Gordonm

I was at the Michigan facility that builds the LS7 motors and they all had Mobil 1 in them from the get go.

Jebbysan

corvettedave383

Ive read a detailed build of my engine type at GM, engine isnt started, just primed with oil to make sure its getting oil pressure, thats it, maybe iam wrong

Gordonm

Looking into this a little deeper this is an ongoing debate on most forums. Most of the top engine builders state now with the machining tolerances now that can be held with modern equipment there is no need to "break in" the motors. Rings included. From all that I have seen and read all the GM LS engines come with synthetic oil from the first fire of the spark plugs.

There is a lot of myths and speculation out there and I am no expert or engineer as there are a lot smarter engineers at GM that design this but if the block is machined correctly the rings will seat with either type of oil.

Open for discussion

ignatz

The crate motor was dry. My Z06/LS7 of course came with oil. The crate motor comes with a very detailed set of break-in instructions and it includes Mobil 1.

jb78L-82

Yes Correct my LS7 Z06 came with Mobil 1 5-30 synthetic from the factory as well, BUT all GM engines and cars come with a detailed breakin procedure regardless of the factory oil fill. I think that the tolerances are MUCH tighter on new generation engines which as surmised allows for synthetic oil to be used during breakin versus conventional oil for breakin on my Gen 1 355 L-82 after its rebuild. The notion that keeps coming up, though, that newer GM engines, crate motors, roller cammed Gen 1 SBC, or ANY motor when new does not need a breakin, frankly, is a little ridiculous. The fact is that any new motor with new parts will experience metal shavings and filings during the first 1,000 miles or so. Those metal shavings and parts can and will contaminate the new engine internals if not done progressively with subsequent oil/filter changes....There is no getting around this new engine event.
Those who start new engines and let er rip are most likely not going to see the fruits, or lack there off, until later in the engine's life. I mentioned this earlier in another thread, that I am often shocked at the very few thousand miles some of these rebuilt SBC's go before another rebuild is necessary and I am beginning to understand the cause of this event?????!!!

bluegtp

Same here....plus I broke a exhaust manifold bolt off in the head (late at night test fitting headers and forgot to put antisieze on ss bolts. I pulled head to have it removed before i cranked it. The pistons looked brand new, plus there were paint or sharpie marks on top of pistons. I doubt those would've survived breaking in.

71 Vert LS1

I've had a few LS engines built over the years. First start on a engine dyno with dino oil typically 10-30 race? oil. Then after a short run up to temp both the oil filter and oil are dropped and filled with 10-30 Mobil 1. That is what the engine builder likes so who am I to second guess. All have run well.

kossuth

Those motors are built to a far tighter tolerance than the old motors. That and the camshafts in the newer motors are roller from the factory. No need to run a break in oil because there really isn't much to break in.

jb78L-82

Here is non auto engine anecdote.

Brand new lawn tractor with 15 hp Kohler Command Engine in 1998. Kohler says breakin the engine using 10W-30 conventional oil for 25 hours and then change oil/filter. I always warmed the engine to operating temp during the breakin 25 hours before using. I do just that and then switch to 5W-30 Mobil 1, later Mobil 1 15W-50, and for about the last 10 years Mobil 1 0W-40 European Formula, none of which is specified by Kohler as an approved weight OR to use a synthetic, over the intervening 22 years. This engine today has somewhere between 2,500-3,000 hours on it cutting grass and does not burn 1 drop of oil during the cutting season. I change the oil and filter once per year, 2 qts Mobil 1 synthetic, and good to go.

2 points:
This engine required a conventional oil breakin and the synthetic oil has no doubt allowed this engine to operate with zero oil usage after so many hours. The local lawn repair guys are astounded that the engine is still operating and burns zero oil. Hmmmmmmmmm

resdoggie

15 hp Kohler Command Engine - you can't kill it! LOL! Had mine for 13 years and only changed the oil twice! Used the JD LT150 in the winter too with a 42" snowblower.

I think engine design technology has progressed to the point where break-in is not required on some engines but is on others. Rings are designed to seat with dino or synthetic oils from first start-up, afaik.