Rebuild Break-in

[speedy]

First time on the forum.  Great site!!  Got a question about breaking in a freshly rebuilt 350.  I've read tons of articles about breaking in engines and opinions vary widely.  About the only common ground I've found is no synthetics.  Basically they're so good they PREVENT ring seating during break in.  SO...What's your advice?

[Captkaos]

Break-in the engine or the camshaft?  I would follow the cam manufactures specs on how to break it in, but on the engine I use non-detergent oil and change it after 600 miles.

[speedy]

I guess the answer would be both the cam and the engine.

Dog on it.  Don't dog on it.  2000rpm for 20mins at a time...No don't do THAT!!! 

[Captkaos]

Generally to break in the cam you run it between 1500 to 2000 rpms varying for 15 minutes.  Once that is done and you verify the valves are adjusted, the cam should be good to go.  Once that is done I drive it like I normally do.

[speedy]

So after the cam break-in, is there anything I shouldn't do? 

[Captkaos]

It really depends on who you ask.  Think of it this way, when you go and buy a new Corvette from the dealership with 0 miles on it, how would you drive it?  Me, I would be thrashing it on the way out of the parking lot.  I did my last motors that same way.  Once I hit about 600 miles I changed the oil to synthetic and that was it.

Some people say you should keep it below 60 mph, no jackrabbit starts etc...

[VileZambonie]

1st, make sure you fill the engine block with coolant then put in the T-stat and finish filling the radiator. Use a spill free funnel since the coolant level will go up and down. It's a must have tool. http://www.sjdiscounttools.com/lis22150.html

Make sure you primed the oil pump and used a good primer http://www.carpartswholesale.com/products/?ys=1973&ye=1973&make_t=chevrolet&model_t=suburban&pn=oil_pump_primer&ci=A1165930884W457eb1843f043&kw=73+Chevrolet+Suburban+TransDapt+Oil+Pump+Primer

Have a timing light ready because if you break in the engine with over advanced or severly retarded timing you can cause some serious damage.

On initial start-up new cam and lifters especially hold the engine RPM's over 2200RPM and very the speed. After you break in the cam and the valve train change the oil and filter.

On your first test drive do not be afraid to drive it like normal but it is important that you are able to accelerate to wide open throttle in order to allow the rings to seat. Many folks beleive this is incorrect or bad but beleive me your ring manufacturers will agree. Make your test run at 30 MPH and then accelerate at WOT to 50 MPH and repeat this at least 10 times. That's all you have to do. Then drive it like it's yours

[1976Scottsdale]

Get it to run and stay running, about 2000 RPM's for 15-20 minutes, then set it to about a 700 or 750 idle, cut the top off of an old valve cover, put it on your engine, then start it and loosen each rocker until it ticks, then tighten till it stops and go about 1/4 to 1/2 turn more, then  do the other side.  Make sure you fill the oil back up and let it run for a bit to burn off the oil you just bathed the engine in.  Then go drive it easy for about 50 to 100 miles.  Dump the oil and filter and fill up the new filter when you put it on, then drive it real easy for about 500 miles and change oil again.  Then Drive normal, no hard acceleration, until 3500 miles, then you are good to go.  Oh yeah, keep checkin' that oil.  These engines EAT that stuff when they seal up... they won't puff one sorry blue cloud, but they will eat 1/2 to 2 quarts of oil while sealing up.

[VileZambonie]

Adjusting the rockers that way is not only inadvisable but has little to do with breaking in the engine. A decent engine builder will have valve lash worked out way ahead of starting it up.

[JJSZABO]

My crate engine instructions say to NOT adjust the valves during or after breakin.  I have a 350 ATK crate engine - still havn't fired it up yet.

Jeff

[Captkaos]

As Vile pointed out, you should already have the lash on the lifters set before even attempting to break the cam in.

On crate motors this is the same theory.  All you need to do is break in the cam and drive it.

[DirtyLittleSecret]

So many different theories on how to do this...especially when there's a warranty involved.
Me, I drive it like I stole it.
there's a warranty involved.