flat tappet or roller cams , adjust then just the way the cam specs call for . But I do suggest pre-oiling EVERY ENGINE before start up !
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