Break in oil??

CASHKJ

Original poster
Member
Feb 4, 2013
28
Just finished rebuild new crank,bearings and pistons on 2006 trailblazer 4.2 what would be a good break in oil and what filter?

Thanks!
 

Matt

Member
Dec 2, 2011
4,025
Why don't you just run synthetic through it from the beginning? If it were me, I'd be running Mobil 1 or AMSOIL straight from the start.

Wix, Mobil 1 and Bosch are all good filters, with Wix and Mobil 1 some of the best...stay away from Fram.
 

jimmyjam

Member
Nov 18, 2011
1,634
Matt said:
Why don't you just run synthetic through it from the beginning?
because you need the rings to seat.

i used joe gibbs break in oil
 

Matt

Member
Dec 2, 2011
4,025
jimmyjam said:
because you need the rings to seat.

i used joe gibbs break in oil

Fair enough...although:

Myth #6

Engines have to be "broken in" before using synthetic oil. I need to break in my engine with non-detergent oil. If I use regular oil or synthetic oil in a new engine, my engine will take longer to break in.
Fact

It was common years ago for engine manufacturers to recommend non-detergent oils for engine break-in. This was when the pistons used cast-iron "square-faced" rings and the rings needed to wear some to "seat" into the engine. With today's technology of oils and engine manufacturing, engine manufacturers no longer recommend the use of non-detergent oils for the break-in period. In fact, engines today are factory-filled with high quality API SL performance motor oil, which contains high levels of detergents and dispersant additives.
from: Performance Plus Oil / Myths Of Motor Oil

MYTH: You should break in your engine with conventional oil, then switch to a synthetic like Mobil 1™ oil.

REALITY: You can start using Mobil 1 synthetic oil in new vehicles at any time, even in brand new vehicles. In fact, Mobil 1 synthetic is original equipment (it is installed at the factory) in:

Acura RDX
Aston Martin DB9, DB9 Volante, DBS, DBS Volante, Virage, Virage Volante, Rapide
Bentley Azure, Brooklands, Continental Flying Spur, Continental GT, Continental GTC, Mulsanne
Chevrolet Corvette Z06, ZR1 and Grand Sport Coupe
Chevrolet CR8 and COPO Camaro
Citröen DS3
Holden HSV
Lexus LFA
McLaren MP4-12C
Mercedes-Benz AMG Vehicles
Nissan GT-R
All Porsche Vehicles
Peugeot RCZ
Vauxhall VXR8
Viper Motorcycles

One of the myths surrounding synthetic oils is that new engines require a break-in period with conventional oil. The fact is, current engine manufacturing technology does not require this break-in period. As indicated by the decisions of the engineers who design the high-performance cars listed above, Mobil 1 synthetic motor oil can be used starting the day you drive the car off the showroom floor.
from: Synthetic Oil | Frequently Asked Questions

NOW YOU KNOW: Is synthetic oil too slippery for proper break-in?
Conventional wisdom says that a new engine should be broken in on conventional mineral oil, regardless of your intentions to use a synthetic for the long haul. The conventionally wise say that synthetic oil is too slippery and won’t let the microscopic high points properly lap themselves in, delaying the break-in process. I say rubbish. Many modern cars, notably such high-performance marques as Porsche, Ferrari and Corvette, are factory-​filled with synthetics. You can bet that somebody has determined that the break-in process will proceed normally with synthetic in the sump of these ultra-high-performance engines. And that goes for your Toyota or Jeep as well.

Nonetheless, I do prefer to use a mineral oil for break-in. It’s $3 a quart versus $7, so I don’t mind changing it after 20 miles and again at 1000.

I would not, however, change the factory-fill synthetic back to mineral for break-in. Those vehicles typically have carefully assembled engines with instructions to do the first oil change at the regular interval, which could be up to 10,000 miles. In those cases, I simply change the oil early, before 1000 miles, just to be safe.

Synthetic oil is a superior product, particularly if your engine operates at the extreme ends of the temperature scale: high-temperature climates, towing or racing. But like any oil, synthetic will become contaminated with atmospheric dirt, wear particles, carbon, partially burned fuel, water and acid. Eventually, even if the oil itself is performing properly, all this extra junk will manifest itself as engine wear.

Also, the first oil change invariably reveals small particles of gasket sealer, chunks of unidentified plastic, the occasional metal flakes that weren’t cleaned off before assembly and even the odd washer or nut. It’s pretty scary. Better this junk come out sooner rather than later.
from: New Car Care – How to Take Care of a New Car - Popular Mechanics

Not saying you're wrong by any means...it looks as though there is a divided opinion on what to use. So, at the end of the day, I guess it's up to the OP on what they want to use. :smile:
 

v7guy

Member
Dec 4, 2011
298
Using regular oil makes sense if from only the perspective of you are tossing it out pretty quick. I've always used regular for break in and then switched to the synthetics afterwards. I've always gone this route because it is "conventional" wisdom.
As stated above, it's essentially a judgement/preference call.

Matt posted some good stuff there
 

jimmyjam

Member
Nov 18, 2011
1,634
i think there are two different scenarios here. one is a diy rebuild, the other is buying a new car off of the lot, draining the oil, and putting in break in oil. I don't know much about new cars, never bought one, probably never will. it seems to me like that is what these quotes are addressing. if you buy a new car, do what the manf tells you to do; they are warrantying it. i don't know what they did to that car/engine before it hit the lot, all i know is it has oil in it and they'll probably tell you to bring it back in 500mi to change the oil? again, i have no idea...

all i can comment on is a rebuild. you put the valve covers on, fill it with oil, and cross your fingers. I don't know much about the history of piston rings, and i'm not a mechanical engineer. so the ring seating a topic up for debate... i'm unqualified to comment on it. however there is one thing i'm sure of, you are going to change the oil after an hour or two of engine time regardless due to a)flushing out the all the assembly lube b) the metal content of the oil from the virgin mating surfaces. so you have two choices, use a break-in oil, or if you feel like you don't think there is any benefit, use the cheapest oil you can find, since it is getting replaced very soon anyway. that being said, i bought a $9k longblock, when i opened up the crate, there is a case of break in oil in there, and a letter that says use it or there is no warranty

so in short what i'm saying is i wouldn't use a high priced regular synth from day 1 since that oil is coming out fairly soon regardless
 

Matt

Member
Dec 2, 2011
4,025
jimmyjam said:
so in short what i'm saying is i wouldn't use a high priced regular synth from day 1 since that oil is coming out fairly soon regardless

Absolutely agree, once I thought about it. Why spend the $60 +/- on synth when you are going to get rid of it after such a short amount of time.
 

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