Proper procedure for new engine break-in

I picked up my truck today from the dealer. They put in a new engine. Runs great now, no misfiring anymore.lol Anyway, in my haste, I forgot to ask if I needed to follow any break-in procedure.

Any recommendations as to how to break-in a new engine? It's the GM Goodwrench 350 crate motor. I'll probably give the dealer a call tomorrow anyway, but I just wanted to know how some of y'all do the engine break-in, or if you even do it.

I've heard keep it under 3000 rpm, vary your speed lots, keep it under 50, and change your oil within the first 500 miles.

If it has a non-roller cam shaft (L31 Vortec, 96 - 00 has a roller cam shaft), then the engine should be run for 20 minutes above 2000 RPM for the lifters to break in properly. This should have already been done by the shop that installed then engine.

Personally I take it easy for the first 500 to 1000 miles but I don't think you have to keep it under 3000 RPM. The rings should be seated by now.

I also like to cut open the oil filter on the first oil change to look for any signs of metal in the filter.

//2000CAYukon

What I've always been told and have done is take it to a deserted road and go ten miles an hour then floor it to fifty miles per hour, gently slow back down to 10 and repeat ten times. This will help seat your rings.

.... take it easy for the first 500 to 1000 miles ....

"taking it easy is the WORST plan if you want the rings to seat. You have to operate under load to generate enough combustion heat and pressure to properly seat the rings. One way to simulate load is to repeatedly accelerate from 25-60 MPH. The rings and cylinder walls need heat and pressure wear-in. Tking it easy allows a glaze to build up on the cylinder walls and then the rings will never seat.
http://mototuneusa.com/break_in_secrets.htm

"taking it easy is the WORST plan if you want the rings to seat. You have to operate under load to generate enough combustion heat and pressure to properly seat the rings. One way to simulate load is to repeatedly accelerate from 25-60 MPH. The rings and cylinder walls need heat and pressure wear-in. Tking it easy allows a glaze to build up on the cylinder walls and then the rings will never seat.
http://mototuneusa.com/break_in_secrets.htm

You are entitled to your opinion. The website you posted is for motorcycle engines.

This is a quote for a GM High Tech Performance Article.

So, how to go about this? We spoke to Mark Chacon, Lunati's East Coast Regional Rep., about his thoughts on this issue. "As motors are breaking in, and in regards to piston ring seal, they want a constantly changing engine rpm environment. This is why city driving is generally the optimal condition for any motor break-in. The worst thing that you can do with a new engine is to put it together, fire it up, and then head down the interstate with the cruise control on. While a little bit of freeway driving is OK, certainly for the first 500 to 1,000 miles I would try to avoid long trips or periods where you're operating at a constant engine speed," says Chacon.

OK, so staying at any one engine speed is bad, but this isn't to say you can go take your new engine to six grand the first time out. On the contrary, restraint must be used to keep engine speeds and loads reasonably in check. "Don't go out there and just hammer through the gears all the time; you need to be a little more conservative about how you drive the vehicle. A varied range of rpm usage, combined with keeping it easy on the motor, allows the face on the ring to do a better job of seating to the cylinder wall," says Chacon.

Full article is at http://www.gmhightechperformance.com/tech/0701gm_ls1_engine_build/index.html

//2000CAYukon

I just talked to the dealer, and they told me to drive it like I stole it. Just bring it in for a complimentary oil change after the first 1000 miles.

Apparently with the non-performance GM crate engines, all that is really needed is the first 10 mile break-in done by the dealer, after that you can drive as normal.

I'm still probably gonna take it easy the first few thousand miles though.lol And yeah, I've been trying not to stay at the same speed for a long time. Cruise control is off limits for a while.lol

I just talked to the dealer, and they told me to drive it like I stole it. Just bring it in for a complimentary oil change after the first 1000 miles.

Apparently with the non-performance GM crate engines, all that is really needed is the first 10 mile break-in done by the dealer, after that you can drive as normal.

I'm still probably gonna take it easy the first few thousand miles though.lol And yeah, I've been trying not to stay at the same speed for a long time. Cruise control is off limits for a while.lol

I only buy new vehicles....my first was in 1967...my lastest and 4th vehicle is a 2000 silverado..

I drive the first 500miles easy and vary speeds,,,usually take back road and let the engine settle in...then the next 500miles on the highway I keep it at 55-60mph then every 10 miles floor it to 70mph then let it coast down to 55-60mph...

at 1000mi I change oil/filter ,,,then after 2000-2500miles replace oil/filter...

usually at 10,ooomi the engine is now fully broken in and the MPG is set..prior to break in the MPG will be low....and oil is used...

I have been fortunate as I have never had any engine jobs /or replacements...

the vehicle that preceeded my 2000 silverado had 380,ooomi...and used 1/3qt of oil at the 3000mi oil change interval...10-30wt castrol....never failed an emissions test even at the 370,ooomi mark ...

with proper maintanence and reasonable operation this should last many years....

most engines today fail because of poorly maintaned coolant systems...once these engines get corroded and heat up its junk..