corvettedave383

Ive searched these forums and others, cant really get an exact answer relating to my question

Ive got a new LSX b15 crate engine from GM, trying find out what run in oil to use - mineral or fully synthetic?
the gm create instructions say to use a fully synthetic oil at break in?

general talk on the web seem to suggest mineral to start with or is that relating to older engines or ??

thoughts?

cv67

Id listen to GM long before someone on the web. Some crazy suggestions floating around out there. lol

v2racing

Just do what GM recommends.

Mike

jb78L-82

GM's Direction as well and no one elses

roboto65

CA_WxMan

A common reply is to "use whatever your engine builder recommends". So in the case of a GM crate engine, follow GM's instructions.

bfit

corvettedave383

Ok guys thanks for your inputs, you can see my point, theres companys out that make run in oil for are engines, so all very confusing

flyeri

Do what the builder says. No one else's opinion matters. To quote the instructions:

1. The LSX engines require a special oil meeting GM Standard GM4718M (this will be specified on the oil label). Mobil 1 is one such recommended oil. Other oils meeting this standard may be identified as synthetic. However, not all synthetic oils will meet this GM standard. Look for and use only oil that meets GM Standard GM4718M.
   

ignatz

The other thing that is going to scare you Dave, is no pre-oiling in the conventional sense with a drill motor. And there's no place to use one anyway. Just crank until the pressure comes up, but with fuel and ignition off. Lines 2 and 3 in Start-up and Break-in in my literature. It takes awhile the first time given the long pickup, but once it is there it's good from then on.

mirage2991

bluegtp

I just got my ls3 running a few months ago. Followed gm's start up insturctions (5w30, prime engine oil, etc) and done. I think they recommend to drive for 30 miles, change and then 500 miles. I'm sure similar for you motor. Good luck.

3X2

We use Mobil 1 15w-50 in our race/track day engines and Mobil 1 5w-30 in the street car engines. As far as priming, dis able the ignition and, if equipped, the electric fuel pump. Remove all the plugs and crank the engine. I do about a 15 second crank then a 1 minute cool down. Repeat until you see pressure on the gauge. Kent Moore does sell a tool that mounts where the oil filter goes and then you would use a glorified bug sprayer filled with oil to prime the engine.

jb78L-82

FWIW-As discussed above ^^^ by a few, no breakin oil required BUT YES, there is a breakin procedure from GM ( and for most engines regardless) because a new engine is a new engine with metal on metal wear on parts and metal filings, regardless.

Just a an aside, since my 10C6Z06 LS7 427 sit weeks and sometimes, months at a time, I ALWAYs prime the motor before starting in the garage. How? Easy, on GM cars, hold the gas pedal to the floor and press the start button (and keep your foot to the floor on the gas) which is GM's flood clearing procedure. The engine will crank only and will not fire. I do this for 2-3 15 seccond intervals, waiting 30 seconds between priming runs. Then just hit the start button as normal and the 427 fires immediately to life, with zero engine clattering by the way.

Same for the 78 L-82 355 roller cam AFR engine. Always prime with starter on first cold start. Crank for 15 seconds with no choke, wait 30 seconds, between cranks, wait for oil pressure to hit 60 lbs. Set choke and fire her up........

juanvaldez

I would use a 5w30 conventional diesel oil (high in zinc). I found some Motorcraft 5w30 diesel oil at Walmart.

jb78L-82

There is zero need to use diesel oil in gas engines for ZDDP since there are many high Zinc gas oils as well. I am always perplexed by folks who use diesel oils in gas engines since diesel and gas engines are very different and have different lubrication requirements......

resdoggie

Pssst, please keep that myth to yourself.

Gordonm

Agreed and with a roller cam in the LS motors there is no need for high zinc oils. GM uses synthetics for a reason in these motors, because it works.

Jebbysan

Even though your engine may have came with synthetic in the crankcase new.......the engine is run beforehand to seat rings with mineral oil.

Jebby

ignatz

Are you referring to GM crate engines? I have no awareness of any mention in my instructions. There certainly was no oil in the crankcase.