Thread: Breaking in rebuilt 454?

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I mostly worried about my cam during the break in process. My engine builder said he is going to install some weaker springs for me to use during the first half hour of run time. Then install the recommended ones. I have never changed valve springs before but I have an idea of how to do it and some buddies that done it before. The engine builder said I don't really have to go that route but he recomends it. the cam is a 268xe. Have you guys ever had to do it this way. I was reading a article on compcams.com they said just to use a good oil like Rotella. Could someone just explain how this cam gets broke in. Does it just get harder as it breaks in or what. Thanks

I've never done the weaker spring routine, but I have seen guys on here recommend it before, so I guess it does have some merit, especially if you are running some stiff ones.

To answer your question about the cam and lifters, any moving part has to wear in to the same relative shape as the part rubbing against it. Piston rings do it, bearings do it, and cams and lifters do it. What you want to do is minimize scoring during this wear in period.

I always prelube engines before fire up. You can buy an inexpensive preluber that you hook up to a strong 1/2 inch electric drill and spin the oil pump so that oil is distributed throughout the entire engine BEFORE you try to start it. You can also modify an old distributor to do this, by removing the gear from the bottom, and hooking your drill to the shaft where the rotor normally goes.

The idea is to turn the oil pump in the same direction the distributor normally spins until you feel the drill slow down from the load on the pump, then keep it going for a couple minutes more to pump oil to every bearing, lifter, etc in the engine. Then, when you reinstall the regular distributor, have everything set perfectly so the engine fires as soon as possible, then bring the rpms up to about 2000-2500 and keep it there for 15 to 20 minutes, to let everything break in to all the other parts.

Then change your oil and filter immediately, and you are ready for the first test drive.

Others on here will have other suggestions as to this procedure, but this one has always worked for me. But, like everything else, there is more than one way to do something.

Don

I don't know the details of your cam and valve springs and don't have time to look them up, but if they are double or triple springs/dampers then running softer valve springs for the first start-up is commonly done, and is in fact a smart play. Typically the cam lobes and lifter faces are also lubed with moly lube for this purpose.

The main thing though is the prime before the intial start-up. Be sure to do that. While doing it turn the engine over a couple revolutions by hand, not the starter, while the drill is running.

Regards, Kitz

I just broke my cam in on my engine stand. See other post. It makes it so much easier. I primed mine as well with an old distributor housing machined down. I also had an oil press. gauge hooked up while I was priming it as well. The most imortant I feel is getting it to fire and keep it going for 20min at 2000 or so. Mine fired on the 1st revolution.
T.J.

have built many big blocks some of the block from gm had bad lifter bores they were off and would cause the cam to go out. so the break with light spring may help but if the block is off in the lifter bore this may not help. some lifters are better than others to if you tell me what is you seat psi is ? if it is 135 psi i would run it with the spring you have . i try to run all the big blocks i build with roller cams in them .but there are somethings that will help . get it to fire up no cranking.and run it at 2000 rpms. 1/2 hour. if soild cam you can sand the lifter feet with 600 wet dry sand paper or use the hy lube lifters they have a EDM hole thru the foot of the lifter so oil will be were you need it and helps at low rpms so oil will be on the cam lobe. i like the hard face lifers .this lifter has a hard lifter foot that is put on the lifter body . primeing the engine you should all ways do but you need to use a old dist body so oil will go thru the oil galley the dist will plug the big hole so oil will get to the top end and may help if it a hyd lifter engine have light oil in them so this still will help . molly work ok but you have to put it only on the the lobe and lifter foot not on the side of the lifters i use oil here. make sure you can turn them in the bores before you lube them. if this was done by your engine builder then you can not do much now . so if he wants to run it in with light springs in it and brake it in for you you may want to pay him to do this so the cam may have a chance. to brake in ?this is why i run roller cams after doing all this there is still a chance it will whipe with a soild cam

Dont' use synthetic oil!