I'm a couple days from being able to fire up my 350 swap in my jeep. I've read alot of different methods for breaking in an engine, from babying it all the way to breaking in the cam and then running it like you stole it. What method do you all use? It's a mostly stock 350 chevy engine. I believe it's a 1971 block and heads.

 

I would run it like you stole it. I believe that method works.

 

Do a cam break in. Then drive it at varying speeds and acceleration under 50MPH for 50-100 miles. After that, push it hard for 100 miles. THen drive it how ever you like.

 

i was always told to break it in like you were gona drive it... so if your gona baby it then baby it n if your gona run it hard then run it hard just my .02

 

Yup. I drive my truck hard. I break my truck in hard.

 

There are several different schools of thought on this. Someone posted an article on here a while back to break it in hard right from the start so the rings will seat sooner and then there's the powder puff theory as well. I always ran a rebuild at about 2500 rpm for 30 minutes to break in the cam first. After that, wait for the oil pressure to come up and mash the motor.

 

How about oil changes? I know after cam break in, but i've read where some have changed it every 100 miles for the first 500 miles. Seems excessive to me.

 

Break it in like you are going to drive it.

 

The oil companies will like you.
Way too excessive for me.

 

never heard of changing the oil that often. i probably would do it at 500 or so...

 

Change it after 20 minutes... Then again in 500 miles.


I've always heard run it like you stole it.

 

Thanks for the info guys. I think i'm going to break the cam in, change the oil, then run it hard for 500 and change the oil again. If it's gunna have a problem, I'd rather it have it within 500 miles than in 3000 miles. Thanks again.

 

break in the cam in the first 30 minutes by varying rpm's between idle & 3000-3500 rpm , start it & run for abut 10 minutes varing the rpm, shut it down, let it cool down, then start it & repeat for about 20 minutes. that should take care of the cam. keep an eye on oil pressure & water temp, if oil pressure drops dramatically or temp gets over 220 shut it down & let it cool. once this is done change the oil & drive it. don't over baby it or hammer on it, set the idle a little high for the break-in period, around 1000-1200 rpm, long highway drives work good, varing load & rpm, the idea is to get everything evenly warmed up, load & unload the engine, up & down hills. don't over rev (try to limit rpm to around 3500) don't overly lug the engine either (you don't really have to worry about this with an auto, but with a manual, down shift a little early, to keep the rpms up around 12-1500) the reason for this is fresh rings & newly honed cylinders have lots of drag, & over reving, or excessive lugging can create pressures that can crack them(the rings), leading to immediate failure, or oil consumtion later. after 500 miles change the oil again. you can pretty much assume it's broken in at that point. good luck

 

I wish I could find this article an engine builder wrote about breaking in engines... he did motorcycle engines and he basically had a method of running the snot out of them at varied loads to initially break them in.


He had photos of engines broke in in different ways and was saying the ones using his method of running them hard made more power and lasted longer... And it was evident by looking at the photos if you know much about engines.

Granted these were racing engines that don't have a long life... So who knows.

 

If its going to break i want it to break while im in the mood for fixing things. Might as well find out if it was done right quickly.

Beat on it from the get-go.